ML19339A534
| ML19339A534 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/27/1980 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19339A535 | List: |
| References | |
| IEB-80-12, TAC-42126, NUDOCS 8011040208 | |
| Download: ML19339A534 (3) | |
Text
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SACRAMENTO ' MUNICIPAL UTILITY DISTRICT O 6201 S Street, Box 15830, Sacrarnento, California 95813; (916) 452 3211 October 27, 1980 Mr. Darrell G. Eisenhut,' Director Division of Licensing Office of Nuclear Reactor Regulation Nuclear Regulatory Commission Washington, D.C.
20555 Re: Docket.No. 50-312 Proposed Amendment No. 74 Rancho Seco Nuclear Generating Station, Unit No. 1
Dear Mr. Eisenhot:
In accordance with 10 CFR 50.59, the Sacramento Municipal Utility District proposes to amend its operating license, DPR-54, for Rancho Seco Nuclear Generating Station No. I, by submitting Proposed Amendment No. 74 on October 28, 1980. Today, we are submit-ting forty (40) copies of Proposed Amsndment No. 74 which shows the changes we are proposing. Under this cover, we will be providing payment for this submittal, as required per 10 CFR 170, and letter dated June 11, 1980. This amendment has been determined to be Class ill since the issues have been clearly identified by NRC position.
A payment of $4,000 is enclosed.
The letter transmitted a request to amend our Technical Specifications for our facility with respect to reactor decay heat removal capability.
The basis for your request was founded in a number of events that have occurred at operating PWR facilities where decay heat removal capability has been seriously degraded due to it: adequate administrative controls utilized during shutdowns.
The District had assessed the problem in response to IE Bulletin 80-12 dated tiay 9, 1980. The response described two distinct differences between the Davis-Beese and Rancho Seco DHR/ECCS systems that preclude the probability of a similar occurrence at Rancho Seco. These differences are:
a.
At Rancho Seco, the DHR system suction valves from the RCS (HV-20001 and 20002) are not automatically closed for containment isolation on an ECCS signal.
b.
At Randho Seco, the Reactor Building Emergency Sump isolation valves are not automatically opened on an
-ECCS signal.
However, minor interruptions of' decay heat flow can occur at Rancho Seco. The most probable cause would be the tripping or loss of a 120V vital power inverter. This would result in the RCS d
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Darrell G. Eisenhut October 27, 1980 pressure transmitters (PT-21092 and 21099) indicating a high RCS pressure and causing the interlocked DHR suction valves (s) (HV-20001 and 20002) to close. A second Interlock between the valve (s) and the pump (s) would then trip the operating DHR pump (s).
In the esent of such an incident, DHR flow can be reestablished by either restoring 120V vital power or dispatching an operator to manually open the DHR suction valve. Such an event would not allow air to enter the system and therefore, time-consuming venting of the system prior to reestablishing flow would not be necessary.
'Duri.ng the recent refueling outage a situation arose where the OHR system redundancy was degraded. This situation was initiated by mechanical failure of the "A" DHR pump seal. This was reported to your office via LER 80-5 Recognizing the aspects of degraded redundancy, an analysis of plant procedures for diversity of DHR capability and adequacy of responding to OHR-loss events ensued. This resulted in a special order to all operating personnel (50 1-80 dated January 28, 1980),
giving specific instructions on providing alternate core cooling in the evert of a loss of both DHR systems. These detailed instructions were later incorporated into Emergency Procedure D.16, Loss of Decay Heat Removal System, on March 17, 1980.
Accordant with your request, Proposed Amendment No. 74 contains additional limitations pertaining to decay heat operability during shutdown.
Clarifications and explanations of.your request include:
1)
S.T.S. Section 3/4.4.1 does not apply to Rancho Seco because the Reactor's Protection system trips automatically with one reactor coolant pump operational and cannot be bypassed during start-up or power operation. The setpoints for less than four-pump operation (i.e. nuclear overpower based on RCS flow and axial power imbalance and nuclear overpower based on pump, monitors) are reduced automatically.
Nuclear overpower flux monitors need not be reduced because the other moniters will provide sufficient reactor protection.
The requirements are summarized in Table 2.3-1 of our Technical Specifications.
2) 5.T.S. Section 3.4.1.2 is al ready a requirenent in the Rancho Seco Technical Specifications. The decay heat removal at hot standby requirements are specified in Section 3.1.1.2A and 3.4 of the Rancho Seco Technical Specifications.
The reactor coolant pump limits as referenced in the S.T.S. action of Section 3.4.1.2 is stated in Rancho Seco Technical Specification Section 3.1.1.1.B.
3)
S.T.S. Section 3.4.1.3a has been added to Rancho Seco Technical Specifications Section 3.1.1.4.
S.T.S. Section 3.4.3b is already a requirement during cold shutdown as stated in Rancho Seco Technical Specifications Section 3.1.1.1.B.
4)
S.T.S. Sections 3 9.8.1 and 3.9.8.2 ve been added to Rancho Seco Technical Specifications Section 3.8.3 and associated bases.
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Darrell G. Eisenhut October 27, 1980 Mr. R. Colombo, on my staff at Rancho Seco, will clarify and answer any questions concerning this proposal.
Sincerely, ft.a.,
R J. J. Mattimoc Assistant General Manager and Chief Engineer JJM:RWC:rm i
Sworn to me and subscribed before me suunnameuan:nx:::nmwaminrwemw.-
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- MARY ALICE DAY this _.7Br# day of October,1980.
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