[Federal Register Volume 78, Number 168 (Thursday, August 29, 2013)]
[Notices]
[Pages 53482-53483]
From the Federal Register Online via the Government Publishing 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, http://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]
BILLING CODE 7590-01-P