STP Nuclear Operating Company; South Texas Project, Units 1 and 2, 33161-33165 [2017-15136]

Agencies

• NUCLEAR REGULATORY COMMISSION

[Federal Register Volume 82, Number 137 (Wednesday, July 19, 2017)]
[Notices]
[Pages 33161-33165]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-15136]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-498 and 50-499; NRC-2016-0092]


STP Nuclear Operating Company; South Texas Project, Units 1 and 2

AGENCY: Nuclear Regulatory Commission.

ACTION: Exemption; issuance.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is granting 
exemptions from certain portions of the acceptance criteria for 
emergency core cooling, and the general design criteria for emergency 
core cooling, containment heat removal, and atmosphere cleanup for the 
use of a risk-informed analysis to evaluate the effects of debris in 
containment following a loss-of-coolant accident (LOCA) for the South 
Texas Project (STP), Units 1 and 2, located in Matagorda County, Texas, 
Docket Nos. 50-498 and 50-499, respectively. The exemptions are in 
response to a request dated June 19,

[[Page 33162]]

2013, from the STP Nuclear Operating Company (STPNOC, the licensee) 
related to STPNOC's proposed approach to resolve a generic safety 
concern for pressurized water reactors (PWRs) associated with potential 
clogging of emergency core cooling and containment spray system 
strainers during certain design basis events.

DATES: The exemption was issued on July 11, 2017.

ADDRESSES: Please refer to Docket ID NRC-2016-0092 when contacting the 
NRC about the availability of information regarding this document. You 
may obtain publicly-available information related to this document 
using any of the following methods:
     Federal Rulemaking Web site: Go to https://www.regulations.gov and search for Docket ID NRC-2016-0092. Address 
questions about NRC dockets to Carol Gallagher; telephone: 301-415-
3463; email: Carol.Gallagher@nrc.gov. For technical questions, contact 
the individual listed in the FOR FURTHER INFORMATION CONTACT section of 
this document.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may obtain publicly-available documents online in the 
ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``ADAMS Public Documents'' and 
then select ``Begin Web-based ADAMS Search.'' For problems with ADAMS, 
please contact the NRC's Public Document Room (PDR) reference staff at 
1-800-397-4209, 301-415-4737, or by email to pdr.resource@nrc.gov. For 
the convenience of the reader, the ADAMS accession numbers are provided 
in a table in the ``Availability of Documents'' section of this 
document.
     NRC's PDR: You may examine and purchase copies of public 
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 
Rockville Pike, Rockville, Maryland 20852.

FOR FURTHER INFORMATION CONTACT: Lisa Regner, Office of Nuclear Reactor 
Regulation, U.S. Nuclear Regulatory Commission, Washington DC 20555-
0001; telephone: 301-415-1906, email: Lisa.Regner@nrc.gov.

SUPPLEMENTARY INFORMATION:

I. Background

    The licensee is the holder of Facility Operating License Nos. NPF-
76 and NPF-80, which authorize operation of the STP Units 1 and 2, 
respectively. The licenses provide, among other things, that the 
facility is subject to all rules, regulations, and orders of the NRC 
now or hereafter in effect. The facility consists of two PWRs located 
in Matagorda County, Texas.
    In 1996, the NRC identified Generic Safety Issue (GSI)-191 
associated with the effects of debris accumulation on PWR sump 
performance during design-basis accidents. As part of the actions to 
resolve GSI-191, the NRC issued Generic Letter (GL) 2004-02, 
``Potential Impact of Debris Blockage on Emergency Recirculation during 
Design Basis Accidents at Pressurized-Water Reactors,'' dated September 
13, 2004, to holders of operating licenses for PWRs. In GL 2004-02, the 
NRC staff requested that licensees perform an evaluation of their 
emergency core cooling systems (ECCS) and containment spray system 
(CSS) recirculation functions considering the potential for debris-
laden coolant to be circulated by the ECCS and the CSS after a LOCA or 
high energy line break inside containment and, if appropriate, take 
additional actions to ensure system function. The GL required that 
licensees provide a written response to the NRC, pursuant to section 
50.54(f) of title 10 of the Code of Federal Regulations (10 CFR), 
describing the results of their evaluation and any modifications made, 
or planned, to ensure the ECCS and CSS remain functional.

