[Federal Register Volume 59, Number 84 (Tuesday, May 3, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-10530]
[[Page Unknown]]
[Federal Register: May 3, 1994]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-341]
Detroit Edison Co. (Fermi 2); Exemption
I
Detroit Edison Company (the licensee) is the holder of Facility
Operating License No. NPF-43 which authorizes operation of the Fermi 2
Nuclear Plant at steady-state reactor power levels not in excess of
3430 megawatts thermal. The Fermi 2 facility is a boiling water reactor
located at the licensee's site in Monroe County, Michigan. The license
provides, among other things, that it is subject to all rules,
regulations, and Orders of the Nuclear Regulatory Commission (the
Commission) now or hereafter in effect.
II
Paragraph III.C of appendix J to 10 CFR part 50 requires, in part,
that valves, unless pressurized with fluid (e.g., water, nitrogen) from
a seal system, shall be tested by pressurizing with air or nitrogen at
a test pressure of Pa (56.5 psig), the calculated peak containment
internal pressure as a result of the design basis accident. Further,
the combined leakage rate of all penetrations and valves subject to
Type B and C testing shall be less than 0.60 La (La is the maximum
allowable leakage rate at Pa). Leakage from containment isolation
valves that are sealed with fluid from a seal system may be excluded,
provided the leakage rates for these valves do not exceed the Technical
Specification leakage requirements and the seal system fluid inventory
is sufficient to ensure the sealing function for 30 days following an
accident at a pressure of 1.10 Pa.
Pursuant to 10 CFR 50.12(a), the NRC may grant exemptions from the
requirements of the regulations (1) which are authorized by law, will
not present an undue risk to the public health and safety, and are
consistent with the common defense and security; and (2) where special
circumstances are present.
III
By letter dated May 24, 1993, the licensee requested an exemption
from the requirements of 10 CFR part 50, appendix J, III.C for
performing Type C integrated leak rate tests of the containment
isolation valves in the Low pressure coolant injection (LPCI) lines of
the residual heat removal (RHR) system. The valves in question are the
loop A and B LPCI isolation valves, which are motor-operated gate
valves, outboard of containment and which are operable from the control
room and are designated as E11-F015 A and B. The licensee proposed, as
alternative testing, an external leakage test, with water as the test
medium, at a pressure of 1045 psig with an allowable leakage value of 5
milliliters per minute (ml/min). The license also provided
justification in its May 24, 1993, letter to reclassify the inboard
containment LPCI valve configuration (which consists of a reverse flow
swing check valve with a 1-inch, locked closed, solenoid-operated
bypass valve) as other than containment isolation valves and thus no
longer subject to Type C testing.
The staff evaluated the licensee's proposal for reclassification of
the inboard containment valves and concluded that the licensee's
proposal met the guidance in the Standard Review Plan (SRP), NUREG-
0800, Section 6.2.4 for differing from the explicit requirements of
General Design Criterion 55 in 10 CFR part 50, appendix A for
containment isolation valves (CIVs). Subsection II.6.e allows only a
single CIV outside containment, if the system is closed outside
containment and certain other criteria are met. Details concerning the
staff's review are contained in the staff's safety evaluation dated
April 22, 1994.
Two aspects of the RHR system form the basis for the proposed
exemption. It is a closed system outside of containment, and the
containment penetrations will be water sealed during a loss of coolant
accident (LOCA). The licensee's analyses showed that a water seal.
pressurized to greater than 1.1 Pa (62.15 psig), would exist outboard
of the LPCI CIV for at least 30 days following the design basis LOCA
despite the most limiting single active failure. However, if one or
both of the LPCI CIVs is shut, that water seal might not prevent
external valve leakage (valve stem or bonnet leakage). The licensee
also showed that a water seal, would exist inboard of the LPCI CIVs
following a design basis LOCA. The licensee's analyses demonstrated
that the volume of the water seal is sufficient to last for greater
than 30 days assuming the leakage limit proposed in their alternative
testing acceptance criteria. The licensee's analyses also showed that
through seat leakage of the LPCI CIVs would be in toward containment
and would not deplete the water seal.
Although the external leakage water seal would prevent atmosphere
from leading out of containment, it does not satisfy the requirements
for a water seal contained in Appendix J. Appendix J allows water
sealed valves to be excepted from the normal Type C testing with air,
but it requires that the water seal be pressurized to at least 1.1 Pa
during an accident. The water leg inboard of the LPCI CIVs does not
meet this requirement. Nevertheless, the staff has determined that the
licensee's analyses of the water seals provide sufficient assurance
that containment atmosphere leakage out of containment will be
prevented during an accident to justify granting the requested
exemption from Type C testing of the LPCI CIVs with air as the test
medium. The licensee's alternative test will measure external valve
leakage with a limit of 5 ml/min using water as the test medium at a
pressure of 1045 psig.
IV
Accordingly, the Commission concluded that the licensee's proposed
alternative testing plan and analyses provide sufficient assurance that
the containment atmosphere would not leak out of containment through
the LPCI CIVs during a design basis accident and that containment
integrity will be maintained by granting the proposed exemption.
The special circumstances for granting this exemption pursuant to
10 CFR 50.12 have also been identified. As stated in part in 10 CFR
50.12(a)(2)(ii), special circumstances are present when application of
the regulation in the particular circumstances is not necessary to
achieve the underlying purpose of the rule. The purpose of Section
III.C of Appendix J is to measure containment isolation valve leakage
rates. This leakage, when summed with the allowable Type A and Type B
leakage is limited to a value which ensures overall containment
integrity in preventing the uncontrolled release of radioactivity to
the environment. The licensee has demonstrated through analyses and by
proposing alternative testing criteria, that containment integrity will
be maintained. Consequently, the Commission concludes that the special
circumstances of 10 CFR 50.12 (a)(2)(ii) exist in that application of
the regulation in these particular circumstances is not necessary to
achieve the underlying purpose of the rule.
V
Accordingly, the Commission has determined that, pursuant to CFR
50.12 this exemption as described in Section III above 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. The Commission
further determines that special circumstances as provided in 10 CFR
50.12(a)(2)(ii) are present justifying the exemption.
Therefore, the Commission hereby grants an exemption as described
in Section III above the requirements in 10 CFR 50.12, Appendix J,
III.C. for performing Type C containment integrated leak rate tests of
the CIVs in the LPCI lines of the RHR system and approves the
licensee's alternative testing plan.
Pursuant to CFR 51.32, the Commission has determined that the
granting of this exemption will have no significant impact on the
environment (59 FR 19028).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 22nd day of April 1994.
For the Nuclear Regulatory Commission.
Elinor G. Adensam,
Acting Director; Division of Reactor Projects--III/IV; Office of
Nuclear Reactor Regulation.
[FR Doc. 94-10530 Filed 5-2-94; 8:45 am]
BILLING CODE 7590-01-M
