[Federal Register Volume 60, Number 235 (Thursday, December 7, 1995)]
[Notices]
[Pages 62893-62895]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-29812]



=======================================================================
-----------------------------------------------------------------------

NUCLEAR REGULATORY COMMISSION

[Docket No. 50-298]


Exemption

    In the Matter of: Nebraska Public Power District (Cooper Nuclear 
Station).

I.

    Nebraska Public Power District (the licensee) is the holder of 
Facility Operating License No. DPR-46, which authorizes operation of 
the Cooper Nuclear Station (CNS) at power levels not in excess of 2381 
megawatts thermal. The facility consists of a boiling water reactor at 
the licensee's site in Nemaha County, Nebraska. The operating license 
provides, among other things, that CNS is subject to all rules, 
regulations, and orders of the Commission now or hereafter in effect.

II.

    The licensee requested, in its application dated May 13, 1994, an 
exemption from the pressure test requirements of Section III.D.2(b)(ii) 
of Appendix J, ``Primary Reactor Containment Leakage Testing For Water-
Cooled Power Reactors,'' to 10 CFR Part 50 (Appendix J to 10 CFR Part 
50). The staff discussed the details of the proposed exemption with the 
licensee in a telephone conference call on September 28, 1995. The 
proposed exemption would allow the licensee to leak test the personnel 
air lock at CNS at a test pressure less than Pa, (the calculated 
peak containment internal pressure resulting from the containment 
design basis accident), under certain conditions. The reduced pressure 
test of the air lock would be conducted as the first of two tests 
during a restart from refueling or cold shutdown, prior to entry into 
an operational mode requiring containment leaktight integrity by the 
CNS Technical Specifications (TSs). As stated in CNS TS 4.7.A.2.f.5, 
for periodic leakage testing of the personnel air lock, Pa is 58 
psig and the reduced test pressure is 3 psig.
    This leakage test is part of the Type B tests required by Appendix 
J to 10 CFR Part 50 to verify containment integrity. Because an air 
lock allows entry into the containment and is part of the containment 
pressure boundary, excessive leakage through the air lock could 
compromise containment integrity. The air lock consists of an inner and 
outer door and the leakage test is performed by pressurizing the space 
between the doors.
    Section III.D.2 of Appendix J to 10 CFR Part 50 specifies the 
required periodic retest schedule for Type B tests, including testing 
of air locks. Pursuant to Section III.D.2(b)(ii), licensees are 
required to leakage test air locks, opened during periods when 
containment integrity is not required by the TSs, at the end of such 
periods. This section applies to testing of air locks during restart 
from refueling or cold shutdown because the CNS TSs do not require 
containment integrity for either of these operational modes. This 
section states that the air lock test shall be performed at a pressure 
that is not less than Pa.
    The proposed exemption is concerned with Section III.D.2(b)(ii); 
however, there are two other sections in Appendix J which have 
requirements on testing air locks. Section III.D.2(b)(i) requires an 
air lock test every 6 months at a test pressure of Pa and Section 
III.D.2(b)(iii) requires a test every 3 days when the air lock is used 
during a period when containment integrity is required by the TSs. The 
latter section requires the test pressure to be Pa, or the test 
pressure specified in the TSs, which for CNS is specified as 3 psig in 
TS 4.7.A.2.f.5.
    The licensee stated in its application that it currently tests the 
personnel air lock twice during the restart of the plant for power 
operation from refueling or cold shutdown: (1) Prior to the reactor 
being taken critical, or the reactor water temperature being above 
100 deg.C (212 deg.F), and (2) after the last entry into containment 
for leak inspection during restart. The time between the two tests is 
about 24 to 48 hours, and the second test is at low reactor power prior 
to entry into the run mode, the full power mode of operation.
    The first test is in accordance with Section III.D.2(b)(ii) and is 
performed at the conclusion of the period when containment integrity is 
not required by the TSs. This test is conducted prior to entry into an 
operational mode requiring containment integrity. The second test is in 
accordance with Section III.D.2(b)(iii) and is performed at 3-day 
intervals while the air lock is being used when containment integrity 
is required. As stated above, in accordance with this section, the 
second test could be conducted at a test pressure of 3 psig at CNS, 
because this pressure is stated in TS 4.7.A.2.f.5. However, because the 
licensee also performs the second test to meet the 6-month interval 
requirement in Section III.D.2(b)(i), the second test is conducted at 
Pa.
    The proposed exemption would not change the number of air lock 
tests for the restart to power operation for CNS, the manner in which 
the second test is 

[[Page 62894]]
conducted, the time when the tests would be run, nor the acceptance 
criteria for the tests. The proposed exemption also would not change 
the requirements of Section III.D.2(b)(i) regarding the 6-month 
periodic test of the air lock at Pa, nor the existing CNS safety 
limits, safety settings, power operations, or effluent limits.

III.