II. Request/Action

    By letter dated June 19, 2013, as supplemented by letters dated 
August 20, 2015, and April 13, 2016, STPNOC submitted requests for 
exemptions pursuant to 10 CFR 50.12, ``Specific exemptions,'' from the 
requirements of 10 CFR 50.46, ``Acceptance criteria for emergency core 
cooling systems for light-water nuclear power reactors,'' and 10 CFR 
part 50, appendix A, General Design Criterion (GDC) 35, ``Emergency 
core cooling,'' GDC 38, ``Containment heat removal,'' and GDC 41, 
``Containment atmosphere cleanup,'' to use a risk-informed methodology 
instead of the traditional deterministic methodology, to resolve the 
concerns associated with GSI-191 and respond to GL 2004-02.
    Specifically, the licensee requested an exemption from 10 CFR 
50.46(a)(1)(i), which, in part, requires ECCS cooling performance to be 
calculated in accordance with an acceptable evaluation model, as 
described in 10 CFR 50.46(a)(1), for postulated LOCAs of different 
sizes, locations and other properties sufficient to provide assurance 
that the most severe LOCAs are evaluated in order to demonstrate that 
acceptance criteria in 10 CFR 50.46(b) are met. The NRC staff 
interprets 10 CFR 50.46(a)(1) requirement to calculate ECCS performance 
for ``other properties'' as requiring licensees to consider the impacts 
of debris generation and transport in containment. The most significant 
form of debris in nuclear power reactor containments is piping and 
component insulation that becomes debris during LOCAs, is transported 
and accumulates in the sumps, and clogs the sumps strainers, thus 
creating resistance to coolant flow. Fibrous debris from this 
insulation can also enter the reactor core and directly impede heat 
transfer from the fuel to the coolant. The licensee also requested 
exemptions from GDC 35, which contain ECCS performance requirements, 
and GDCs 38 and 41, which respectively set performance requirements for 
reactor containment heat removal following a LOCA and for containment 
atmosphere cleanup following postulated accidents.
    The approval of a risk-informed methodology would require 
exemptions from 10 CFR 50.46(a)(1)(i) and GDCs 35, 38, and 41 because 
the NRC has interpreted these regulations as requiring a deterministic 
approach and bounding calculation to show compliance with ECCS and CSS 
performance criteria in 10 CFR 50.46(b) and GDCs 35, 38 and 41. 
Issuance of exemptions is an appropriate means to grant relief from the 
use of a deterministic approach to show compliance with these 
requirements.
    The licensee's 10 CFR 50.46 deterministic analysis considered the 
debris in containment and demonstrated that the debris loading could 
prevent acceptable ECCS and CSS operation and core cooling for certain 
pipe ruptures. Based on its analysis, the licensee concluded that the 
amount of debris in the STP containment would need to be reduced to 
demonstrate compliance with 10 CFR 50.46 criteria using a deterministic 
analysis for certain large-break LOCA sizes because, for those breaks, 
the plant-specific testing threshold for generation and transport of 
debris was exceeded.
    Additionally, the licensee's deterministic thermal-hydraulic (TH) 
analysis could not show that hot-leg LOCAs greater than 16 inches could 
maintain adequate cooling. While not all large-break hot-leg LOCAs 
resulted in a loss of in-core cooling due to strainer blockage, the 
licensee categorized all hot-leg breaks greater than 16 inches as 
assumed to fail in order to simplify the TH analysis.
    The licensee requested exemptions from the requirement to use a 
deterministic analysis for specific scenarios of LOCA breaks producing 
and transporting debris in excess of the plant-specific tested debris 
limits and

