ML20134J146
| ML20134J146 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 11/07/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20134J142 | List: |
| References | |
| NUDOCS 9611150022 | |
| Download: ML20134J146 (6) | |
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UNITED STATES g
j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20eeHW01 l
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION l
RELATED TO AMENDMENT NO. 237 TO FACILITY OPERATING LICENSE NO. DPR-59 i
l POWER AUTHORITY OF THE STATE OF NEW YORK 1
l MiES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333 I
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1.0 INTRODUCTION
By letter dated March 30, 1996, the Power Authority of the State of New York l
(the licensee or PASNY) submitted a request for changes to the James A.
FitzPatrick Nuclear Power Plant Technical Specifications (TSs). Tne change allows for a high pressure trip setpoint which is dependent upon the number of l
safety / relief valves (SRV) which are out of service. Currently, the trip setpoint is 1120 psi which was calculated assuming two SRVs out of service.
The proposed setpoint is 1155 psi. At the time of the original analyses, a lower, seemingly conservative, setpoint was chosen. However, a lower setpoint l
tends to increase the number of unnecessary recirculation pump trips.
Tripping of a recirculation pump, under most conditions, has the undesirable effect of causing cold water to stratify in the lower reactor vessel head.
This stratification can cause a severe thermal transient (approaching or, in i
some cases, exceeding the temperature change rate of 100 *F/hr.) on the l
vessel. Tripping the pump is also a precursor to thermal hydraulic instability. The proposal by PASNY is an attempt to balance the need to trip the recirculation pumps in an anticipated transient without scram (ATWS) and the desire to avoid circumstances leading to undesirable lower plenum thermal stratification and thermal hydraulic' instability.
2.0 EVALUATION The NRC staff evaluation focused on making a determination about whether the ATWS calculations demonstrating that the high pressure setpoint can be increased are valid and acceptable. To this end, the NRC staff issued a request for additional information (RAI) about the supporting analyses performed by General Electric (GE) for PASNY to support the amendment request l
(Ref. 2).
The analyses were performed using the approved REDY code according to the l
procedures established in NUREG-0460. The analyses demonstrate that the peak l
pressure is 100 psi below the limit of 1500 psi with one SRV out of service using the proposed recirculation pump trip pressure setpoint.
REDY analyses were also performed to show the effect of the one out of service SRV by 9611150022 961107 PDR ADOCK 05000333 l
P PDR l
l calculatingthepressureriseassumingpoSRVfailures. This effect was l
confirmed by the staff using the RELAP5 code and was calculated to be 70 psi l
(see Figure 1).
The NRC staff evaluated the proposal to determine if it had any adverse effects on the plant. The RELAP5 audit calculations predict a 100 psi margin to the Reactor Pressure Vessel maximum pressure of 1500 psi and can be thought of as a measure of the conservatism which still remains in the proposed recirculation pump trip setpoint. As part of this effort, the staff also l
calculated the pressure rise with 2 SRV failures and a trip setpoint of 1120 psi (see Figure 1). These analyses re-confirm the validity of the original analyses and establish a baseline value for comparison.
Furthermore, the modification will not effect the peak suppression pool temperature. As a final note, the staff examined the power response to the main steam isolation valve
'ctV) closure ATWS with the different recirculation pump trip setpoint l
and a.
can see from Figure 2, the setpoint change has an insignificant effect the peak power. The impact of the proposed change is, therefore, mi nima'.
cause significant margin still remains.
l Based upon the results of the NRC staff review, the staff has concluded that the proposal to increase the ATWS recirculation pump trip high pressure setpoint from 1120 psi to 1155 psi, assuming that only one SRV is out of service is acceptable. Specifically, the change to TS Table 3.2-7 incorporating the new setpoint is acceptable.
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3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the New York State official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a i
facility component located within the restricted area as defined in i
10 CFR Part 20. The NRC 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 (61 FR 34896). Accordingly, the amendment i
'The code used was RELAPS Mod 3.2 coupled to the NESTLE transient nodal code.
The kinetics input simulated a 1-dimensional model of the core.
See NUREG/CR-5535-V2 i
. 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
The Commission 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, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Anthony Ulses Date: November 7, 1996 I
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REFERENCES 1.
Letter from H. P. Salmon (PASNY) to USNRC, " Proposed Change to the l
Technical Specification Regarding ATWS Recirculation Pump Trip," May 30, j
1996.
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2.
Letter from C. H. Stoll (GENE) to R. Penny (PASNY)," "ATWS Analysis for Recirculation Pump Trip Setpoint Changes," May 23, 1996.
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Figure 1 Demonstrates effect on peak pressure from assuming 1 out of service SRV.
The difference in pressure is approximately 70 psi.
MSIV Closure ATWS Peak Pressure DOE RELAPS 1-D Kinetics 1500.0 1400.0 l
n
.5 t
1300.0 o.
N E
5 1200.0 l
O--00 Valw Failures (Tdp 911% pd) x-K 1 Valw Failures (Tdp 911% pd) 1100.0 C Oz valw Failures (Tnp e 1120 psi)
P 1000.0 O.0 10.0 20.0 30.0 Time (s) m. -
Figure 2 Note that the peak fission power is essentially unaffected by the change in the RCP trip setpoint.
Fission Power MSIV Closure ATWS REL4P5 Mod 3.2 to/ Nodal Kinetics 250.0 U
2:
2 C 01120 psi Set-Point i
~ 200.0 0-01155 psi Set-Point o
E t> 150.0
?
Note that MSIV closure time varies e
.S
.5 100.0 w
L 50.0
~
O-0.0 O.0 10.0 20.0 30.0 Time (s)
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