[Federal Register Volume 60, Number 219 (Tuesday, November 14, 1995)]
[Notices]
[Pages 57250-57252]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-28028]
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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 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.
[[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 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, 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 Pa, 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
Pa. 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 Pa.
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, 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 Pa in preparation for restart from
refueling or cold shutdown, under such conditions, and the air lock has
been successfully tested at Pa 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 Pa.
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
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 Pa 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 Pa, not performing the first test at Pa 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
Pa, 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 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.
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 Pa, 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
