Carolina Power and Light Company, H.B. Robinson Steam Electric Plant, Unit No. 2; Exemption, 44942-44946 [E5-4147]

Download as PDF 44942 Federal Register / Vol. 70, No. 149 / Thursday, August 4, 2005 / Notices In accordance with 10 CFR 2.390 of NRC’s ‘‘Rules of Practice,’’ final NRC records and documents regarding this proposed action are publically available in the records component of NRC’s Agencywide Documents Access and Management System (ADAMS). The request for exemption dated June 13, 2005, and July 20, 2005, was docketed under 10 CFR Part 72, Docket No. 72– 60. These documents may be inspected at NRC’s Public Electronic Reading Room at http://www.nrc.gov/readingrm/adams.html. These documents may also be viewed electronically on the public computers located at the NRC’s Public Document Room (PDR), O1F21, One White Flint North, 11555 Rockville Pike, Rockville, MD 20852. The PDR reproduction contractor will copy documents for a fee. Persons who do not have access to ADAMS or who encounter problems in accessing the documents located in ADAMS, should contact the NRC PDR Reference staff by telephone at 1–800–397–4209 or (301) 415–4737, or by e-mail to pdr@nrc.gov. Dated at Rockville, Maryland, this 29th day of July, 2005. For the Nuclear Regulatory Commission. L. Raynard Wharton, Project Manager, Spent Fuel Project Office, Office of Nuclear Material Safety and Safeguards. [FR Doc. E5–4145 Filed 8–3–05; 8:45 am] BILLING CODE 7590–01–P NUCLEAR REGULATORY COMMISSION [Docket No. 50–261] Carolina Power and Light Company, H.B. Robinson Steam Electric Plant, Unit No. 2; Exemption 1.0 Background Carolina Power & Light Company (CP&L or the licensee) is the holder of Renewed Facility Operating License No. DPR–23, which authorizes operation of the H. B. Robinson Steam Electric Plant, Unit No. 2 (HBRSEP2). The license provides, among other things, that the facility is subject to all rules, regulations, and orders of the Nuclear Regulatory Commission (NRC, the Commission) now or hereafter in effect. The facility consists of a pressurizedwater reactor located in Darlington County, South Carolina. 2.0 Request/Action By letter dated February 22, 2005, as supplemented by letters dated May 10, July 6, and July 14, 2005, the licensee submitted a request for an exemption from the requirements of Title 10 of the VerDate jul<14>2003 16:23 Aug 03, 2005 Jkt 205001 Code of Federal Regulations (10 CFR) Section 50.68(b)(1) during the spent fuel pool (SFP) activities related to the underwater handling, loading, and unloading of the dry shielded canister (DSC) NUHOMS –24PTH, as described in proposed Amendment No. 8 to Certificate of Compliance No. 1004 listed in 10 CFR 72.214 at HBRSEP2. Section 50.68(b)(1) of 10 CFR sets forth the following requirement that must be met, in lieu of a monitoring system capable of detecting criticality events. Plant procedures shall prohibit the handling and storage at any one time of more fuel assemblies than have been determined to be safely subcritical under the most adverse moderation conditions feasible by unborated water. The licensee is unable to satisfy the above requirement for handling of the Transnuclear (TN) NUHOMS–24PTH DSC authorized by 10 CFR Part 72 at HBRSEP2. Section 50.12(a) allows licensees to apply for an exemption from the requirements of 10 CFR Part 50 if the application of the regulation is not necessary to achieve the underlying purpose of the rule and special conditions are met. The licensee stated in the application that compliance with 10 CFR 50.68(b)(1) is not necessary for handling the TN NUHOMS–24PTH DSC system to achieve the underlying purpose of the rule. 3.0 Discussion Pursuant to 10 CFR 50.12, the Commission may, upon application by any interested person or upon its own initiative, grant exemptions from the requirements of 10 CFR Part 50 when (1) the exemptions are authorized by law, will not present an undue risk to public health or safety, and are consistent with the common defense and security; and (2) when special circumstances are present. Therefore, in determining the acceptability of the licensee’s exemption request, the staff has performed the following regulatory, technical, and legal evaluations to satisfy the requirements of 10 CFR 50.12 for granting the exemption. 3.1 Regulatory Evaluation The HBRSEP2 Technical Specifications (TS) currently permit the licensee to store spent fuel assemblies in high-density storage racks in its SFP. In accordance with the provisions of 10 CFR 50.68(b)(4), the licensee takes credit for soluble boron for criticality control and ensures that the effective multiplication factor (keff) of the SFP does not exceed 0.95, if flooded with borated water. Section 50.68(b)(4) of 10 CFR also requires that if credit is taken PO 00000 Frm 00060 Fmt 4703 Sfmt 4703 for soluble boron, the keff must remain below 1.0 (subcritical) if flooded with unborated water. However, the licensee is unable to satisfy the requirement to maintain the keff below 1.0 (subcritical) with unborated water, which is also the requirement of 10 CFR 50.68(b)(1), during cask handling operations in the SFP. Therefore, the licensee’s request for exemption from 10 CFR 50.68(b)(1) proposes to permit the licensee to perform spent fuel loading, unloading, and handling operations related to dry cask storage without being subcritical under the most adverse moderation conditions feasible by unborated water. Title 10 of the Code of Federal Regulations, Part 50, Appendix A, ‘‘General Design Criteria (GDC) for Nuclear Power Plants,’’ provides a list of the minimum design requirements for nuclear power plants. According to GDC 62, ‘‘Prevention of criticality in fuel storage and handling,’’ the licensee must limit the potential for criticality in the fuel handling and storage system by physical systems or processes. HBRSEP2 was licensed prior to the issuance of the GDC listed in 10 CFR 50, Appendix A; therefore, GDC 62 is not directly applicable. However, HBRSEP2 has committed to a plant-specific version of the 1967 draft GDC as discussed in its Updated Final Safety Analysis Report (FSAR), Section 3.1.2. The comparable GDC is Criterion 66, ‘‘Prevention of Fuel Storage Criticality,’’ that states: ‘‘Criticality in the new and spent fuel storage pits shall be prevented by physical systems or processes. Such means as geometrically safe configurations shall be emphasized over procedural controls.’’ Section 50.68 of 10 CFR Part 50, ‘‘Criticality accident requirements,’’ provides the NRC requirements for maintaining subcritical conditions in SFPs. Section 50.68 provides criticality control requirements that, if satisfied, ensure that an inadvertent criticality in the SFP is an extremely unlikely event. These requirements ensure that the licensee has appropriately conservative criticality margins during handling and storage of spent fuel. Section 50.68(b)(1) states, ‘‘Plant procedures shall prohibit the handling and storage at any one time of more fuel assemblies than have been determined to be safely subcritical under the most adverse moderation conditions feasible by unborated water.’’ Specifically, 10 CFR 50.68(b)(1) ensures that the licensee will maintain the pool in a subcritical condition during handling and storage operations without crediting the soluble boron in the SFP water. The licensee is authorized under general license to construct and operate E:\FR\FM\04AUN1.SGM 04AUN1 Federal Register / Vol. 70, No. 149 / Thursday, August 4, 2005 / Notices an Independent Spent Fuel Storage Installation (ISFSI) at HBRSEP2. The ISFSI permits the licensee to store spent fuel assemblies in large concrete dry storage casks. As part of its ISFSI loading campaigns, the licensee transfers spent fuel assemblies to a DSC in the cask pit area of the SFP. The licensee performed criticality analyses of the DSC fully loaded with fuel having the highest permissible reactivity and determined that a soluble boron credit was necessary to ensure that the DSC would remain subcritical in the SFP. Since the licensee is unable to satisfy the requirement of 10 CFR 50.68(b)(1) to ensure subcritical conditions during handling and storage of spent fuel assemblies in the pool with unborated water, the licensee identified the need for an exemption from the 10 CFR 50.68(b)(1) requirement to support DSC loading, unloading, and handling operations without being subcritical under the most adverse moderation conditions feasible by unborated water. The NRC staff evaluated the possibility of an inadvertent criticality of the spent nuclear fuel at HBRSEP2 during DSC loading, unloading, and handling. The NRC staff has established a set of acceptance criteria that, if met, satisfy the underlying intent of 10 CFR 50.68(b)(1). In lieu of complying with 10 CFR 50.68(b)(1), the staff determined that an inadvertent criticality accident is unlikely to occur if the licensee meets the following five criteria: 1. The cask criticality analyses are based on the following conservative assumptions: a. All fuel assemblies in the cask are unirradiated and at the highest permissible enrichment, b. Only 75 percent of the Boron-10 in the fixed poison panel inserts is credited, c. No credit is taken for fuel-related burnable absorbers, and d. The cask is assumed to be flooded with moderator at the temperature and density corresponding to optimum moderation. 