ML20207E684
| ML20207E684 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 12/19/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20207E679 | List: |
| References | |
| NUDOCS 8701020256 | |
| Download: ML20207E684 (4) | |
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UNITED STATES
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N0.103 TO FACILITY OPERATING LICENSE N0. DPR-59 POWER AUTHORITY OF THE STATE OF NEW YORK JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333
1.0 INTRODUCTION
By letter dated June 25, 1986, the Power Authority of the State of New York, licensee for the James A. Fitzpatrick Nuclear Power Plant, proposed a change to the Technical Specifications (TS).
This change would lower the reactor water level setpoint for closure of the main steam isolation valves (MSIVs), main steam line drain valves (MSLDVs) and reactor water sample line isolation valves (RWSVs) from Level 2 to Level 1.
The main purpose of this change is to reduce challenges to the safety relief valves (SRVs). The probability of closing the MSIVs due to variation of water level following a scram vould be reduced as a result of this change and reactor pressure would Le maintained below the SRV setpoint pressure by the turbine bypass valves for a longer period of time. The main cor. denser would then continue to act as a heat sink until Level 1 is reached. With the MSIVs open and the main condenser available, the relief valves would not be challenged.
Should Level I be reached, MSIV closure would cause reactor pressure to rise causing SRV actuation and discharge to the suppression pool. The resulting heat load on the suppression pool produced by the delayed SRV discharge would therefore be reduced.
The change in MSIV water level setpoint from Level 2 to Level I will not affect the initiation point of the High Pressure Core Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) systems, which will remain at Level 2.
However, with the MSIVs now remaining open until Level 1 is reached, steam for the reactor feed pump turbines would remain available for an additional period of time.
For certain operating transients, this would give the operator the option of adding water to the reactor vessel via continued operation of the condensate and feedwater systems rather than by use of the HPCI and/or RCIC systems. Since the HPCI and RCIC turbines exhaust to the suppression pool, the heat load on the suppression pool would be reduced.
The instruments which set the level for MSIV closure also initiate closure of the MSLDVs and RWSVs. Hence the level setpoint for the MSIVs, MSLDVs and RWSVs would all be lowered from level 2 to Level 1 as a result of the proposed change.
8701020256 861219 DR ADOCK 05000333 PDR
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2.0 EVALUATION The licensee provided a General Electric (GE) report entitled " Safety Review of Safety Relief Valve Simmer Margin Analysis and Water Level Setpoint Change for James A. Fitzpatrick Nuclear Power Plant," Rev.1.
This report evaluated the change in reactor water level isolation setpoint from Level 2 to Level 1 for the MSIVs, MSLDVs and RWSVs. The staff evaluation of the change in setpoint level for each group of valves and the proposed TS changes follows.
2.1 Main Steam Isolation Valves'(MSIVs)
The effect of change in level setpoint for the MSIVs was considered for abnormal operational transients, loss of coolant accidents (LOCAs),
including a main steam line (MSL) break, and anticipated transients withoutscram(ATWS). The specific events analyzed, with the exception of ATWS, were the same as those previously considered in Chapter 14 of the FitzPatrick Final Safety Analysis Report (FSAR).
Of the abnormal operational transients discussed in the FSAR, only two were affected by the level setpoint change; i.e., the loss of feedwater flow transient and a feedwater controller failure at maximum demand.
For both these events, the reactor feed pump would be unavailable and HPCI and RCIC would be initiated for core cooling. The licensee found that the setpoint change would not cause: a) a reduction in the minimum critical power ratio, b) an increase in peak reactor vessel pressure, c) an increase in radiation release, d) equipment damage, e) a reduction in plant shutdown capability, or f) a decrease in core cooling capability.
The licensee, therefore, concluded that no new safety concerns are introduced by the setpoint change with regard to abnormal operating transients.
