ML20215M418

Safety Evaluation Supporting Amend 5 to License NPF-36

ML20215M418
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	05/04/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20215M304	List: ML20215M302 ML20215M398 ML20215M418
References
NUDOCS 8705130227
Download: ML20215M418 (3)

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NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 l

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 5 TO FACILITY OPERATING LICENSE NO. NPF-36 LONG ISLAND LIGHTING COMPANY SHOPEHAM NUCLEAR POWER STATION DOCKET NO. 50-322 1.0 INTWDUCTION By letter dated January 21, 1987 (Ref. 1), LILCo the licensee for Shoreham Nuclear Power Station, proposed a change to the Technical Specifications (TS). The main purpose of this change is to reduce challenges to the safety relief valves (SRVs). This would be accomplished by changing the water level setpoint for closure of the main steam isolation valves (MSIVs) and main steam line drain valves (MSLDVs) from level 2 to the lower Level 1. The probability of closing a MSIV due to variation of water level following a r ram would thus be reduced. With the MSIVs open and the main condenser available, prime mover steam for the reactor feed pump turbines will also remain available to allow continued operation of the condensate and main feedwater sys'.em. This will aid in water level recovery before the low level isolation setpoint is reached.

! Should level I be reached, MSIV closure will cause reactor pressure to rise causino the SRVs to open and discharge to the suppression pool. The new heat l load for the suppressier pool will be reduced by the amount of heat picked up l by the main condenser while the level is dropping from level 2 to Level 1.

l l 2.0 EVALUATION The licensee's request to lower the water level trip setpoint for MSIV closure is consistent with staff solutions for NUREG-0737. Item II.K.3.16 " reduction l of challenges and failures of relief valves". In addition, the General l Electric Information Letter, SIL No. 367, also reconnends the lower trip i

setpoint. The staff evaluation of the change in setpoint is discussed below.

2.1 Loss of Coolant Accident (LOCA) and Main Steam Line Break (MSLB) o LOCA The present limiting LOCA is based on the time the hot node remains uncovered. The area corresponding to the break is 85% of the design basis accident (DBA). To justify the setpoint change, LOCA analyses for the 85% DBA, with a staff approved ECCS code was perfonned. The licensee stated that with

! the MSIV isolation occurring at Level 1, and other paraneters unchanged, there I was no change in the peak cladding temperature (FCT) or the total core area i

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uncovered when compared with MSIV isolation at Level 2. With the new level setpnint, the MSIV remained open for three seconds longer than with closure at level 2. The licensee stated that the resulting additional percentage loss of reactor coolant due to the longer closure time is negligible. This is acceptable to the staff since there is no significant change from previous analyses.

For a small break LOCA there is a potential of initiation of MSIV closure at the proposed lower level setpoint. The licensee stated that based on plants similar to Shoreham, there is an increase of about 30 F for a limiting PCT of 1500* F. It was concluded that for this event, the change on the margin of safety was insignificant. We find this acceptable.

o MSLB MSLB was nnt analyzed. Presently, for this event, MSIV isolation occurs prior to Level 2 and closure is initiated by signals other than water level. We find this acceptable since lower level setpoint will not effect the existing MSLB results.

2.2 Abnonnal Operational Transients The transient event for loss of feedwater flow would be affected by the change in the MSIV isolation setpoint from Level 2 to Level 1. This abnonnal operation transient was analyzed. The licensee stated the following:

a. RCIC and HPCI systers which are initiated at Level 2. keep the water above Level 1.

b. The pressurization that occurs with isolation at Level 2 does not occur.

This is acceptable to the staff since there is no adverse effect with regard i to safe reactor operation.

3.0 TECHNICAL SPECIFICATION (TS) CHANGES We have reviewed the following TS changes:

TABLE 3.3.2-1 for isolation actuation instrumentation TABLE 3.3.?-2 for isolation actuation instrumentation setpoints TABLE 3.3.2-3 for isolation system instrumentation respense time l TABLE 4.3.2.1-1 for isolation actuation instrumentation surveillance recuirements Bases for figure E 3/4 3-1 for reactor vessel water levels We conclude that the proposed changes are acceptable.

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4.0 ENVIRONMENTAL CONSIDERATION

This amendment relates to changes .in requirements with respect to the instal-lation or use of a facility component located within the restricted area as *

' defined in Part 20. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may_be released offsite, and that there.is no sienificant increase in. individual or cumulative occupational radiation exposure. The-Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for

- categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of this amendment.

5.0 CONCLUSION

We have reviewed and found acceptable, for the reasons discussed above, the licensees justification for the proposed TS changes to . lower the water level setpoint for the MSIVs and MSLDVs from level 2 to Level 1.

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

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

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Principal Contributor: D. Katze >

s Dated: May 4, 1987