2. The licensee’s ISFSI TS require the soluble boron concentration to be equal to or greater than the level assumed in the criticality analysis, and surveillance requirements necessitate the periodic verification of the concentration both prior to and during loading and unloading operations. 3. Radiation monitors, as required by GDC 63, ‘‘Monitoring Fuel and Waste Storage,’’ are provided in fuel storage and handling areas to detect excessive radiation levels and to initiate appropriate safety actions. 4. The quantity of other forms of special nuclear material, such as VerDate jul<14>2003 16:23 Aug 03, 2005 Jkt 205001 sources, detectors, etc., to be stored in the cask will not increase the effective multiplication factor above the limit calculated in the criticality analysis. 5. Sufficient time exists for plant personnel to identify and terminate a boron dilution event prior to achieving a critical boron concentration in the DSC. To demonstrate that it can safely identify and terminate a boron dilution event, the licensee must provide the following: a. A plant-specific criticality analysis to identify the critical boron concentration in the cask based on the highest reactivity loading pattern. b. A plant-specific boron dilution analysis to identify all potential dilution pathways, their flowrates, and the time necessary to reach a critical boron concentration. c. A description of all alarms and indications available to promptly alert operators of a boron dilution event. d. A description of plant controls that will be implemented to minimize the potential for a boron dilution event. e. A summary of operator training and procedures that will be used to ensure that operators can quickly identify and terminate a boron dilution event. On March 23, 2005, the NRC issued Regulatory Issue Summary (RIS) 2005– 05, ‘‘Regulatory Issues Regarding Criticality Analyses for Spent Fuel Pools and Independent Spent Fuel Storage Installations.’’ In RIS 2005–05, the NRC identified an acceptable methodology for demonstrating compliance with the 10 CFR 50.68(b)(1) requirements during cask loading, unloading, and handling operations in pressurized-water reactor SFPs. The NRC staff has determined that implementation of this methodology by licensees will eliminate the need to grant future exemptions for cask storage and handling evolutions. However, since the licensee submitted its exemption request prior to issuance of the RIS and identification of an NRCacceptable methodology for compliance with the regulations, the NRC staff has determined that it is still appropriate to consider the exemption request. 3.2 Technical Evaluation In determining the acceptability of the licensee’s exemption request, the staff reviewed three aspects of the licensee’s analyses: (1) criticality analyses submitted to support the ISFSI license application and its exemption request, (2) boron dilution analysis, and (3) legal basis for approving the exemption. For each of the aspects, the staff evaluated whether the licensee’s analyses and methodologies provide reasonable assurance that adequate safety margins are developed and can be maintained in PO 00000 Frm 00061 Fmt 4703 Sfmt 4703 44943 the HBRSEP2 SFP during loading of spent fuel into canisters for dry cask storage. 3.2.1 Criticality Analyses For evaluation of the acceptability of the licensee’s exemption request, the NRC staff reviewed the criticality analyses provided by the licensee in support of its ISFSI license application. First, the NRC staff reviewed the methodology and assumptions used by the licensee in its criticality analysis to determine if Criterion 1 was satisfied. The licensee stated that it took no credit in the criticality analyses for burnup or fuel-related burnable neutron absorbers. The licensee also stated that all assemblies were analyzed at the highest permissible enrichment. Additionally, the licensee stated that all criticality analyses for a flooded DSC were performed at temperatures and densities of water corresponding to optimum moderation conditions. Finally, the licensee stated that it credited 90 percent of the Boron-10 content for the fixed neutron absorber in the DSC. NUREG–1536, ‘‘Standard Review Plan for Dry Cask Storage System,’’ states that ‘‘[f]or a greater credit allowance [i.e., greater than 75 percent for fixed neutron absorbers] special, comprehensive fabrication tests capable of verifying the presence and uniformity of the neutron absorber are needed.’’ As part of an amendment to the Part 72 license for the Transnuclear NUHOMS–24PTH design, the NRC staff reviewed and accepted the results of additional data supplied by the manufacturer that demonstrated that a 90-percent credit for the fixed neutron absorbers was acceptable. These tests and corresponding results are detailed in Appendix P of the Standardized NUHOMS FSAR. Therefore, for the purposes of this exemption, the staff finds a 90-percent credit acceptable on the basis that it has previously been reviewed and approved by the NRC. Subsequently, based on its review of the criticality analyses and the information submitted in its exemption request, the NRC staff finds that the licensee has satisfied Criterion 1. Second, the NRC staff reviewed the proposed HBRSEP2 ISFSI TS. The licensee’s criticality analyses credit soluble boron for reactivity control during DSC loading, unloading, and handling operations. Since the boron concentration is a key safety component necessary for ensuring subcritical conditions in the pool, the licensee must have a conservative ISFSI TS capable of ensuring that sufficient soluble boron is present to perform its safety function. The ISFSI TS applicable E:\FR\FM\04AUN1.SGM 04AUN1 44944 Federal Register / Vol. 70, No. 149 / Thursday, August 4, 2005 / Notices to the NUHOMS–24PTH DSC, and attached to the Certificate of Compliance No. 1004, contain the requirements for the minimum soluble boron concentration as a function of fuel assembly class, DSC basket type, and corresponding assembly average initial enrichment values. In all cases, the boron concentration required by the ISFSI TS ensures that the keff will be below 0.95 for the analyzed loading configuration. Additionally, the licensee’s ISFSI TS contain surveillance requirements that assure it will verify the boron concentration is above the required level both prior to and during DSC loading, unloading, and handling operations. Based on its review of the HBRSEP2 ISFSI TS, the NRC staff finds that the licensee has satisfied Criterion 2. Third, the NRC staff reviewed the HBRSEP2 Updated FSAR and the information provided by the licensee in its exemption request to ensure that it complies with GDC 63. GDC 63 requires that licensees have radiation monitors in fuel storage and associated handling areas to detect conditions that may result in a loss of residual heat removal capability and excessive radiation levels and initiate appropriate safety actions. As previously described, HBRSEP2 was licensed prior to the issuance of the GDC listed in 10 CFR 50, Appendix A; therefore, GDC 63 is not directly applicable. However, HBRSEP2 has committed to a plant-specific version of the 1967 draft GDC as discussed in its Updated FSAR, Section 3.1.2. The comparable GDC is Criterion 18, ‘‘Monitoring Fuel and Waste Storage,’’ that states the following: ‘‘Monitoring and alarm instrumentation shall be provided for fuel and waste storage and associated handling areas for conditions that might result in loss of capability to remove decay heat and detect excessive radiation levels.’’ The NRC staff reviewed the HBRSEP2 Updated FSAR, plant-specific GDC, and exemption request to determine whether the licensee had provided sufficient information to demonstrate compliance with the intent of GDC 63. In its exemption request, the licensee stated that an area radiation monitor is located in the area of the SFP. Additionally, station procedures specify appropriate safety actions upon a high radiation alarm, including evacuation of local personnel, determination of cause, and determination of potential low water level in the SFP. In addition, personnel working in the area of the SFP wear individual, gamma-sensitive, electronic alarming dosimeters that provide an audible alarm should the dose or dose VerDate jul<14>2003 16:23 Aug 03, 2005 Jkt 205001 rate exceed pre-established setpoints. Based on its review of the exemption request, the HBRSEP2 Updated FSAR, and the licensee’s plant-specific GDC, the NRC staff finds that the licensee has satisfied Criterion 3. Finally, as part of the criticality analysis review, the NRC staff evaluated the storage of non-fuel-related material in a DSC. The NRC staff evaluated the potential to increase the reactivity of a DSC by loading it with materials other than spent nuclear fuel and fuel debris. The approved contents for storage in the NUHOMS–24PTH cask design are listed in the HBRSEP2 ISFSI TS Limiting Condition for Operation (LCO) 1.2.1 ‘‘Fuel Specifications.’’ This ISFSI TS LCO restricts the contents of the DSC to only fuels and non-fissile materials irradiated at HBRSEP2. As such, HBRSEP2 is prohibited from loading other forms of special nuclear material, such as sources, detectors, etc., in the DSC. Therefore, the NRC staff determined that the loading limitations described in the HBRSEP2 ISFSI TS will ensure that any authorized components loaded in the DSCs will not result in a reactivity increase. Based on its review of the loading restrictions, the NRC staff finds that the licensee has satisfied Criterion 4.3.2.2. Boron Dilution Analysis. Since the licensee’s ISFSI application relies on soluble boron to maintain subcritical conditions within the DSCs during loading, unloading, and handling operations, the NRC staff reviewed the licensee’s boron dilution analysis to determine whether appropriate controls, alarms, and procedures were available to identify and terminate a boron dilution accident prior to reaching a critical boron concentration. By letter dated October 25, 1996, the NRC staff issued a safety evaluation on licensing topical report WCAP–14416, ‘‘Westinghouse Spent Fuel Rack Criticality Analysis Methodology.’’ This safety evaluation specified that the following issues be evaluated for applications involving soluble boron credit: the events that could cause boron dilution, the time available to detect and mitigate each dilution event, the potential for incomplete boron mixing, and the adequacy of the boron concentration surveillance interval. The criticality analyses performed for the NUHOMS–24PTH DSC are described in Section 6 of Appendix P of the FSAR for the Standardized NUHOMS Horizontal Modular Storage System for Irradiated Nuclear Fuel. For this boron dilution evaluation, the licensee employed the same criticality analysis methods, models, and assumptions. These HBRSEP2 criticality PO 00000 Frm 00062 Fmt 4703 Sfmt 4703 calculations are based on the KENO V.a code. The calculations determined the minimum soluble boron concentration required to maintain subcriticality (keff < 1.0) following a boron dilution event in a NUHOMS–24PTH DSC loaded with fuel assemblies that bound the HBRSEP2 fuel designs (Westinghouse 15 x 15 fuel). Both intact and damaged fuel over the range of soluble boron concentrations permitted for various enrichments and basket types were evaluated. The results of these calculations for the bounding case indicate that subcriticality is maintained with 73 percent or more of the minimum boron concentration levels required in the ISFSI TS for all basket types as a function of initial enrichment. Calculations were performed by the licensee to determine the time required to dilute the SFP such that the boron concentration is reduced from the NUHOMS TS (required boron concentration for maintaining keff < 0.95) to a just subcritical boron concentration (keff < 1.0) for fuel loaded into a NUHOMS–24PTH DSC. The HBRSEP2 SFP is a large structure filled with borated water that completely covers the spent fuel assemblies with more than 21 feet of water above the top of the fuel racks and the fuel cask. The cask lay down area is not separated by any structure from the remainder of the SFP. Thermal gradients generated by stored fuel and operation of the SFP cooling system will cause significant mixing within the pool. The licensee assumed that all unborated water introduced from any uncontrolled dilution source instantaneously mixes with the water in the SFP (i.e., no unborated water is lost prior to its mixing with borated water). The configuration of the pool and the mixing of the coolant provide reasonable assurance that this assumption is valid for low to moderate dilution flow rates. The volume of water in the SFP is 240,000 gallons. To reduce the boron concentration by a factor of 0.73 from the TS for keff ≤ 0.95 and approach a keff of 1.0 requires the addition of 75,530 gallons of unborated water. Three examples of potential dilution sources were identified by the licensee: a 2-gpm flowrate from small failures or misaligned valves that could occur in the normal soluble boron control system or related systems, the failure of the 2inch demineralized water header, and the maximum credible dilution event involving the rupture of a fire protection system header. To demonstrate that sufficient time exists for plant personnel to identify and terminate a boron dilution event, the licensee provided a description of E:\FR\FM\04AUN1.SGM 04AUN1 Federal Register / Vol. 70, No. 149 / Thursday, August 4, 2005 / Notices all alarms available to alert operators, and plant procedures, administrative controls, and training that will be implemented in response to an alarm. There is no automatic level control system for the SFP; therefore, any large, uncontrolled water addition would cause the SFP to overflow. However, a high level alarm in the control room would alert personnel of a potential boron dilution event when the water level reaches the high level setpoint. The highest uncontrolled dilution flow rate was determined to be the fire protection header on the SFP floor for fire hose station 104. As stated in the letter dated July 6, 2005, this fire protection header will be isolated during DSC loading and unloading to preclude this as a source of uncontrolled dilution to the SFP. The licensee has revised DSC loading and unloading procedures to include a requirement to close the fire protection system valve (FP–71) prior to placing fuel in the DSC during loading and prior to placing the loaded DSC back in the SFP during unloading. This change has resulted in the most limiting uncontrolled dilution source being identified as the assumed break of a 2inch demineralized water header, which could cause a dilution flow of approximately 103 gpm. No other single source has been identified that would exceed this dilution rate. Therefore, the time to reach a critical boron concentration, as provided by licensee, is estimated to be 755 minutes. In the case of the 103-gpm demineralized water pipe rupture, there would be no alarm from the demineralized water system. However, there would be available approximately 10 hours to isolate the leak once the SFP high level alarm was received. This analysis provides reasonable assurance that dilution flows leading to pool overflow would be detected and isolated well before the critical boron concentration could be reached from credible dilution sources. The licensee stated that plant procedures do allow for continued operation with the SFP high level alarm illuminated. The licensee stated that operating procedures had been revised to specify that, if the SPF high level alarm is illuminated and there is fuel in the DSC in the SFP, then continuous coverage to monitor the SFP water level will be required. A local level indicator is available in the SFP. The personnel providing continuous coverage when the SFP Hi Level Alarm is illuminated or inoperable can use this indication to detect possible dilution of the SFP. The available time before criticality by dilution is sufficient to allow VerDate jul<14>2003 16:23 Aug 03, 2005 Jkt 205001 identification and termination of any credible source of dilution. When fuel is loaded in the DSC in the SFP, boron analyses of the SFP water are required at least once every 48 hours per the TS. Small dilution flows may not be readily identified by level changes in the SFP due to operational leakage through the pool liner and the SFP cooling system. The licensee determined that a dilution flow of 2 gpm would require approximately 26 days to dilute the boron concentration of the SFP near to that calculated as the critical boron concentration. Therefore, the reduction in boron concentration due to a dilution flowrate of 2 gpm would be detected by the required boron concentration surveillance well before a significant dilution occurs. To ensure that operators are capable of identifying and terminating a boron dilution event during DSC loading, unloading, and handling operations, operator training will be conducted. This training will highlight the boron concentration requirements for loading the DSC, the potential for criticality should boron concentration levels decrease, and the need for timely mitigating activities if a boron dilution event occurs. Operators and other personnel involved in the dry fuel storage implementation will receive this new training prior to loading of the first DSC. Additionally, before each DSC loading evolution, the crew involved in performance of the work will receive a pre-job briefing, where the need for boron concentration control will be discussed. Based on the NRC staff’s review of the licensee’s boron dilution analysis, the NRC staff finds the licensee has provided sufficient information to demonstrate that an undetected and uncorrected dilution from the TSrequired boron concentration to the calculated critical boron concentration is very unlikely. Based on its review of the boron analysis and enhancements to the operating procedures and operator training program, the NRC staff finds the licensee has satisfied Criterion 5. Therefore, in conjunction with the conservative assumptions used to establish the TS-required boron concentration and critical boron concentration, the boron dilution evaluation demonstrates that the underlying intent of 10 CFR 50.68(b)(1) is satisfied. 