[[Page 33163]]

for large hot-leg breaks. Since it determined that the probability of 
consequences from debris effects is very low, the licensee requested an 
exemption to use a risk-informed analysis to show adequate assurance of 
ECCS and CSS functionality, in accordance with the criteria in 
Regulatory Guide (RG) 1.174, ``An Approach for Using Probabilistic Risk 
Assessment in Risk-Informed Decisions on Plant-Specific Changes to the 
Licensing Basis.'' The RG 1.174 was developed in consideration of the 
Commission's Policy Statements on safety goals and the use of 
probabilistic risk assessment methods in nuclear regulatory activities 
(``Safety Goals for the Operations of Nuclear Power Plants; Policy 
Statement,'' August 4, 1986, 51 FR 30028; and ``Use of Probabilistic 
Risk Assessment Methods in Nuclear Activities; Final Policy 
Statement,'' August 16, 1995, 60 FR 42622, respectively). Therefore, RG 
1.174 provides an acceptable method for licensees and NRC staff to use 
in assessing the impact of licensing basis changes when the licensee 
chooses to use risk information.
    The GDC 35, in part, requires that the ECCS safety system functions 
adequately to transfer heat from the reactor core following a LOCA and 
in the presence of a worst single failure, at a rate such that (a) fuel 
and clad damage that could interfere with continued effective core 
cooling is prevented and (b) clad metal-water reactor is limited to 
negligible amounts. The licensee stated in its submittal that the 
function of the ECCS emergency sump is assumed to fail for debris that 
exceeds the amount determined in acceptable plant-specific testing. 
Failure of the sump and strainers result in loss of cooling to the 
core. The licensee requested an exemption from the deterministic 
requirements of GDC 35 to use a risk-informed approach to show ECCS 
function for those LOCA breaks that exceed the plant-specific testing 
debris threshold, and for large hot-leg breaks. The use of a risk-
informed analysis, in accordance with the criteria in RG 1.174, would 
allow the licensee to show that the risk from debris effects is very 
low.
    The GDC 38 requires containment heat removal, rapid reduction of 
containment pressure and temperature, and maintenance of pressure and 
temperature at an acceptably low level following a LOCA, and in the 
presence of a single failure, to preserve containment function. The 
STPNOC proposed that an exemption be granted from the deterministic 
requirements in GDC 38, for those LOCA breaks that exceed the plant-
specific testing debris threshold. Current STP design basis 
calculations are based on the reactor containment fan coolers 
functioning in conjunction with the CSS and ECCS, both of which can be 
affected by debris. Using deterministic assumptions, STPNOC's analysis 
and testing does not assure that the emergency sump strainers will be 
available to support the CSS and ECCS function considering the effects 
of debris produced by those breaks that can generate and transport 
debris amounts greater than the plant-specific testing threshold. The 
licensee requested an exemption from the deterministic requirements of 
GDC 38 to use a risk-informed analysis, in accordance with the criteria 
in RG 1.174, to show that the risk from debris effects is very low.
    The GDC 41, in part, requires containment atmosphere cleanup to 
control substances that may be released into the reactor containment, 
to reduce the concentration and quality of fission products released to 
the environment following postulated accidents, and to control the 
concentration of hydrogen or oxygen and other substances in the 
containment atmosphere following postulated accidents, assuming a 
single failure. The licensee stated that using deterministic 
assumptions, STPNOC's analysis and testing cannot demonstrate that the 
emergency sump strainers will be available to support the CSS function 
considering the effects of debris produced and transported by breaks 
not bounded by acceptable plant-specific testing. The licensee 
requested an exemption from the deterministic requirements of GDC 41 to 
use a risk-informed analysis, in accordance with the criteria in RG 
1.174, to show that the risk from debris effects is very low.

III. 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. Under 10 CFR 
50.12(a)(2)(ii), special circumstances are present ``when 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.''
    The licensee proposed to use a risk-informed methodology instead of 
a deterministic approach to account for the effects of debris in 
containment for portions of the LOCA analysis applicable to breaks that 
exceed the STP plant-specific debris testing threshold and large hot-
leg piping breaks. The STPNOC methodology, termed Risk over 
Deterministic, or RoverD, divides the loss of core cooling design-basis 
analysis into two portions: the ``deterministic analysis'' and the 
``risk-informed analysis.'' The risk-informed analysis is used by the 
licensee for breaks that generate and transport debris exceeding the 
plant-specific testing threshold. These breaks result in low density 
fiber glass fiber fines estimated to arrive in the ECCS sump post-LOCA 
in amounts that are equal to or greater than the amount of fines used 
in acceptable strainer testing. The acceptable limit was determined 
using testing methods intended to determine the maximum ECCS strainer 
head loss for the tested condition.
    Also, the licensee evaluated the in-core TH aspects of fibrous 
debris to prevent adequate fuel cooling, finding that hot-leg breaks 
greater than 16 inches have the potential to prevent adequate in-core 
cooling. In order to simplify its TH evaluation, the licensee assumed 
that all large breaks greater than 16 inches in the hot-leg will result 
in the loss of the cooling function. For ECCS and CSS analyses other 
than the postulated large-break LOCAs in the hot-leg piping in 
containment and those breaks that exceed the STP plant-specific testing 
limit, STPNOC applied a deterministic methodology. If the exemptions 
were granted for these postulated breaks, the requirement to use a 
deterministic methodology for all other postulated LOCA breaks would 
continue to apply.

