ML20245G037

Safety Evaluation Supporting Amend 131 to License NPF-3

ML20245G037
Person / Time
Site:	Davis Besse
Issue date:	04/25/1989
From:	Office of Nuclear Reactor Regulation
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Shared Package
ML20245G021	List: ML20245G017 ML20245G037 ML20245G165
References
NUDOCS 8905030056
Download: ML20245G037 (4)

Text

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f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 131 TO FACILITY OPERATING LICENSE NO. NPF-3

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TOLEDO EDIS0N COMPANY AND TE CLEVELAND ELECTRIC ILLUMINATpG COMPANY DAVIS-BESSE HUCLEAR POKER STATION, UNIT NO. 1 DOCKET N0. 50-346 t'

I.0 INTRODUCTION The licensee for Davis-Bt.sse Nuclear Power Station, Unit 1 (Toledo Edison Company) submitted an application for an amendment to the operating licensc

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dated May 4,1987 as su aplemented by submittal dated April 29, 1980. The application requested t1at the Technical Specifications be revised to relocate the specifications relativg to the Auxiliary Feed Pump lurbine (AFPT) inlet steam pressure interlocks by deleting a part of Surveillance Requirement x

4.7.1.2.d which specifies that the AFPT inlet steam pressure interlocks are to be demonstrated operable as part of the Aux 111r.ry Feedwater System, by performance of a channel functional test at least once per 31 days, and a channel calibration at least once per 18 months.

In addition, the licensee proposed to add the requirement for operable pressure interlocks as a separate specification action statement and a separate surveillance specification requirement. The appropriate statement was addeo to the Basis section of the Technical Specifications.

s 2.0,0ISCUSSION The present Davis-Besse Auxiliary Feedwater (AFW) system is shown in Figure 1, attached. Prior to the June 9, 1985 loss-of-feedwater event, valves MS-106, MS-106A, MS-107 and MS-107A, on the steam admittance lines to the AFW pump turbines, were retained in closed position. Thus, the portion of the steam i

admittance lines downstream of these valves remained at ambient pressure.

Pressur' switches PSL 106A through 106D were interlocked with motor operated steam JJmission valves MS 106 and MS106A while PSB 107A through 107D were i

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- interlocked with steam admission valves MS 107 and MS 107A.

These switches are designed to initiate closure of these four steam admission valves (or to maintain closure if already closed) in the event they detect low pressure. As initially designed, the steam admission valves wen. closed, and opened in response to a steam and feedwater rupture control system (SFRCS) signal. The pressure switches, originally in the tripped position because of sensing ambient pressure moved into the untripped position as a result of the pressure i

of the steam being admitted. Thereafter, a break in a steam admittance line which results in a lower pressure would cause the pressure switches to move into the tripped position, initiating closure of the steam admittance valves in the broken line.

It should be noted that the two air-operated valves, MS 5889 A and B shown on Figure 1 downstream of the pressure switch interlocks, were not part of that-l original design; they were introduced as part of the new design after the 1

June 9,1985 LOFW event and supplemented two manually operated valves which were kept in the open position. The new design also required that steam admittance valves MS 106A and 107A be kept open with MS 5889 A and B in the closed position. This has the effect of maintaining steam pressure in the lines up to valves MS 5889 A and B.

Thus, while the pressure switches previously had to switch position from tripped to untripped in order to permit AFW system operation, now they remain in the untripped position and only-operate (trip) in the event of a low pressure signal to shut off steam flow to l

the broken line.

Therefore, the AFPT inlet steam pressure interlocks are no longer required for the AFW system to be operable.

3.0 EVALUATION A.

Change to Technical Specification (TS) 3.7.1.2.

The change made to TS 3.7.1.2 separates the action statement resulting from a failed interlock from that resulting from a failure of a portion of the AFW system. We find this acceptable since interlock actuation is not required for AFW system operation.

In addition, the change recoires that en inoperable interlock be returned to operable status within 7 cos or be in hot shutdown within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter. We find this in accordance with Standard Technical Specifications i

and, thus, acceptable.

B.

Change of TS 4.7.1.2 to 4.7.1.2.1 This change separates the demonstration of operability requirements for the AFW system (now in TS 4.7.1.,2.1) from that for the interlocks (added TS Section4.7.1.2.2). We find this change acceptable since the interlocks are now separate frcm the AFW system.

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Deletion of Mention of Interlocks in Previous TS 4.7.1.2.d This change is acceptable since the licensee has demonstrated separability of AFW system operation from the interlocks.

Further, the licensee has maintained the operability requirements for the interlocks in a new TS 4.7.1.2.2.

D.

Addition of TS 4.7.1.2.2 This change identifies the specific operability requirements for the AFW pump turbine inlet steam pressure interlocks separately from the AFW pump ruction pressure interlocks. The TS indicates the requirement for performance of a channel functional test at least once per 31 days and a channel calibration test at least once every 18 months which are the same as previously specifico.

We fino this change consistent with the Standard Technical Specifications and, therefore, acceptable.

E.

Acdition of Sentence to B 3/4 7.1.2 As stated above, the licensee has demonstrated that the steam pressure interlocks are required only for a steam line break and are not required for AFW system operability. Therefore, the adoition of the sentence to this effect in the bases is acceptable.

Based on the above, the staff finds that the changes to the Technical Specifi-cations proposed by the licensee regarding the AFPT inlet steam pressure interlocks are in accordance with the Standaro Technical Specifications and system design requirements and are, therefore, acceptable.

4.0 ENVIRONMENTAL CONSIDERATION

Pursuant to 10 CFR 51.21, 51.32, and 51.35, an environmental assessment and finding of no significant impact has been prepored and published in the Federal Register on April 21, 1989 (54 FR 16176). Accordingly, based upon the environmental assessment, the Commission has determined that the issunnce of this amendment will not have a significant effect on the quality of the human environment.

5.0 CONCLUSION

The staff has concluded, based on the considerations discussed above, that:

(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Connission's regulations, and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor:

H. Wagner Dated: April 25,1989 Attachnent:

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