ML20055C885
| ML20055C885 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 06/18/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20055C884 | List: |
| References | |
| NUDOCS 9006250334 | |
| Download: ML20055C885 (3) | |
Text
.,
e,,
@ 180
.y J,.
- o, UNITED STATES
'!I NUCLEAR REGULATORY COMMISSION o
h WASHING) ON, D. C. 20S$5 3.,*.../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.140 1
TO PROVISIONAL OPERATING LICENSE NO. DPR-16 i
GPU NUCLEAR CORPORATION AND JERSEY CENTRAL POWER & LIGHT COMPANY OYSTER CREEK NUCLEAR GENERATING STATION DOCKET NO. 50-219
1.0 INTRODUCTION
By letter dated March 19,1990 (Ref.1), GPU Nuclear Corporation (the licensee) requested changes to the Oyster Creek Technical Specifications (TS). The TS change proposes to allow an idle recirculation loop to be isolated. Oyster Creek is currently authorized to continue power operation if one of the five-t recirculation loops is taken out of service:provided the idle loop is not isolated. The allowed configuration is the loop discharge valve closed and the suction and discharge bypass valves open. The request would allow the discharge bypass valve and suction valve to be closed in addition to the discharge valve. thus completely isolating-the loop. The proposal will allow
-operation with only the-discharge valve closed or with all valves. closed.
GPU proposed the TS change as a result of a Technical Specification-required shutdown on February 6,1990. The shutdown was required when the unidentified leak rate approached the Technical Specification'11mit of 5_ gallons per minute. The leakage =was due to a failed recirculation pump seal on recirculation loop A.
If the pump could have been isolated, the leakage might have been reduced and a shutdown averted. The ability to isolate a-1 recirculation pump would. prevent unnecessary shutdowns in the' future.
2.0 EVALUATION E
There are two main differences in the LOCA analysis for four-recirculation-loop l
operation', as compared to the normal five-loop case:
~(a) With fewer operating loops, each functioning loop will be carrying a i
higher percentage of the initial core recirculation flow.
If a break in l
one loop occurs, then a faster core flow coastdown rate will result, L:
which could yield an earlier boiling transition time, 9006250334 900618 hDR ADOCK 05000219 PDC
-~
4.
si l4;.
(b)
If the inactive loop is isolated by closing the inactive loop suction and discharge valves, there will be reduced coolant inventory, which may lead to earlier core uncovery during a LOCA.
The LOCA analyses for four loop operation were performed using the "0yster Creek - SAFER /COREC00L/GESTR LOCA" methodology (Ref. 2), which has been approved by the staff (Ref. 3). GE performed the analyf es with one out of service loop's inventory subtracted from the water available for blowdown.
The small break (0.01 ft2) and the DBA were calculated with the reduced inventory. The effects of faster core flow coastdown rate were also considered in the analyses. The results from the analysis demonstrate that 10 CFR 50.46 criteria for peak cladding temperature and maximum cladding oxidation are met, provided that an appropriate MAPLHGR multiplier is applied to the initial reactor power conditions. These multipliers are given below:
Fuel Type Exposure Range MAPLHGR Multiplier P8x8R E.L 15.0 GWd/MTV 0.99 P8x8R E > 15.0 GWd/MTU 0.98 GE8x8EB All Exposures 0.98 In addition to the GE fuel assemblies, there are 29 ANF fuel assemblies which were loaded in Cycle 10 or earlier that are now located on the cora periphery.
The ANF four loop analysis does not address an isolated recirculation loop.
The NAPLHGR multiplier of 0.98 is also applied to ANF fuel. This is acceptable.
When a recirculation loop is fully isolated at power, the isolated portion between the suction and discharge valves will cool to near ambient temperature.
Before the pump in the fully isolated racirculation loop can be restarted, the loop temperature must be warmed to within 50*F of the bulk coolant temperature in order to avoid the injection of cold water into the reactor core to prevent L
a transient and to avoid thermal stresses to the reactor vessel nozzles and CRD l
housings. This requirement cannot be satisfied with the current system configuration.
Therefore, a fully. isolated loo) will not be restarted once it is isolated unless the reactor is in the cold slutdown condition. The suction valve, discharge valve and discharge bypass valve in the fully isolated loop will be in the closed position and the associated motor breakers shall be I
opened'and defeated to prevent cold water injection into the vessel.
This is l
acceptable.
3.0 TECHNICAL SPECIFICATION CHANGES Sectjof 3.3.F.2 (a) MAPLHGR multiplier of 0.98 is applied to APLHGR sections in 3.10.A.
This change is supported by the analytical results that demonstrate no violation to the fuel integrity acceptance criteria and the fuel performance criteria of 10 CFR 50.46. This is acceptable.
(b) The idle recirculation pump MG set circuit breaker will be tagged out.
This will prevent inadvertent startup of idle loop. This is acceptable.
(c).The idle recirculation loop suction valve, discharge valve and discharge bypass valves will be kept closed to prevent pump seal leakage. Their motors breakers will be. tagged out. This will also prevent inadvertent startup of idle loop. This is acceptable.
(d) The isolated loop will not be returned to service unless the reactor is in the cold shutdown condition. This will prevent thermal stress of the RCS. This is acceptable.
1 Bases' Sections 3.3 and 3.10 The revisions properly reflect the affected changes and hence the changes are acceptable.
The proposed request to isolate the idle recirculation 1)op Completely is 4
acceptable as discussed in Section 2.0.
4.0 ENVIRONMENTAL CONSIDERATION
Pursuant to 10 CFR 51.21, 51.32, and 51.35, an environmental assessment and finding of no significant impact have been prepared and published in the Federal Register on June 14, 1990 (55FR 24170
).
Accordingly, based upon the environmental assessment, we have determined that the issuance of the amendment will not have a significant effect on the quality of the human environment.
5.0 CONCLUSION
The staff has concluded, Scsed on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the will not be endangered by operation in the proposed manner, and (2) public 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 nor to the health and safety of the public.
6.0 REFERENCES
1.
Letter dated March 19, 1990 from E. E. Fitzpatrick Vice President and 4
Director, Oyster Creek to USNRC.
2.
NEDE-31462P, "0yster Creek Nuclear Generating Station SAFER /COREC00L/GESTR
- Loss of Coolant Accident Analysis," August 1987.
3.
Letter from A. Thadani (NRC) to H. Pfefferlen (GE), dated May 11, 1987.
Dated: June 18, 1990 l
Principal Contributor: George Thomas l
b
.