ML20204G373
| ML20204G373 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 07/31/1986 |
| From: | Lainas G Office of Nuclear Reactor Regulation |
| To: | DETROIT EDISON CO. |
| Shared Package | |
| ML20204G171 | List: |
| References | |
| NUDOCS 8608070237 | |
| Download: ML20204G373 (6) | |
Text
7590-01 i
UNITED STATES OF AMERICA NUCLEAR PEGULATORY COMMISSION In the Matter of
)
DETROIT EDISON COMPANY
)
WOLVERINE POWER SUPPLY COOPERATIVE,
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Docket No. 50-341 INCORPORATED
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(Fermi-2)
)
EXEMPTION I.
Detroit Edison Company (DECO or the licensee) is the holder of Facility Operating License No. NPF-43 which authorizes the operation of the Fermi-2 facility at steady-state power levels not in excess of 329? megawatts thermal.
The license provides, among other things, that the facility is subject to all rules, regulations and Orders of the Nuclear Pegulator.v Comission (the Commission) now or hereafter in effect.
The facility is a boiling water reactor (BWR) located at the licensee's site in Monroe County, Michigan.
II.
The NRC staff identified a concern with the design features of the 3/8-inch nitrogen purge line associated with the traversing in-core probe (TIP) system, in a letter dated November 21, 1985. The then current des'ign of this line, identified as penetration X-35G in Table 6.2-2 of the Fermi-2 FSAR, was based on the classification of this penetration of primary containment by the licensee as an instrument line. This classification, if accepted by the NPC staff, would permit the licensee to install only a single check valve outside containment consistent with the guidelines in Section C.2.a of Regulatory Guide 1.11. That was the valving configuration for the subject penetration at that time.
l The NRC staff disagreed with the licensee's classification for the subject I
containment penetration on the basis that while this line was indeed a portion 8608070237 860731 PDR ADOCK 05000341 P
PDR i
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2 of an instrument system, the line itself did not in any manner provide any func-tinn that remotely corresponds to the function of an instrument line.
In point of fact, the only purpose for this line is to remove any oxygen from the TIP system inside containment by purging this system with nitrogen.
Thereafter, this line must be secured in such a fashion to maintain the nitrogen atmosphere in that portion of the TIP system inside containment.
In the event of any condition which would generate an isolation signal, this line must isolate and remain closed until such time as the isolation signal is cleared.
Considering both the function and the operational requirements of this con-tainment penetration, the NRC staff concluded that this line cannot be classified as an instrument line.
(An instrument line might be expected to be operable in the event of an accident so as to follow tne course of the accident; this is clearly not the intended function of penetration X-35G.) Accordingly, it is the staff's position that this penetration must comply with the provisions of General Desion Criteria (GDC) 55 and 56 reoarding the installation of isolation valves.
In resoonse to the NPC staff position on this matter, the licensee committed in its letter dated December 31, 1985, to revise the design features of penetra-tion X-35G to comply with GDC 56.
(The requirements for isolation valves in GDC 55 are identical to those in GDC 56.) Specifically, the licensee committed to install a check valve inside containment and an automatic isolation valve outside containment. The automatic isolation valve will receive diverse isolation signals.
While the NRC staff finds that the proposed modification described above complies with the criteria in GDC 56 to install one valve inside and one valve outside containment, our evaluation of the acceptability of the proposed long-term
o
. o modification cannot be completed until we receive additional information from the licensee regarding placement of the outboard isolation valve and the types of isolation sionals which will actuate the automatic valve.
Because of the scope of this modification, the lead time to design this installation and the subsequent procurement of components, the licensee states, in its letter of December 31, 1985, that it cannot implement its commitment, cited above, until the first scheduled refueling outage without sionificantly delayino restart of the facility.
(Restart of the Fermi-2 facility is presently estimated by the licensee to occur in late July 1986.) For this reason, the licensee proposed in its letter of December 31, 1985, to install an interim modification to the sub,iect containment penetration which will provide a signifi-cantly increased containment isolation capability over that of the prior design.