3.3 3.3.1 Legal Basis for the Exemption Authorized by Law This exemption results in changes to the operation of the plant by allowing the operation of the new dry fuel storage PO 00000 Frm 00063 Fmt 4703 Sfmt 4703 44945 facility and loading of the NUHOMS– 24PTH DSC. As stated above, 10 CFR 50.12 allows the NRC to grant exemptions from the requirements of 10 CFR Part 50. In addition, the granting of the licensee’s exemption request will not result in a violation of the Atomic Energy Act of 1954, as amended, or the intent of the Commission’s regulations. Therefore, the exemption is authorized by law. 3.3.2 No Undue Risk to Public Health and Safety The underlying purposes of 10 CFR 50.68(b)(1) is to ensure that adequate controls are in place to ensure that the handling and storage of fuel assemblies is conducted in a manner such that the fuel assemblies remain safely subcritical. Based on the NRC staff’s review of the licensee’s exemption request, the licensee has demonstrated that sufficient controls are in place to provide reasonable assurance that there is no undue risk to public health and safety given conservative assumption in the criticality analysis (criterion 1 above); surveillances periodically verify the boron concentration before and during loading and unloading (criterion 2 above); radiation monitoring equipment is used to detect excessive radiation and initiate appropriate protective actions (criterion 3 above); only fuel authorized by the ISFSI TS will be loaded and stored in the ISFSI (criterion 4 above); and boron dilution events have been analyzed, and there are sufficient monitoring capabilities and time for the licensee to identify and terminate a dilution event prior to achieving a critical boron concentration in the cask (criterion 5 above). Therefore, the NRC staff concluded that the underlying purpose of the rule has been satisfied and that there is no undue risk to public health and safety. 3.3.3 Consistent with Common Defense and Security This exemption results in changes to the operation of the plant by allowing the operation of the new dry fuel storage facility and loading of the NUHOMS– 24PTH DSC. This change to the fuel assembly storage and handling in the plant does not affect the national defense strategy because the national defense is maintained by resources (hardware or software or other) that are outside the plant and that have no direct relation to plant operation. In addition, loading spent fuel into the NUHOMS– 24PTH DSC in the SFP does not affect the ability of the licensee to defend the plant against a terrorist attack. Therefore, the common defense and E:\FR\FM\04AUN1.SGM 04AUN1 44946 Federal Register / Vol. 70, No. 149 / Thursday, August 4, 2005 / Notices security is not impacted by this exemption request. 3.3.4 Special Circumstances Pursuant to 10 CFR 50.12, ‘‘Specific Exemption,’’ the NRC staff reviewed the licensee’s exemption request to determine if the legal basis for granting an exemption had been satisfied. With regards to the six special circumstances listed in 10 CFR 50.12(a)(2), the NRC staff finds that the licensee’s exemption request satisfies 50.12(a)(2)(ii), ‘‘Application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule.’’ Specifically, the NRC staff concludes that since the licensee has satisfied the five criteria in Section 3.1 of this exemption, the application of the rule is not necessary to achieve its underlying purpose in this particular case. 3.4 Summary Based upon the review of the licensee’s exemption request to credit soluble boron during DSC loading, unloading, and handling in the HBRSEP2 SFP, the NRC staff concludes that pursuant to 10 CFR 50.12(a)(2) the licensee’s exemption request is acceptable. However, the NRC staff places the following limitations/ conditions on the approval of this exemption: 1. This exemption is limited to the loading, unloading, and handling of the DSC for only the TN NUHOMS–24PTH at HBRSEP2. 2. This exemption is limited to the loading, unloading, and handling in the DSC at HBRSEP2 of Westinghouse 15 x 15 fuel assemblies that had maximum initial, unirradiated U–235 enrichments corresponding to the TS limitations in LCO 1.2.1 for Amendment 8 to the NUHOMS –24PTH cask design. 4.0 Conclusion Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12(a), the exemption is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security. Also, special circumstances are present. Therefore, the Commission hereby grants CP&L an exemption from the requirements of 10 CFR 50.68(b)(1) for the loading, unloading, and handling of the components of the Transnuclear NUHOMS–24PTH dry cask storage system at HBRSEP2. However, since the licensee does not have an NRCapproved methodology for evaluating changes to the analyses or systems VerDate jul<14>2003 16:23 Aug 03, 2005 Jkt 205001 supporting this exemption request, the NRC staff’s approval of the exemption is restricted to those specific design and operating conditions described in the licensee’s February 22, 2005, exemption request. The licensee may not apply the 10 CFR 50.59 process for evaluating changes to specific exemptions. Any changes to the design or operation of (1) the dry cask storage system, (2) the spent fuel pool, (3) the fuel assemblies to be stored, (4) the boron dilution analyses, or (5) supporting procedures and controls, regardless of whether they are approved under the general Part 72 license or perceived to be conservative, will invalidate this exemption. Upon invalidation of the exemption, the licensee will be required to comply with NRC regulations prior to future cask loadings. Pursuant to 10 CFR 51.32, the Commission has determined that the granting of this exemption will not have a significant effect on the quality of the human environment (70 FR 43462). This exemption is effective upon issuance. Dated at Rockville, Maryland, this 27th day of July 2005. For the Nuclear Regulatory Commission. Ledyard B. Marsh, Director, Division of Licensing Project Management, Office of Nuclear Reactor Regulation. [FR Doc. E5–4147 Filed 8–3–05; 8:45 am] BILLING CODE 7590–01–P NUCLEAR REGULATORY COMMISSION [Docket Nos. 50–413 and 50–414] Duke Energy Corporation, et al.; Catawba Nuclear Station, Units 1 and 2; Notice of Consideration of Issuance of Amendment to Renewed Facility Operating Licenses, Proposed No Significant Hazards Consideration Determination, and Opportunity for a Hearing The U.S. Nuclear Regulatory Commission (NRC or the Commission) is considering issuance of amendments to Renewed Facility Operating License Nos. NPF–35 and NPF–52 issued to Duke Energy Corporation (the licensee) for operation of the Catawba Nuclear Station, Units 1 and 2, located in York County, South Carolina. The proposed amendment would revise the Technical Specification 3.7.9, ‘‘Standby Nuclear Service Water Pond (SNSWP),’’ temperature limit from 91.5 °F to 95 °F. Before issuance of the proposed license amendment, the Commission will have made findings required by the PO 00000 Frm 00064 Fmt 4703 Sfmt 4703 Atomic Energy Act of 1954, as amended (the Act), and the Commission’s regulations. The Commission has made a proposed determination that the amendment request involves no significant hazards consideration. Under the Commission’s regulations in Title 10 of the Code Of Federal Regulations (10 CFR), Section 50.92, this means that operation of the facility in accordance with the proposed amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety. As required by 10 CFR 50.91(a), the licensee has provided its analysis of the issue of no significant hazards consideration, which is presented below: 1. Does operation of the facility in accordance with the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated? No. This license amendment request proposes a change to the SNSWP [Standby Nuclear Service Water Pond] TS [Technical Specification] requirement for maximum temperature. The SNSWP is the safety related ultimate heat sink utilized by the NSWS [Nuclear Service Water System]. Neither the NSWS nor the SNSWP is capable of initiating an accident. Therefore, the probability of initiation of any accident cannot be affected. The technical evaluation provided in support of this amendment request demonstrated that with a maximum allowable SNSWP temperature of 95 °F as specified in SR 3.7.9.2, the environmental qualification limit for applicable safety related equipment is not reached and the peak containment pressure remains below the TS limit. This amendment request does not involve any change to previously analyzed dose analysis results. The accident of interest from a dose perspective is the Main Steam Line Break Accident. The dose release path during this accident is via steaming of the Reactor Coolant System through the steam generator power operated relief valves. The results of this accident have been reviewed with the revised SNSWP temperature limit and it has been determined that the Reactor Coolant System cooldown is terminated early enough such that the dose analysis results are not adversely impacted. Therefore, there is no increase in any accident consequences. 2. Does operation of the facility in accordance with the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated? No. This proposed amendment does not involve addition, removal, or modification of any plant system, structure, or component. This change will not affect the operation of E:\FR\FM\04AUN1.SGM 04AUN1