A. Special Circumstances

    Under the regulations in 10 CFR 50.12, the Commission may grant 
exemptions from the requirements of 10 CFR part 50 provided certain 
findings are made; namely, that special circumstances are present, the 
exemptions present no undue risk to public health and safety, the 
exemptions are consistent with the common defense and security, and the 
exemptions are authorized by law. The exemptions would allow the 
licensee to use a risk-informed methodology to show compliance with 10 
CFR 50.46(b), and GDCs 35, 38, and 41, specifically for the analyses of 
debris in containment impacting emergency cooling function during 
postulated large-break hot-leg LOCAs and those breaks that exceed the 
plant-specific testing threshold.
    The licensee requested exemptions citing the special circumstances 
criteria

[[Page 33164]]

of 10 CFR 50.12(a)(2)(ii), because compliance 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. The 
licensee stated that these special circumstances are common to all of 
the requested exemptions.
    The licensee stated that an objective of each of the regulations 
for which an exemption is proposed is to maintain low risk to the 
public health and safety through the adequate functioning of the ECCS 
and CSS safety systems. These systems must be supported by adequate 
functioning of the containment sumps. The regulations in 10 CFR 
50.46(a)(1)(i) and GDCs 35, 38, and 41 are met when the licensee is 
able to demonstrate, using a bounding calculation or other 
deterministic method that the ECCS and CSS are capable of functioning 
during design basis events. The STPNOC stated that its risk-informed 
analysis to show adequate functioning of ECCS and CSS considering the 
impacts of debris during certain LOCA events demonstrates that the risk 
of failure of these systems is very small. The licensee stated that 
special circumstances exist because the underlying intent of the 
regulations, to ensure adequate protection of public health and safety 
is met when applying a risk-informed approach to address GSI-191 and 
respond to GL 2004-02. Further, it states that the risk-informed 
approach is consistent with RG 1.174, and supports operation of those 
functions with a high degree of reliability. Thus, the licensee 
concludes that the underlying intent of each regulation is met and the 
special circumstances described in 10 CFR 50.12(a)(2)(ii) apply to each 
of the exemptions proposed by STPNOC.
    The NRC staff evaluated the STPNOC submittal and supplements, and 
discussed the details of its evaluation of the risk-informed approach 
in an NRC safety evaluation available in ADAMS under Accession No. 
ML17019A001. Although 10 CFR 50.46(a)(1) requires a deterministic 
approach, the GDCs do not specify that a risk-informed methodology may 
not be used to show compliance; however, because the NRC has 
interpreted each of these regulations as requiring a deterministic 
approach, an exemption is an appropriate means to grant the licensee 
relief to use an alternative approach. The underlying purpose of each 
regulation is to protect public health and safety in the event of a 
LOCA by establishing criteria for emergency core cooling, containment 
cooling and containment atmosphere cleanup system performance. In its 
safety evaluation, the NRC staff concluded, in part, that the licensee 
adequately demonstrated that the change in risk attributable to debris 
in postulated hot-leg LOCAs greater than 16 inches, and those breaks 
that exceed the plant specific threshold, is very small. The NRC staff 
also concluded that the licensee's proposal for demonstrating 
compliance with the ECCS and CSS performance requirements meet the risk 
acceptance guidelines in RG 1.174 because the approach is related to a 
permissible exemption request, is consistent with defense-in-depth 
philosophy, maintains sufficient safety margins, results in a small 
increase in risk, and the impact of this approach is monitored by the 
licensee using performance measurement strategies. Therefore, the 
licensee's use of the risk-informed analysis to consider the impacts of 
debris meets the underlying requirements of 10 CFR 50.46 and GDCs 35, 
38, and 41, to ensure that a licensee demonstrates that the ECCS and 
CSS will provide adequate cooling for the reactor core and containment, 
as well as containment atmosphere cleanup following postulated design-
basis accidents.
    Based on the above, the NRC staff concludes that special 
circumstances under 10 CFR 50.12(a)(2)(ii) exist because compliance 
with the deterministic requirements of 10 CFR 50.46(a)(1)(i), and GDCs 
35, 38, and 41 is not necessary to achieve the underlying purpose of 
each rule.