    Pursuant to 10 CFR 50.12(a), ``Specific exemptions,'' the 
Commission may, upon application of any interested person or upon its 
own initiative, grant such exemptions in this part as it determines 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 
for which special circumstances identified in 50.12(a)(2) are present.
    The licensee is proposing to conduct the first air lock test during 
restart at a test pressure of 3 psig, which is less than Pa, which 
is not presently allowed by Section III.D.2(b)(ii). The air lock 
leakage measured at the reduced test pressure would be extrapolated to 
a value consistent with Pa, then that value would be compared to 
the acceptance criteria in Appendix J for Type B tests to confirm that 
containment integrity is verified. If containment integrity is 
verified, the measured air lock leakage is considered acceptable.
    For CNS, by testing the air lock at reduced pressure of 3 psig, a 
strongback (structural bracing) would not have to be installed on the 
inner air lock door. During the test, the space between the inner and 
outer doors is pressurized. The strongback is needed when the test 
pressure is Pa because the pressure exerted on the inner door 
during the test is in a direction opposite to the pressure on the inner 
door during an accident, and the test pressure is sufficiently high to 
damage the inner door without the strongback. The reduced pressure test 
is conducted at a pressure low enough such that the strongback is not 
needed to protect the inner door.
    When no maintenance or repairs have been performed on the air lock 
that could affect its sealing capability and the periodic 6-month test 
at Pa has been performed successfully, there is no reason to 
expect the air lock to leak excessively because it has been opened 
during a plant shutdown or refueling outage. When the air lock is 
tested at a pressure less than Pa in preparation for restart from 
refueling or cold shutdown, the air lock would have been successfully 
tested at Pa within the previous six months.
    Accordingly, the Commission concludes that the licensee's proposed 
exemption to conduct the first air lock test during the restart from 
refueling or cold shutdown (when the air lock was opened while 
containment integrity was not required by the TSs) at the reduced 
pressure of 3 psig in CNS TS 4.7.A.2.f.5 is acceptable, provided no 
maintenance or repairs have been performed on the air lock which would 
affect its sealing capability since the last 6-month test required by 
Section III.D.2(b)(i) of Appendix J. Section III.D.2(b)(i) requires a 
test of the air lock at not less than Pa every 6 months since the 
initial fuel loading and this requirement is not being changed by this 
exemption. If maintenance or repairs have been performed on the air 
lock affecting its sealing capability since the last 6-month test, the 
first test prior to entering a condition which requires containment 
integrity must meet the test pressure requirements of Section 
III.D.2(b)(ii) and be conducted at a test pressure not less than 
Pa.
    Although the licensee conducts the second air lock test during 
restart at Pa to meet Section III.D.2(b)(i) and thus begin the 6-
month interval for air lock tests during the power operating cycle, 
this exemption does not require that the second test be conducted at 
Pa. The entry into an operational mode which requires containment 
integrity by the TSs must be based on an assurance that the containment 
has such integrity. This assurance can not rely on a test to be 
conducted hours or days in the future after the operational mode has 
been entered, unless the proper test can only be conducted after 
entering the operational mode (i.e., the proper conditions for the test 
do not exist in the prior mode). An air lock test at Pa could be 
conducted before entering the operational mode requiring containment 
integrity and has been conducted in this manner in the past at CNS. 
Therefore, in approving this exemption to allow the first air lock test 
during restart to be conducted at the reduced test pressure of 3 psig, 
the staff does not rely on the second test being conducted at Pa. 
The method used to correlate the reduced pressure leakage rates to the 
full pressure leakage rates shall be in accordance with the NRC staff's 
safety evaluation and the Franklin Research Center technical evaluation 
report enclosed with the exemption of September 3, 1982.
    The special circumstances for granting this exemption pursuant to 
10 CFR 50.12 have been identified in the licensee's application dated 
May 13, 1994. The purpose of Appendix J to 10 CFR Part 50 is to ensure 
that the containment leaktight integrity can be verified periodically 
throughout the service lifetime of the containment (including the air 
lock) so as to maintain containment leakage within the limits specified 
in the design basis accident analyses that were part of the basis for 
licensing CNS. The proposed alternative test method is sufficient to 
achieve the underlying purpose of the regulation in that it provides 
adequate assurance of the leaktight integrity of the air lock, and thus 
of the containment.
    Consequently, the special circumstances described in 10 CFR 
50.12(a)(2)(ii) exist in that the application of the regulation in 
these particular circumstances is not necessary to achieve the 
underlying purpose of the rule in that the licensee has proposed an 
acceptable alternative test method that accomplishes the intent of the 
regulation.

IV.

    Based on the findings and conclusions above, the Commission has 
determined that, pursuant to 10 CFR 50.12(a), the exemption requested 
by the licensee in its letter dated May 13, 1994, is authorized by law, 
will not present an undue risk to the public health and safety, is 
consistent with the common defense and security, and has present 
special circumstances which are identified in 50.12(a)(2). The 
Commission hereby grants to the licensee an exemption from the 
requirements in Section III.D.2(b)(ii) of Appendix J to 10 CFR Part 50, 
to allow reduced pressure testing of the personnel airlock in 
accordance with TS 4.7.A.2.f.5, prior to entry into operational modes 
requiring containment integrity, provided there has been no maintenance 
or repair of the air lock that could affect its sealing capability 
since the last 6-month test of the air lock.
    Pursuant to 10 CFR 51.32, the Commission has also determined that 
the issuance of the exemption will have no significant impact on the 
environment. An Environmental Assessment and Finding of No Significant 
Impact was noticed in the Federal Register on November 6, 1995 (60 FR 
57250).
    For further details with respect to this action, see the licensee's 
request for exemption dated May 13, 1994, which is available for public 
inspection at the Commission's Public Document Room, the Gelman 
Building, 2120 L Street, NW., Washington, DC, and at the Commission's 
Local Public Document Room at the Auburn Public Library, 118 15th 
Street, Auburn, NE 68305.
    This exemption is effective upon issuance.


[[Page 62895]]

    Dated at Rockville, Maryland this 30th day of November 1995.

    For the Nuclear Regulatory Commission.
Jack W. Roe,
Director Division of Reactor Projects III/IV, Office of Nuclear Reactor 
Regulation.
[FR Doc. 95-29812 Filed 12-6-95; 8:45 am]
BILLING CODE 7590-01-P