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Nebraska Public Power District, Cooper Nuclear Station;

 

Nebraska Public Power District, Cooper Nuclear Station; 



[Federal Register: November 14, 1995 (Volume 60, Number 219)]
[Notices]               

[Page 57250-57252]

>From the Federal Register Online via GPO Access [wais.access.gpo.gov]









NUCLEAR REGULATORY COMMISSION



[Docket No. 50-298]

 


Nebraska Public Power District, Cooper Nuclear Station; 
Environmental Assessment and Finding of No Significant Impact



    The U.S. Nuclear Regulatory Commission (the Commission) is 
considering the issuance of an exemption from certain requirements of 
its regulations to Facility Operating License Number DPR-46. This 
license was issued to the Nebraska Public Power District (the licensee) 
for operation of the Cooper Nuclear Station (CNS) located in Nemaha 
County, Nebraska.



Environmental Assessment



Identification of the Proposed Action



    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 WaterCooled 
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 P<INF>a, (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, P<INF>a 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. 



[[Page 57251]]




The Need for the Proposed Action



    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 P<INF>a.

    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 P<INF>a and, as 
relevant here, 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 P<INF>a, or the test pressure specified in the TSs, which for CNS is 
stipulated 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 
P<INF>a. If this second test is not necessary to satisfy the 6-month 
interval test requirement, there is no requirement that the licensee 
conduct it at P<INF>a.

    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 P<INF>a has been performed successfully, opening of the air lock 
during a plant shutdown or refueling outage is not a reason to expect 
it to leak in excess of the requirements. When the air lock is tested 
at a pressure less than P<INF>a in preparation for restart from 
refueling or cold shutdown, under such conditions, and the air lock has 
been successfully tested at P<INF>a within the previous six months, 
containment integrity is assured. If, however, 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 P<INF>a.
    In testing the air lock at reduced pressure, 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 
P<INF>a 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 P<INF>a is sufficiently high to damage the inner door 
during the test without the strongback. The reduced pressure test would 
be conducted at 3 psig, and the strongback would not be needed to 
protect the inner door during the test.
    Installing a strongback, performing the test, and removing the 
strongback requires several hours during which access through the air 
lock is prohibited. The strongback is attached to the door inside 
containment where personnel would be exposed to radiation inside 
containment. The reduced pressure test could be conducted without the 
strongback and, thus, in a shorter time with less occupational exposure 
to CNS personnel involved with the test. Because the second test is 
conducted at P<INF>a, not performing the first test at P<INF>a will 
reduce the number of such tests using strongbacks and, therefore, will 
reduce the time involved in performing the tests and the magnitude of 
occupational exposure at CNS.

    The licensee is, therefore, proposing to conduct the first test 
during restart at a test pressure of 3 psig, which is less than 
P<INF>a, which is not presently allowed by Section III.D.2(b)(ii). The 
air lock leakage measured for the reduced test pressure would be 
extrapolated to a value consistent with P<INF>a, 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.



Environmental Impacts of the Proposed Action



    The Commission has completed its evaluation of the licensee's 
request. The proposed exemption does not change the number of air lock 
tests to verify containment integrity upon plant restart, the manner in 
which the second test is conducted, the time when the tests would be 
conducted, nor the acceptance criteria for the tests. Thus, the 
assurance of containment integrity would be maintained at a level 
consistent with current Appendix J requirements. The proposed exemption 
would also not change other requirements in Appendix J for periodic 
testing of the air lock at P<INF>a, and would not change the existing 
CNS safety limits, safety settings, power operations, or effluent 
limits. The proposed exemption would effectively replace the test 
pressure requirement in Section III.D.2(b)(ii) with that in Section 
III.D.2(b)(iii), in that the latter section allows for reduced pressure 
testing of air locks in accordance with plant TSs.
    The change will not increase the probability or consequences of 
accidents, no changes are being made in the types of any effluents that 
may be released offsite, and there is no significant increase in the 
allowable individual or cumulative occupational radiation exposure. 
Accordingly, the Commission concludes that there are no significant 
radiological environmental impacts associated with the proposed action.
    With regard to potential nonradiological impacts, the proposed 
action does involve features located entirely within the restricted 
area as defined in 10 CFR Part 20. It does not affect nonradiological 
plant effluents and has no other environmental impact. Accordingly, the 
Commission concludes that there are no significant nonradiological 
environmental impacts associated with the proposed action.



Alternatives to the Proposed Action



    Since the Commission has concluded that there is no measurable 
environmental impact associated with the proposed action, any 
alternatives with equal or greater environmental impact need not be 
evaluated. As an alternative to the proposed action, the staff 
considered denial of the requested 



[[Page 57252]]

exemption. Denial of the application would result in no change in 
current environmental impacts. The environmental impacts of the 
proposed action and the alternative action are similar, but the 
proposed action would reduce occupational exposure at CNS.



Alternative Use of Resources



    This action does not involve the use of any resources not 
previously considered in the Final Environmental Statement for the 
Cooper Nuclear Station, dated February 1973.



Agencies and Persons Consulted



    In accordance with its stated policy, on October 19, 1995, the 
staff consulted with the Nebraska State official, Ms. Julia Schmidt, 
Division of Radiological Health, Nebraska Department of Health, 
regarding the environmental impact of the proposed action. The State 
official had no comments.

Finding of No Significant Impact

    Based upon the environmental assessment, the Commission concludes 
that the proposed action will not have a significant effect on the 
quality of the human environment. Accordingly, the Commission has 
determined not to prepare an environmental impact statement for the 
proposed action.

    For further details with respect to this action, see the licensee's 
request for an 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 local public 
document room located at the Auburn Public Library, 118 15th Street, 
Auburn, Nebraska 68305.



    Dated at Rockville, Maryland, this 6th day of November 1995.



    For the Nuclear Regulatory Commission.
James R. Hall,

Senior Project Manager, Project Directorate IV-1, Division of Reactor 
Projects III/IV, Office of Nuclear Reactor Regulation.
[FR Doc. 95-28028 Filed 11-13-95; 8:45 am]
BILLING CODE 7590-01-P

 
 

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