B. The Exemption Presents No Undue Risk to Public Health and Safety

    The provisions of 10 CFR 50.46 and GDCs 35, 38, and 41 establish 
criteria for the emergency core cooling, containment cooling, and 
containment atmosphere cleanup system performance. As part of the 
amendment requests, the STPNOC submitted exemption requests to change 
its design-basis analysis specified in the Updated Final Safety 
Analysis Report (UFSAR) to use new risk-informed and deterministic 
methodologies to specifically account for the impacts of debris in 
containment. The licensee justified its use of the risk-informed 
approach by stating that the proposed risk-informed approach meets the 
key principles in RG 1.174 in that it is consistent with defense-in-
depth philosophy, maintains sufficient safety margins, results in a 
small increase in risk, and is monitored by the licensee using 
performance measurement strategies.
    Additionally, the licensee stated that the proposed exemptions to 
use the risk-informed method are consistent with Key Principle 1 in RG 
1.174 that requires a proposed change to the licensing basis (or 
amendment) to meet current regulations unless the change is explicitly 
related to a requested exemption. The licensee's probabilistic risk 
analysis results provided by the licensee and evaluated by the NRC 
staff in its safety evaluation, showed that the increase in risk 
associated with debris generation and transport on ECCS and CSS 
function following postulated LOCAs is very low, in accordance with the 
criteria in RG 1.174.
    The NRC staff concluded that the risk is consistent with the 
guidance in RG 1.174 and with the Commission policy statements on 
safety goals and the use of probabilistic risk assessment methods in 
nuclear regulatory activities; therefore, the requested exemption 
presents no undue risk to public health and safety.

C. The Exemption Is Consistent With the Common Defense and Security

    The requested exemptions to use a risk-informed methodology allow 
STPNOC to resolve a generic safety concern for PWRs associated with 
potential clogging of the ECCS and CSS strainers during certain design-
basis events. The change is adequately controlled by safety acceptance 
criteria and technical specification requirements and is not related to 
security issues. Because the common defense and security is not 
impacted by the exemption, the exemption is consistent with the common 
defense and security.

D. The Exemptions Are Authorized by Law

    The exemptions to use a risk-informed methodology allow STPNOC to 
show compliance with 10 CFR 50.46(a)(1)(i), and GDCs 35, 38, and 41, 
when considering debris in containment generated and transported during 
postulated hot-leg LOCA breaks greater than 16 inches, and those breaks 
that exceed the plant-specific testing threshold. These regulations 
were promulgated under, and are consistent with the Commission's 
authority under Section 161 of the Atomic Energy Act. Because the 
application of a risk-informed methodology to show compliance with 10 
CFR 50.46, and GDC 35, 38, and 41 would not violate the Atomic Energy 
Act of 1954, as amended, or the Commission's regulations, the 
exemptions are authorized by law provided all requisite findings are 
made.

[[Page 33165]]

E. Environmental Considerations

    Pursuant to 10 CFR 51.21, ``Criteria for and identification of 
licensing and regulatory actions requiring environmental assessments,'' 
the NRC has prepared an Environmental Assessment (EA) summarizing the 
findings of its review of the environmental impacts of the proposed 
action under the National Environmental Policy Act. The NRC staff 
determined that special circumstances under 10 CFR 51.21 exist to 
warrant preparation of an EA because STP is the pilot plant to propose 
a risk-informed approach to resolve GSI-191 as recognized in Staff 
Requirement Memorandum SECY-12-0093, ``Closure Options for Generic 
Safety Issue-191, Assessment of Debris Accumulation on Pressurized-
Water Reactor Sump Performance,'' dated December 14, 2012. Because this 
is the first approval of a risk-informed approach, the NRC staff 
considered preparations of an EA to be a prudent course of action that 
would further the purposes of the National Environmental Policy Act. 
Based on its review, the NRC concluded that an environmental impact 
statement is not required and that the proposed action will have no 
significant impact on the environment.
    The NRC published a final EA on the proposed action in the Federal 
Register on May 9, 2017 (82 FR 21568).