This interim modification consists of two dutomatic ball valves outside primary containment. The valves and their installation will be in compliance with the cuality assurance criteria for safety-related components and will isolate automatically on receipt of either of two diverse containment isolation signals; i.e., a sianal indicating that: (a) the reactor vessel water level has fallen below level 3; or (b) there is a high drywell pressure. lipon loss of power, these two ball valves will be closed by springs.
Because the proposed interim modification is not in full compliance with all the provisions of GDC 56, the licensee has requested an exemption from GDC 56 in accordance with 10 CFR 50.12 until it is able to come into full compliance with GDC 56 at the first scheduled refueling outage.
III.
The two automatic ball valves proposed by the licensee for an interim modifi-cation of penetration X-35G meet nearly all the applicable NRC staff requirements
-4.
for components servino as part of the reactor vessel pressure boundary. Namely, they will be: (1) designed, manufactured and installed to the appropriate quality assurance standards; (?) actuated by diverse signals; (3) closed by sprinas on loss of power which is in compliance with the requirements of GDC 56; (4) designed and installed to seismic Category I criteria; and (5) leak tested per Appendix J to 10 CFR Part 50. The proposed interim modification differs from the reouirements of GDC 56 only in that it does not include one valve inside containment. We find, however, that the proposed interim modification provides a containment isolation capability comparable to that reau1 red by GDC 56.
On the basis that the proposed interim modification of primary containment penetration X-35G will be for a limited time period and provides containment isolation capability comparable to that required by GDC 56, we find that the proposed exemption fron GDC 56 poses no increase in risk to public health and safety. On this basis, we find that the proposed interim exemption from the requirement in GDC 56 of Appendix A to 10 CFP Part 50 to have one isolation valve inside and one isolation valve outside, is acceptable.
IV.
Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12, this 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. The Commission further determines that special circumstances, as provided in 10 CFR 50.12(a)(2)(v), are present justifying the exemption, namely that the exemption would provide only temporary relief from the applicable regulation and the licensee has made good faith efforts to comply with the regulation. The good 1
faith effort by the licensee is demonstrated by its relatively prompt response
- to the NRC staff's position on this matter. The staff informed the licensee of its position in a letter dated November 11, 1985; the licensee acknowledged the staff's position on December 2, 1985, provided a commitment to comply with the provisions of GDC 56 in its letter dated December 20, 1985, and submitted its proposal for an interim and long-term resolution of this matter on December 31, 1985. As discussed in Section III, the licensee has indicated in its letter of December 31, 1985, that the time required to design, precure and install the lono-term modification prevents it from implementing its comitment prior to the first refueling outaoe. Based on this prompt response and the licensee's commit-ment to implement the long-term resolution at the earliest practical opportunity (i.e., the first scheduled refueline outage), the Commission concludes that the licensee has made a aood faith effort to come into compliance with the require-ments of GDC 56. Therefore, the Commission hereby approves the following exemption:
With respect to the requirement in General Design Criterion 56 to provide each line that connects directly to the containment atmosphere and penetrates primary reactor containment, with two containment isola-tion valves, one inside and one outside containment, exemption is granted from this requirement for penetration X-35G for a limited period not extending beyond the first scheduled refueling outage.
The Comnission has further determined that the exemption does not authorize a change in effluent types or total amounts of effluents nor an increase in power level and will not result in any significant environmental impact.
In light of this determination, and as reflected in the Notice of Environmental Assessment and Finding of No Significant Impact prepared pursuant to 10 CFR 51.21 and 51.30
6-through 51.3?, it is concluded that the instant action is insianificant from the standpoint of environmental impact and an environmental impact statement need not be orepared.
For further details with respect to this action, see the licensee's request dated December 31, 1985, which is available for public inspection at the Commission's Public Document Room,1717 H Street, N.W., Washington, D. C.
20555 and at the Monroe County Library System, 3700 South Custer Poad, Monroe, Michigan 48161.
Pursuant to 10 CFP 51.32, the Commission has determined that the granting of this Exemption will have not significant impact on the environment (51 FR 76959 dated July 28, 1986).
This exemption is effective upon issuance.
FOR THE NilCLEAR REGULATORY COMMISSION sdisa-Gus Lainas, Acting Director Division of BWR Licensino Office of Nuclear Reactor Regulatior 1
Dated at Bethesda, Maryland y
this 31st day of July 1986 3
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