Large and intermediate LOCA events were qualitatively analyzed. For these events, there would be a rapid depressurization and inventory loss within the reactor vessel, resulting in a fast actuation of the MSIVs.
The reactor feed pump would be unavailable in this case and the core would be cooled by the low-pressure Emergency Core Cooling Systems. The licensee reported that the MSIVs would close before any fuel failure could occur, that the lower MSIV setpoint would not increase the reactor core inventory loss or radiation loss to the environment, and that the maximum average planar linear heat generation rate (MAPLHGR) would not be changed. Thus, the licensee concluded that the setpoint change would tot affect the design basis accident (DBA) for large and intennediate LOCA events.
In the event of a small break LOCA, with the condensate and feedwater system unavailable, thera is a potential for initiation of MSIV closure at the proposed lower level setpoint. Upon MSIV closure, safety relief valve actuation would follow. This event was analyzed using the approved GE Appendix K evaluation model for the lowered MSIV setpoint. The licensee stated that the highest peak cladding temperature would be substantially less than the 2200*F limit. Therefore, the setpoint change would have no effect on the limiting MAPLHGR.
. The licensee also reported that a MSL break would be unaffected by)the setpoint change since other MSIV isolation signals (e.g. high flow would occur well before a low reactor water level isolation signal.
For the ATWS event, the licensee concluded that the lowered setpoint level for the MSIVs would not introduce any new safety concerns. This is based on the fact that the recirculation pump trip at Level 2 results in a significant decrease in reactor power, and the HPCI and RCIC systems initiation at Level 2 would provide makeup water to the reactor vessel.
We have reviewed the licensee's analysis of the effects of a lowered MSIV water level setpoint on abnormal operational transients, LOCAs and the ATWS event and find the above determinations appropriate and conclusions acceptable.
2.2 Main Steam Line Drain Valves (MSLDVs)
The MSLDVs are considered part of the MSL isolation system. The drain lines which they isolate are normally closed and represent a flow area of about 1.8% of the MSL. The licensee concludes that the amount of radiation release and inventory loss through the MSLDVs will be insignificant when compared to that through the MSIVs when the setpoint is lowered from level 2 to Level 1.
We find the above determinations appropriate and conclusions acceptable.
2.3 Reactor Water Sample Valves (RWSVs)
In the event of a decreasing water level, the RWSVs presently isolate the sample line at Level 2 to reduce inventory loss. The RWSVs are 3/4 inch in size. The licensee states that the additional inventory loss through this line, in going from level 2 to Level 1, would be insignificant. They also conclude that, since the lower level setpoint for the MSIVs will not increase the amount of radiation release for a DBA (as discussed above), isolation of the RWSVs at Level I will not affect the calculated radiation doses. We concur with these findings.
2.4 Technical Specification Changes The licensee proposed to change TS Tables 3.2-1, 3.7-1 and Bases 3.2 to reflect a change in setpoint from level 2 to Level 1 for the MSIVs, MSLDVs and RWSys. We find the above determinations appropriate and conclusions acceptable.
I
. 3.0
SUMMARY
The licensee has proposed TS changes which would lower the reactor water level setpoint from Level 2 to Level 1 for initiation of closure of the MSIVs, MSLDVs and RWSVs.
In the event of a scram, the lower setpoint would allow steam flow from the reactor vessel through the bypass valves to the condenser for a longer period of time. Also, steam would remain available longer for continued operation of the reactor feed pump.
These are advantages which result in fewer challenges to the SRVs, a reduced heatup of the suppression pool, and in certain circumstances, a preferred source of water addition to the reactor vessel via the reactor feed pump. We therefore, find the licensee proposed TS changes to be acceptable.
4.0 ENVIRONMENTAL CONSIDERATION
S This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR 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 significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, the 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 or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
We have 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 Commission's regulations, and the issuance of the amendment will not be inimical to l
the common defense and security or to the health and safety of the public.
Principal Contributor:
D. Katze Dated:
December 19, 1986 1
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