Agencies

[Federal Register Volume 70, Number 149 (Thursday, August 4, 2005)]
[Notices]
[Pages 44942-44946]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E5-4147]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-261]


Carolina Power and Light Company, H.B. Robinson Steam Electric 
Plant, Unit No. 2; Exemption

1.0 Background

    Carolina Power & Light Company (CP&L or the licensee) is the holder 
of Renewed Facility Operating License No. DPR-23, which authorizes 
operation of the H. B. Robinson Steam Electric Plant, Unit No. 2 
(HBRSEP2). The license provides, among other things, that the facility 
is subject to all rules, regulations, and orders of the Nuclear 
Regulatory Commission (NRC, the Commission) now or hereafter in effect.
    The facility consists of a pressurized-water reactor located in 
Darlington County, South Carolina.

2.0 Request/Action

    By letter dated February 22, 2005, as supplemented by letters dated 
May 10, July 6, and July 14, 2005, the licensee submitted a request for 
an exemption from the requirements of Title 10 of the Code of Federal 
Regulations (10 CFR) Section 50.68(b)(1) during the spent fuel pool 
(SFP) activities related to the underwater handling, loading, and 
unloading of the dry shielded canister (DSC) NUHOMS[supreg] -24PTH, as 
described in proposed Amendment No. 8 to Certificate of Compliance No. 
1004 listed in 10 CFR 72.214 at HBRSEP2.
    Section 50.68(b)(1) of 10 CFR sets forth the following requirement 
that must be met, in lieu of a monitoring system capable of detecting 
criticality events.

    Plant procedures shall prohibit the handling and storage at any 
one time of more fuel assemblies than have been determined to be 
safely subcritical under the most adverse moderation conditions 
feasible by unborated water.

    The licensee is unable to satisfy the above requirement for 
handling of the Transnuclear (TN) NUHOMS[supreg]-24PTH DSC authorized 
by 10 CFR Part 72 at HBRSEP2. Section 50.12(a) allows licensees to 
apply for an exemption from the requirements of 10 CFR Part 50 if the 
application of the regulation is not necessary to achieve the 
underlying purpose of the rule and special conditions are met. The 
licensee stated in the application that compliance with 10 CFR 
50.68(b)(1) is not necessary for handling the TN NUHOMS[supreg]-24PTH 
DSC system to achieve the underlying purpose of the rule.

3.0 Discussion

    Pursuant to 10 CFR 50.12, the Commission may, upon application by 
any interested person or upon its own initiative, grant exemptions from 
the requirements of 10 CFR Part 50 when (1) the exemptions are 
authorized by law, will not present an undue risk to public health or 
safety, and are consistent with the common defense and security; and 
(2) when special circumstances are present. Therefore, in determining 
the acceptability of the licensee's exemption request, the staff has 
performed the following regulatory, technical, and legal evaluations to 
satisfy the requirements of 10 CFR 50.12 for granting the exemption.

3.1 Regulatory Evaluation

    The HBRSEP2 Technical Specifications (TS) currently permit the 
licensee to store spent fuel assemblies in high-density storage racks 
in its SFP. In accordance with the provisions of 10 CFR 50.68(b)(4), 
the licensee takes credit for soluble boron for criticality control and 
ensures that the effective multiplication factor (keff) of 
the SFP does not exceed 0.95, if flooded with borated water. Section 
50.68(b)(4) of 10 CFR also requires that if credit is taken for soluble 
boron, the keff must remain below 1.0 (subcritical) if 
flooded with unborated water. However, the licensee is unable to 
satisfy the requirement to maintain the keff below 1.0 
(subcritical) with unborated water, which is also the requirement of 10 
CFR 50.68(b)(1), during cask handling operations in the SFP. Therefore, 
the licensee's request for exemption from 10 CFR 50.68(b)(1) proposes 
to permit the licensee to perform spent fuel loading, unloading, and 
handling operations related to dry cask storage without being 
subcritical under the most adverse moderation conditions feasible by 
unborated water.
    Title 10 of the Code of Federal Regulations, Part 50, Appendix A, 
``General Design Criteria (GDC) for Nuclear Power Plants,'' provides a 
list of the minimum design requirements for nuclear power plants. 
According to GDC 62, ``Prevention of criticality in fuel storage and 
handling,'' the licensee must limit the potential for criticality in 
the fuel handling and storage system by physical systems or processes. 
HBRSEP2 was licensed prior to the issuance of the GDC listed in 10 CFR 
50, Appendix A; therefore, GDC 62 is not directly applicable. However, 
HBRSEP2 has committed to a plant-specific version of the 1967 draft GDC 
as discussed in its Updated Final Safety Analysis Report (FSAR), 
Section 3.1.2. The comparable GDC is Criterion 66, ``Prevention of Fuel 
Storage Criticality,'' that states: ``Criticality in the new and spent 
fuel storage pits shall be prevented by physical systems or processes. 
Such means as geometrically safe configurations shall be emphasized 
over procedural controls.''
    Section 50.68 of 10 CFR Part 50, ``Criticality accident 
requirements,'' provides the NRC requirements for maintaining 
subcritical conditions in SFPs. Section 50.68 provides criticality 
control requirements that, if satisfied, ensure that an inadvertent 
criticality in the SFP is an extremely unlikely event. These 
requirements ensure that the licensee has appropriately conservative 
criticality margins during handling and storage of spent fuel. Section 
50.68(b)(1) states, ``Plant procedures shall prohibit the handling and 
storage at any one time of more fuel assemblies than have been 
determined to be safely subcritical under the most adverse moderation 
conditions feasible by unborated water.'' Specifically, 10 CFR 
50.68(b)(1) ensures that the licensee will maintain the pool in a 
subcritical condition during handling and storage operations without 
crediting the soluble boron in the SFP water.
    The licensee is authorized under general license to construct and 
operate