IV. Conclusions

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12, exemptions are authorized by law, will not present an undue risk 
to the public health and safety, are consistent with the common defense 
and security, and special circumstances are present pursuant to 10 CFR 
50.12(a)(2)(ii). Therefore, the NRC hereby grants STPNOC a one-time 
exemption from 10 CFR 50.46(a)(1), and 10 CFR part 50, appendix A, GDCs 
35, 38, and 41 to use a risk-informed methodology in lieu of a 
deterministic methodology to show conformance with the ECCS and CSS 
performance criteria accounting for debris in containment for large-
break hot-leg LOCAs and those breaks that exceed the plant-specific STP 
testing threshold.

V. Availability of Documents

    The documents identified in the following table are available for 
public inspection through the NRC's Agencywide Documents Access and 
Management System (ADAMS).

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                                                               ADAMS
                  Title                        Date        accession No.
------------------------------------------------------------------------
NRC Generic Letter 2004-02, Potential          9/13/2004     ML042360586
 Impact of Debris Blockage on Emergency
 Recirculation During Design Basis
 Accidents at Pressurized-Water Reactors
STPNOC letter to NRC, Revised STP Pilot        6/19/2013     ML131750250
 Submittal and Requests for Exemptions                         (Package)
 and License Amendment for a Risk-
 Informed Approach to Resolving Generic
 Safety Issue (GSI)-191.................
STPNOC letter to NRC, Supplement 2 to            8/20/15     ML15246A125
 STP Pilot Submittal and Requests for                          (Package)
 Exemptions and License Amendment for a
 Risk-Informed Approach to Address
 Generic Safety Issue (GSI)-191 and
 Respond to Generic Letter (GL) 2004-02.
STPNOC letter to NRC, South Texas              4/13/2016     ML16111B204
 Project, Units 1 and 2--Revision to
 Proposed Exemption to 10 CFR 50.46
 Described in Pilot Submittal and
 Requests for Exemptions and License
 Amendment for a Risk-Informed Approach
 to Address Generic Safety Issue (GSI)-
 191 and Respond to Generic Letter (GL)
 2004-02................................
Regulatory Guide 1.174, Revision 2, ``An          5/2011     ML100910006
 Approach for Using Probabilistic Risk
 Assessment in Risk-Informed Decisions
 on Plant-Specific Changes to the
 Licensing Basis''......................
NRC letter to STPNOC, South Texas              7/11/2017     ML17019A001
 Project, Units 1 and 2--Issuance of                           (Package)
 Amendment Nos. 212 and 198--Risk-
 Informed Approach to Resolve Generic
 Safety Issue-191 (includes Safety
 Evaluation)............................
Commission SRM-SECY-12-0093, Staff            12/14/2012     ML12349A378
 Requirements--SECY-12-0093--Closure
 Options for Generic Safety Issue--191,
 Assessment of Debris Accumulation on
 Pressurized-Water Reactor Sump
 Performance............................
NRC Letter to STPNOC, South Texas              5/02/2017     ML16278A598
 Project, Units 1 and 2--Letter,
 Environmental Assessment and Finding of
 No Significant Impact, Revise Licensing
 Basis as Documented in the UFSAR and
 Request for Exemptions, Risk-Informed
 approach to Address GSI[dash]191.......
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    Dated at Rockville, Maryland, this 11th day of July 2017.
    For the Nuclear Regulatory Commission.
Eric J. Benner,
Deputy Director, Division of Operating Reactor Licensing, Office of 
Nuclear Reactor Regulation.
[FR Doc. 2017-15136 Filed 7-18-17; 8:45 am]
 BILLING CODE 7590-01-P