ML20236D723
| ML20236D723 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 03/15/1989 |
| From: | Fitzpatrick E GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8903230238 | |
| Download: ML20236D723 (2) | |
Text
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GPU Nuclear Corporation NucIear gitan*388 o
Forked River, New Jersey 08731-0388 609 971-4000 Writer's Direct Dial Number:
March 15,1989 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555
Dear Sir:
Subject:
Oyster Creek Nuclear Generating Station Docket No. 50-219 SS0MI Inspection-Additional Information
References:
- 1) GPUN Calculation No. C-1302-212-5360-041, Rev. O,
" Core Spray System Calculation - Yalve Stroke Time vs. Flow Area", 12/14/88
- 2) GPUN Calculation No. C-1302-212-5360-013, Rev.1 "0yster Creek System Hydraulic Analysis",1/21/85
- 3) GPUN response to NRC Bulletin No. 88-04, dated 7/11/88
- 4) GPUN Calculation No. C-1302-212-5360-043, Rev. O,
" Core Spray System Flowrate vs. Injection Valve Posi tion",1/11/89 The purpose of this letter is to provide additional information regarding Core Spray System valve o Modification Inspection (pening times.
During the Safety System Outage SS0MI), a discrepancy was identified in that the In-Service Test (IST) program contains acceptance criteria for opening times of Core Spray System injection valves of less than or equal to 22 seconds.
The opening time specified in the Updated Final Safety Analysis Report (UFSAR), however, is less than or equal to 20 seconds. 'The inspection team requested that GPUN evaluate the IST values to ensure that with the increased opening times, the Core Spray System would still perform its intended function.
GPUN responded to the SSOMI concerns by letter dated January 12, 1989.
Subsequently, NRC contacted GPUN for additional information regarding the basis for the conclusion that a 22 second opening time is acceptable.
The reference calculations were provided to the NRC resident inspector for review.
Based on recent discussions, GPUN agreed to provide additional information to clarify the methodology that was used to reach this conclusion.
The current Appendix K analysis performed for Oyster Creek takes credit for a Core Spray injection valve opening time of 20 seconds as indicated in the Updated FSAR. To ensure adequate core spray flow will be available, in accordance with this assumption, a calculation was performed (Reference 1) to determine the percent open flow area that would exist at 20 seconds.
The results indicate that the flow area at 20 seconds would be 94% percent of the full open flow area.
8903230238 890315 pl ADOCK0500g9 DR GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation '
.- Reference 2 provides the analysis for Reactor Coolant System (RCS) pressure and the corresponding flowrate at that pressure for Core Spray Systems I and II. This delivered flowrate accounts for a minimum recirculation flow of 300 GPM. However, the results of recent calculations i
performed by GPUN in response to NRC Bulletin 88-04 (Reference 3) conclude that the actual minimum flow value, based on installed flow orifice size, is approximately 100 GPM. Correcting the delivered flowrates for this 1
approximate 200 GPM difference, and interpolating between the specified Reference 2 values for 110 psig, results in expected flowrates of.
approximately 4100 GPM for System I and 4000 GPM for System II. With a 94.
percent full open flow area, the calculated flowrates are 3854 GPM for System I and 3760 for System II, which are within the' required values specified in l.
the bases for Technical Specification section 3.4.
1 l
It should be noted that the values calculated above are conservative since a more realistic analysis of the change in head loss resulting from the
=
valve not being' fully open indicates that the increase in system resistance is negligible when the gate valve is at the 20 second stroke. position vs. the 22 second position (Reference 4).
In conclusion, these calculations demonstrate that after 20 seconds the parallel injection valves will have opened sufficiently to pass greater than the required flowrate to the reactor.
If you require further information regarding these calculations, please contact Kathy Barnes. at (609) 971-4390.
Very truly yours, l
E. E. Fitzpa ick
(
Vice President and Director Oyster Creek EEF/KB/aa l
(0704A:02) cc:
Mr. Alexander W. Dromerick, Project Manager l
U.S. Nuclear Regulatory Commission 1
Division of Reactor Projects I/II l
Washington, DC' 20555 NRC Resident Inspector 0yster Creek Nuclear Generating Station Forked River, NJ 08731 1
l'.
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