[[Page 44943]]

an Independent Spent Fuel Storage Installation (ISFSI) at HBRSEP2. The 
ISFSI permits the licensee to store spent fuel assemblies in large 
concrete dry storage casks. As part of its ISFSI loading campaigns, the 
licensee transfers spent fuel assemblies to a DSC in the cask pit area 
of the SFP. The licensee performed criticality analyses of the DSC 
fully loaded with fuel having the highest permissible reactivity and 
determined that a soluble boron credit was necessary to ensure that the 
DSC would remain subcritical in the SFP. Since the licensee is unable 
to satisfy the requirement of 10 CFR 50.68(b)(1) to ensure subcritical 
conditions during handling and storage of spent fuel assemblies in the 
pool with unborated water, the licensee identified the need for an 
exemption from the 10 CFR 50.68(b)(1) requirement to support DSC 
loading, unloading, and handling operations without being subcritical 
under the most adverse moderation conditions feasible by unborated 
water.
    The NRC staff evaluated the possibility of an inadvertent 
criticality of the spent nuclear fuel at HBRSEP2 during DSC loading, 
unloading, and handling. The NRC staff has established a set of 
acceptance criteria that, if met, satisfy the underlying intent of 10 
CFR 50.68(b)(1). In lieu of complying with 10 CFR 50.68(b)(1), the 
staff determined that an inadvertent criticality accident is unlikely 
to occur if the licensee meets the following five criteria:
    1. The cask criticality analyses are based on the following 
conservative assumptions:
    a. All fuel assemblies in the cask are unirradiated and at the 
highest permissible enrichment,
    b. Only 75 percent of the Boron-10 in the fixed poison panel 
inserts is credited,
    c. No credit is taken for fuel-related burnable absorbers, and
    d. The cask is assumed to be flooded with moderator at the 
temperature and density corresponding to optimum moderation.
    2. The licensee's ISFSI TS require the soluble boron concentration 
to be equal to or greater than the level assumed in the criticality 
analysis, and surveillance requirements necessitate the periodic 
verification of the concentration both prior to and during loading and 
unloading operations.
    3. Radiation monitors, as required by GDC 63, ``Monitoring Fuel and 
Waste Storage,'' are provided in fuel storage and handling areas to 
detect excessive radiation levels and to initiate appropriate safety 
actions.
    4. The quantity of other forms of special nuclear material, such as 
sources, detectors, etc., to be stored in the cask will not increase 
the effective multiplication factor above the limit calculated in the 
criticality analysis.
    5. Sufficient time exists for plant personnel to identify and 
terminate a boron dilution event prior to achieving a critical boron 
concentration in the DSC. To demonstrate that it can safely identify 
and terminate a boron dilution event, the licensee must provide the 
following:
    a. A plant-specific criticality analysis to identify the critical 
boron concentration in the cask based on the highest reactivity loading 
pattern.
    b. A plant-specific boron dilution analysis to identify all 
potential dilution pathways, their flowrates, and the time necessary to 
reach a critical boron concentration.
    c. A description of all alarms and indications available to 
promptly alert operators of a boron dilution event.
    d. A description of plant controls that will be implemented to 
minimize the potential for a boron dilution event.
    e. A summary of operator training and procedures that will be used 
to ensure that operators can quickly identify and terminate a boron 
dilution event.
    On March 23, 2005, the NRC issued Regulatory Issue Summary (RIS) 
2005-05, ``Regulatory Issues Regarding Criticality Analyses for Spent 
Fuel Pools and Independent Spent Fuel Storage Installations.'' In RIS 
2005-05, the NRC identified an acceptable methodology for demonstrating 
compliance with the 10 CFR 50.68(b)(1) requirements during cask 
loading, unloading, and handling operations in pressurized-water 
reactor SFPs. The NRC staff has determined that implementation of this 
methodology by licensees will eliminate the need to grant future 
exemptions for cask storage and handling evolutions. However, since the 
licensee submitted its exemption request prior to issuance of the RIS 
and identification of an NRC-acceptable methodology for compliance with 
the regulations, the NRC staff has determined that it is still 
appropriate to consider the exemption request.

3.2 Technical Evaluation

    In determining the acceptability of the licensee's exemption 
request, the staff reviewed three aspects of the licensee's analyses: 
(1) criticality analyses submitted to support the ISFSI license 
application and its exemption request, (2) boron dilution analysis, and 
(3) legal basis for approving the exemption. For each of the aspects, 
the staff evaluated whether the licensee's analyses and methodologies 
provide reasonable assurance that adequate safety margins are developed 
and can be maintained in the HBRSEP2 SFP during loading of spent fuel 
into canisters for dry cask storage.
3.2.1 Criticality Analyses
    For evaluation of the acceptability of the licensee's exemption 
request, the NRC staff reviewed the criticality analyses provided by 
the licensee in support of its ISFSI license application. First, the 
NRC staff reviewed the methodology and assumptions used by the licensee 
in its criticality analysis to determine if Criterion 1 was satisfied. 
The licensee stated that it took no credit in the criticality analyses 
for burnup or fuel-related burnable neutron absorbers. The licensee 
also stated that all assemblies were analyzed at the highest 
permissible enrichment. Additionally, the licensee stated that all 
criticality analyses for a flooded DSC were performed at temperatures 
and densities of water corresponding to optimum moderation conditions. 
Finally, the licensee stated that it credited 90 percent of the Boron-
10 content for the fixed neutron absorber in the DSC. NUREG-1536, 
``Standard Review Plan for Dry Cask Storage System,'' states that 
``[f]or a greater credit allowance [i.e., greater than 75 percent for 
fixed neutron absorbers] special, comprehensive fabrication tests 
capable of verifying the presence and uniformity of the neutron 
absorber are needed.'' As part of an amendment to the Part 72 license 
for the Transnuclear NUHOMS[supreg]-24PTH design, the NRC staff 
reviewed and accepted the results of additional data supplied by the 
manufacturer that demonstrated that a 90-percent credit for the fixed 
neutron absorbers was acceptable. These tests and corresponding results 
are detailed in Appendix P of the Standardized NUHOMS[supreg] FSAR. 
Therefore, for the purposes of this exemption, the staff finds a 90-
percent credit acceptable on the basis that it has previously been 
reviewed and approved by the NRC. Subsequently, based on its review of 
the criticality analyses and the information submitted in its exemption 
request, the NRC staff finds that the licensee has satisfied Criterion 
1.
    Second, the NRC staff reviewed the proposed HBRSEP2 ISFSI TS. The 
licensee's criticality analyses credit soluble boron for reactivity 
control during DSC loading, unloading, and handling operations. Since 
the boron concentration is a key safety component necessary for 
ensuring subcritical conditions in the pool, the licensee must have a 
conservative ISFSI TS capable of ensuring that sufficient soluble boron 
is present to perform its safety function. The ISFSI TS applicable

[[Page 44944]]

