Entergy Operations, Inc., River Bend Station, Unit 1; Exemption, 53482-53483 [2013-21103]

Agencies

• NUCLEAR REGULATORY COMMISSION

[Federal Register Volume 78, Number 168 (Thursday, August 29, 2013)]
[Notices]
[Pages 53482-53483]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-21103]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-458; NRC-2013-0190]


Entergy Operations, Inc., River Bend Station, Unit 1; Exemption

1.0 Background

    Entergy Operations Inc. (Entergy, the licensee) is the holder of 
Facility Operating License No. NPF-47, which authorizes operation of 
the River Bend Station, Unit 1 (RBS). The license provides, among other 
things, that the facility is subject to all rules, regulations, and 
orders of the U.S. Nuclear Regulatory Commission (NRC) now or hereafter 
in effect.
    The facility consists of a boiling-water reactor located in West 
Feliciana Parish, Louisiana.

2.0 Request/Action

    Part 50 of Title 10 of the Code of Federal Regulations (10 CFR), 
appendix J, ``Primary Reactor Containment Leakage Testing for Water-
Cooled Power Reactors,'' requires that components which penetrate 
containment be periodically leak tested at the ``Pa,'' 
defined as the ``calculated peak containment internal pressure related 
to the design basis accident specified either in the technical 
specification or associated bases.'' In October 2011, Entergy was 
contacted by the NRC concerning the station's use of the appendix J 
definition of Pa. The NRC noted a conflict between Entergy's 
interpretation of that definition of Pa and the literal 
reading of the definition of Pa in the regulations. Entergy 
stated it was defining Pa based on the long-term calculated 
pressure peak for the containment as a whole and not on the short-term 
localized pressure spike in wetwell.
    By letter dated August 23, 2012 (Agencywide Documents Access and 
Management System (ADAMS) Accession No. ML12241A250), Entergy submitted 
a request for an exemption from the definition of the Pa as 
stated in 10 CFR part 50, appendix J, and substitute an alternate 
definition. The value of Pa is determined by calculating the 
pressure response in containment over time after a main steam line 
break. The original containment analysis for RBS had determined 
Pa to be 7.6 pounds per square inch gauge (psig). In July 
1999, RBS submitted a license amendment request to increase the 
licensed thermal power of the station by 5 percent from 2,894 megawatts 
thermal (MWth) to 3,039 MWth. As part of the extended power uprate 
review, new calculations were performed and determined that a localized 
pressure spike in the wetwell occurs within a few seconds of the 
accident and with a pressure peak at 9.3 psig. However, the localized 
pressure in the wetwell quickly drops by several psig as the pressure 
equalizes throughout containment. This calculation also determined that 
the long-term peak containment pressure is 3.6 psig. To avoid a large 
number of procedure changes, which would be required if the value was 
changed, RBS elected to maintain Pa at the original (pre-
extended power uprate) value of 7.6 psig, which is conservative to the 
calculated long-term peak value of 3.6 psig. The exemption would allow 
Entergy to continue to use the previously calculated value of 7.6 psig 
for Pa for RBS instead of the localized pressure spike in 
the wetwell calculated value of 9.3 psig.
    The NRC staff has concluded that the use of the alternate 
definition for Pa meets the intent of 10 CFR part 50, 
appendix J because it provides testing of the primary containment 
parameters at a pressure that would exist throughout containment over 
the long term following a design basis accident.

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. The staff accepts the 
licensee's determination that an exemption would be required to 
continue to use the alternate definition of Pa from that 
defined in 10 CFR part 50, appendix J.
    The NRC staff examined the licensee's rationale to support the 
exemption request and concluded that the use the value of 7.6 psig for 
Pa would meet the underlying purpose of 10 CFR part 50, 
appendix J. Supporting the use of this alternate value is:
    (1) The time for the pressure spike to occur and fall to 
equilibrium is 6 seconds, which is not sufficient time to release 
source terms from the core,

[[Page 53483]]

    (2) the pressure spike is also localized to the wetwell area which 
makes up roughly 10 percent of containment,
    (3) the number of containment penetrations in this area is limited. 
Therefore, the current Pa value of 7.6 psig meets the intent 
of 10 CFR part 50, appendix J by bounding the peak bulk containment 
pressure (3.6 psig) and assuring that leakage through the primary 
containment does not exceed allowable leakage rate values,
    (4) the calculated peak bulk containment pressure is 3.6 psig so 
the Technical Specification (TS) value of 7.6 is conservative for the 
use of determining containment leakage, and
    (5) this request is consistent with the determination that the NRC 
staff has reached for other licensees under similar conditions based on 
the same considerations.
    The application for exemption may be examined, and/or copied for a 
fee, at the NRC's Public Document Room, located at One White Flint 
North, 11555 Rockville Pike (first floor), Rockville, Maryland 20852. 
Publicly available records will be accessible electronically from the 
ADAMS Public Library component on the NRC's Web site, https://www.nrc.gov (the Electronic Reading Room).
    Therefore, the NRC staff concludes that requesting exemption under 
the special circumstances of 10 CFR 50.12(a)(2)(ii) is appropriate and 
that the alternate definition of Pa may be used for the 
appendix J testing.

Authorized by Law

    This exemption would allow Entergy to use a Pa value of 
7.6 psig for appendix J testing at the RBS as discussed above. As 
stated above, 10 CFR 50.12 allows the NRC to grant exemptions from the 
requirements of 10 CFR part 50, appendix J. The NRC staff has 
determined that granting of the licensee's proposed exemption is in 
accordance with the Atomic Energy Act of 1954, as amended, or the 
Commission's regulations. Therefore, the exemption is authorized by 
law.

No Undue Risk to Public Health and Safety

    The underlying purposes of 10 CFR part 50, appendix J are stated in 
section (I) ``Introduction.'' The purpose is to conduct tests to assure 
that a) leakage through the primary reactor containment does not exceed 
allowable leakage rate values and b) to conduct periodic surveillance 
of reactor containment penetrations to support proper maintenance. No 
new accident precursors are created because the testing is conducted at 
a Pa value calculated to be representative of peak 
conditions throughout containment during a design basis accident. No 
new accident precursors are created by use of a Pa of 7.6 
psig instead of 9.3 psig, thus, the probability of postulated accidents 
is not increased. Therefore, there is no undue risk to public health 
and safety.

Consistent With Common Defense and Security

    The exemption would permit exclusion of the short duration spike in 
wetwell pressure as Pa for Appendix J testing purposes. This 
change to the interpretation of Pa as defined in Appendix J 
has no relation to security issues. Therefore, the common defense and 
security is not impacted by this exemption.

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 Entergy Operations, Inc., an 
exemption from the definition for Pa in 10 CFR part 50, 
appendix J for River Bend Station, Unit 1 and alternatively to continue 
to use a Pa value of 7.6 psig.
    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 (78 FR 50454; August 19, 2013).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 20th day of August 2013.

    For the Nuclear Regulatory Commission.
Michele G. Evans,
Director, Division of Operating Reactor Licensing, Office of Nuclear 
Reactor Regulation.
[FR Doc. 2013-21103 Filed 8-28-13; 8:45 am]
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