to the NUHOMS[supreg]-24PTH DSC, and attached to the Certificate of 
Compliance No. 1004, contain the requirements for the minimum soluble 
boron concentration as a function of fuel assembly class, DSC basket 
type, and corresponding assembly average initial enrichment values. In 
all cases, the boron concentration required by the ISFSI TS ensures 
that the keff will be below 0.95 for the analyzed loading 
configuration. Additionally, the licensee's ISFSI TS contain 
surveillance requirements that assure it will verify the boron 
concentration is above the required level both prior to and during DSC 
loading, unloading, and handling operations. Based on its review of the 
HBRSEP2 ISFSI TS, the NRC staff finds that the licensee has satisfied 
Criterion 2.
    Third, the NRC staff reviewed the HBRSEP2 Updated FSAR and the 
information provided by the licensee in its exemption request to ensure 
that it complies with GDC 63. GDC 63 requires that licensees have 
radiation monitors in fuel storage and associated handling areas to 
detect conditions that may result in a loss of residual heat removal 
capability and excessive radiation levels and initiate appropriate 
safety actions. As previously described, HBRSEP2 was licensed prior to 
the issuance of the GDC listed in 10 CFR 50, Appendix A; therefore, GDC 
63 is not directly applicable. However, HBRSEP2 has committed to a 
plant-specific version of the 1967 draft GDC as discussed in its 
Updated FSAR, Section 3.1.2. The comparable GDC is Criterion 18, 
``Monitoring Fuel and Waste Storage,'' that states the following: 
``Monitoring and alarm instrumentation shall be provided for fuel and 
waste storage and associated handling areas for conditions that might 
result in loss of capability to remove decay heat and detect excessive 
radiation levels.'' The NRC staff reviewed the HBRSEP2 Updated FSAR, 
plant-specific GDC, and exemption request to determine whether the 
licensee had provided sufficient information to demonstrate compliance 
with the intent of GDC 63. In its exemption request, the licensee 
stated that an area radiation monitor is located in the area of the 
SFP. Additionally, station procedures specify appropriate safety 
actions upon a high radiation alarm, including evacuation of local 
personnel, determination of cause, and determination of potential low 
water level in the SFP. In addition, personnel working in the area of 
the SFP wear individual, gamma-sensitive, electronic alarming 
dosimeters that provide an audible alarm should the dose or dose rate 
exceed pre-established setpoints. Based on its review of the exemption 
request, the HBRSEP2 Updated FSAR, and the licensee's plant-specific 
GDC, the NRC staff finds that the licensee has satisfied Criterion 3.
    Finally, as part of the criticality analysis review, the NRC staff 
evaluated the storage of non-fuel-related material in a DSC. The NRC 
staff evaluated the potential to increase the reactivity of a DSC by 
loading it with materials other than spent nuclear fuel and fuel 
debris. The approved contents for storage in the NUHOMS[supreg]-24PTH 
cask design are listed in the HBRSEP2 ISFSI TS Limiting Condition for 
Operation (LCO) 1.2.1 ``Fuel Specifications.'' This ISFSI TS LCO 
restricts the contents of the DSC to only fuels and non-fissile 
materials irradiated at HBRSEP2. As such, HBRSEP2 is prohibited from 
loading other forms of special nuclear material, such as sources, 
detectors, etc., in the DSC. Therefore, the NRC staff determined that 
the loading limitations described in the HBRSEP2 ISFSI TS will ensure 
that any authorized components loaded in the DSCs will not result in a 
reactivity increase. Based on its review of the loading restrictions, 
the NRC staff finds that the licensee has satisfied Criterion 4.3.2.2.
    Boron Dilution Analysis. Since the licensee's ISFSI application 
relies on soluble boron to maintain subcritical conditions within the 
DSCs during loading, unloading, and handling operations, the NRC staff 
reviewed the licensee's boron dilution analysis to determine whether 
appropriate controls, alarms, and procedures were available to identify 
and terminate a boron dilution accident prior to reaching a critical 
boron concentration.
    By letter dated October 25, 1996, the NRC staff issued a safety 
evaluation on licensing topical report WCAP-14416, ``Westinghouse Spent 
Fuel Rack Criticality Analysis Methodology.'' This safety evaluation 
specified that the following issues be evaluated for applications 
involving soluble boron credit: the events that could cause boron 
dilution, the time available to detect and mitigate each dilution 
event, the potential for incomplete boron mixing, and the adequacy of 
the boron concentration surveillance interval.
    The criticality analyses performed for the NUHOMS[supreg]-24PTH DSC 
are described in Section 6 of Appendix P of the FSAR for the 
Standardized NUHOMS[supreg] Horizontal Modular Storage System for 
Irradiated Nuclear Fuel. For this boron dilution evaluation, the 
licensee employed the same criticality analysis methods, models, and 
assumptions. These HBRSEP2 criticality calculations are based on the 
KENO V.a code. The calculations determined the minimum soluble boron 
concentration required to maintain subcriticality (keff < 
1.0) following a boron dilution event in a NUHOMS[supreg]-24PTH DSC 
loaded with fuel assemblies that bound the HBRSEP2 fuel designs 
(Westinghouse 15 x 15 fuel). Both intact and damaged fuel over the 
range of soluble boron concentrations permitted for various enrichments 
and basket types were evaluated. The results of these calculations for 
the bounding case indicate that subcriticality is maintained with 73 
percent or more of the minimum boron concentration levels required in 
the ISFSI TS for all basket types as a function of initial enrichment.
    Calculations were performed by the licensee to determine the time 
required to dilute the SFP such that the boron concentration is reduced 
from the NUHOMS[supreg] TS (required boron concentration for 
maintaining keff < 0.95) to a just subcritical boron 
concentration (keff < 1.0) for fuel loaded into a 
NUHOMS[supreg]-24PTH DSC.
    The HBRSEP2 SFP is a large structure filled with borated water that 
completely covers the spent fuel assemblies with more than 21 feet of 
water above the top of the fuel racks and the fuel cask. The cask lay 
down area is not separated by any structure from the remainder of the 
SFP. Thermal gradients generated by stored fuel and operation of the 
SFP cooling system will cause significant mixing within the pool. The 
licensee assumed that all unborated water introduced from any 
uncontrolled dilution source instantaneously mixes with the water in 
the SFP (i.e., no unborated water is lost prior to its mixing with 
borated water). The configuration of the pool and the mixing of the 
coolant provide reasonable assurance that this assumption is valid for 
low to moderate dilution flow rates.
    The volume of water in the SFP is 240,000 gallons. To reduce the 
boron concentration by a factor of 0.73 from the TS for keff 
<= 0.95 and approach a keff of 1.0 requires the addition of 
75,530 gallons of unborated water. Three examples of potential dilution 
sources were identified by the licensee: a 2-gpm flowrate from small 
failures or misaligned valves that could occur in the normal soluble 
boron control system or related systems, the failure of the 2-inch 
demineralized water header, and the maximum credible dilution event 
involving the rupture of a fire protection system header.
    To demonstrate that sufficient time exists for plant personnel to 
identify and terminate a boron dilution event, the licensee provided a 
description of

[[Page 44945]]

all alarms available to alert operators, and plant procedures, 
administrative controls, and training that will be implemented in 
response to an alarm. There is no automatic level control system for 
the SFP; therefore, any large, uncontrolled water addition would cause 
the SFP to overflow. However, a high level alarm in the control room 
would alert personnel of a potential boron dilution event when the 
water level reaches the high level setpoint.
    The highest uncontrolled dilution flow rate was determined to be 
the fire protection header on the SFP floor for fire hose station 104. 
As stated in the letter dated July 6, 2005, this fire protection header 
will be isolated during DSC loading and unloading to preclude this as a 
source of uncontrolled dilution to the SFP. The licensee has revised 
DSC loading and unloading procedures to include a requirement to close 
the fire protection system valve (FP-71) prior to placing fuel in the 
DSC during loading and prior to placing the loaded DSC back in the SFP 
during unloading. This change has resulted in the most limiting 
uncontrolled dilution source being identified as the assumed break of a 
2-inch demineralized water header, which could cause a dilution flow of 
approximately 103 gpm. No other single source has been identified that 
would exceed this dilution rate. Therefore, the time to reach a 
critical boron concentration, as provided by licensee, is estimated to 
be 755 minutes.
    In the case of the 103-gpm demineralized water pipe rupture, there 
would be no alarm from the demineralized water system. However, there 
would be available approximately 10 hours to isolate the leak once the 
SFP high level alarm was received. This analysis provides reasonable 
assurance that dilution flows leading to pool overflow would be 
detected and isolated well before the critical boron concentration 
could be reached from credible dilution sources.
    The licensee stated that plant procedures do allow for continued 
operation with the SFP high level alarm illuminated. The licensee 
stated that operating procedures had been revised to specify that, if 
the SPF high level alarm is illuminated and there is fuel in the DSC in 
the SFP, then continuous coverage to monitor the SFP water level will 
be required. A local level indicator is available in the SFP. The 
personnel providing continuous coverage when the SFP Hi Level Alarm is 
illuminated or inoperable can use this indication to detect possible 
dilution of the SFP. The available time before criticality by dilution 
is sufficient to allow identification and termination of any credible 
source of dilution.
    When fuel is loaded in the DSC in the SFP, boron analyses of the 
SFP water are required at least once every 48 hours per the TS. Small 
dilution flows may not be readily identified by level changes in the 
SFP due to operational leakage through the pool liner and the SFP 
cooling system. The licensee determined that a dilution flow of 2 gpm 
would require approximately 26 days to dilute the boron concentration 
of the SFP near to that calculated as the critical boron concentration. 
Therefore, the reduction in boron concentration due to a dilution 
flowrate of 2 gpm would be detected by the required boron concentration 
surveillance well before a significant dilution occurs.
    To ensure that operators are capable of identifying and terminating 
a boron dilution event during DSC loading, unloading, and handling 
operations, operator training will be conducted. This training will 
highlight the boron concentration requirements for loading the DSC, the 
potential for criticality should boron concentration levels decrease, 
and the need for timely mitigating activities if a boron dilution event 
occurs. Operators and other personnel involved in the dry fuel storage 
implementation will receive this new training prior to loading of the 
first DSC. Additionally, before each DSC loading evolution, the crew 
involved in performance of the work will receive a pre-job briefing, 
where the need for boron concentration control will be discussed.
    Based on the NRC staff's review of the licensee's boron dilution 
analysis, the NRC staff finds the licensee has provided sufficient 
information to demonstrate that an undetected and uncorrected dilution 
from the TS-required boron concentration to the calculated critical 
boron concentration is very unlikely. Based on its review of the boron 
analysis and enhancements to the operating procedures and operator 
training program, the NRC staff finds the licensee has satisfied 
Criterion 5.
    Therefore, in conjunction with the conservative assumptions used to 
establish the TS-required boron concentration and critical boron 
concentration, the boron dilution evaluation demonstrates that the 
underlying intent of 10 CFR 50.68(b)(1) is satisfied.

3.3 Legal Basis for the Exemption

3.3.1 Authorized by Law
    This exemption results in changes to the operation of the plant by 
allowing the operation of the new dry fuel storage facility and loading 
of the NUHOMS[supreg]-24PTH DSC. As stated above, 10 CFR 50.12 allows 
the NRC to grant exemptions from the requirements of 10 CFR Part 50. In 
addition, the granting of the licensee's exemption request will not 
result in a violation of the Atomic Energy Act of 1954, as amended, or 
the intent of the Commission's regulations. Therefore, the exemption is 
authorized by law.
3.3.2 No Undue Risk to Public Health and Safety
    The underlying purposes of 10 CFR 50.68(b)(1) is to ensure that 
adequate controls are in place to ensure that the handling and storage 
of fuel assemblies is conducted in a manner such that the fuel 
assemblies remain safely subcritical. Based on the NRC staff's review 
of the licensee's exemption request, the licensee has demonstrated that 
sufficient controls are in place to provide reasonable assurance that 
there is no undue risk to public health and safety given conservative 
assumption in the criticality analysis (criterion 1 above); 
surveillances periodically verify the boron concentration before and 
during loading and unloading (criterion 2 above); radiation monitoring 
equipment is used to detect excessive radiation and initiate 
appropriate protective actions (criterion 3 above); only fuel 
authorized by the ISFSI TS will be loaded and stored in the ISFSI 
(criterion 4 above); and boron dilution events have been analyzed, and 
there are sufficient monitoring capabilities and time for the licensee 
to identify and terminate a dilution event prior to achieving a 
critical boron concentration in the cask (criterion 5 above). 
Therefore, the NRC staff concluded that the underlying purpose of the 
rule has been satisfied and that there is no undue risk to public 
health and safety.
3.3.3 Consistent with Common Defense and Security
    This exemption results in changes to the operation of the plant by 
allowing the operation of the new dry fuel storage facility and loading 
of the NUHOMS[supreg]-24PTH DSC. This change to the fuel assembly 
storage and handling in the plant does not affect the national defense 
strategy because the national defense is maintained by resources 
(hardware or software or other) that are outside the plant and that 
have no direct relation to plant operation. In addition, loading spent 
fuel into the NUHOMS[supreg]-24PTH DSC in the SFP does not affect the 
ability of the licensee to defend the plant against a terrorist attack. 
Therefore, the common defense and

[[Page 44946]]

security is not impacted by this exemption request.
3.3.4 Special Circumstances
    Pursuant to 10 CFR 50.12, ``Specific Exemption,'' the NRC staff 
reviewed the licensee's exemption request to determine if the legal 
basis for granting an exemption had been satisfied. With regards to the 
six special circumstances listed in 10 CFR 50.12(a)(2), the NRC staff 
finds that the licensee's exemption request satisfies 50.12(a)(2)(ii), 
``Application of the regulation in the particular circumstances would 
not serve the underlying purpose of the rule or is not necessary to 
achieve the underlying purpose of the rule.'' Specifically, the NRC 
staff concludes that since the licensee has satisfied the five criteria 
in Section 3.1 of this exemption, the application of the rule is not 
necessary to achieve its underlying purpose in this particular case.

3.4 Summary

    Based upon the review of the licensee's exemption request to credit 
soluble boron during DSC loading, unloading, and handling in the 
HBRSEP2 SFP, the NRC staff concludes that pursuant to 10 CFR 
50.12(a)(2) the licensee's exemption request is acceptable. However, 
the NRC staff places the following limitations/conditions on the 
approval of this exemption:
    1. This exemption is limited to the loading, unloading, and 
handling of the DSC for only the TN NUHOMS[supreg]-24PTH at HBRSEP2.
    2. This exemption is limited to the loading, unloading, and 
handling in the DSC at HBRSEP2 of Westinghouse 15 x 15 fuel assemblies 
that had maximum initial, unirradiated U-235 enrichments corresponding 
to the TS limitations in LCO 1.2.1 for Amendment 8 to the 
NUHOMS[supreg] -24PTH cask design.

4.0 Conclusion

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12(a), the exemption is authorized by law, will not present an undue 
risk to the public health and safety, and is consistent with the common 
defense and security. Also, special circumstances are present. 
Therefore, the Commission hereby grants CP&L an exemption from the 
requirements of 10 CFR 50.68(b)(1) for the loading, unloading, and 
handling of the components of the Transnuclear NUHOMS[supreg]-24PTH dry 
cask storage system at HBRSEP2. However, since the licensee does not 
have an NRC-approved methodology for evaluating changes to the analyses 
or systems supporting this exemption request, the NRC staff's approval 
of the exemption is restricted to those specific design and operating 
conditions described in the licensee's February 22, 2005, exemption 
request. The licensee may not apply the 10 CFR 50.59 process for 
evaluating changes to specific exemptions. Any changes to the design or 
operation of (1) the dry cask storage system, (2) the spent fuel pool, 
(3) the fuel assemblies to be stored, (4) the boron dilution analyses, 
or (5) supporting procedures and controls, regardless of whether they 
are approved under the general Part 72 license or perceived to be 
conservative, will invalidate this exemption. Upon invalidation of the 
exemption, the licensee will be required to comply with NRC regulations 
prior to future cask loadings.
    Pursuant to 10 CFR 51.32, the Commission has determined that the 
granting of this exemption will not have a significant effect on the 
quality of the human environment (70 FR 43462). This exemption is 
effective upon issuance.

    Dated at Rockville, Maryland, this 27th day of July 2005.

    For the Nuclear Regulatory Commission.
Ledyard B. Marsh,
Director, Division of Licensing Project Management, Office of Nuclear 
Reactor Regulation.
[FR Doc. E5-4147 Filed 8-3-05; 8:45 am]
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