ML20090D727
| ML20090D727 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 04/03/1975 |
| From: | Ross D JERSEY CENTRAL POWER & LIGHT CO. |
| To: | Anthony Giambusso Office of Nuclear Reactor Regulation |
| References | |
| AO-50-219-75-08, AO-50-219-75-8, NUDOCS 8303020315 | |
| Download: ML20090D727 (4) | |
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Jersey Central Power & Light Company MADISON AVENUE AT PUNCH BOWL ROAD
- MORRISTOWN, N.J. 07960
- 201-539-6111
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'E Mr. A. Giambusso Director, Division of Reactor Licensing 4
g Office of Nuclear Reactor Regulation D
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United States Nuclear Regulatory Commission g
Washington, D. C. 20555
Dear Mr. Giambusso:
Subject:
Oyster Creek Station Docket No. 50-219 r
Abnormal Occurrence Report No. 50-219/75-8 The purpose of this letter is to forward to you the attached abnormal occurrence report in compliance with paragraph 6.6.2.a of the Technical Specifications.
Enclosed are forty copies of this submittal.
Very truly yours, b-b4L m
Dor.ald A. Ross, Manager
, Generating Stations-Nuclear es Enclosures cc:
Mr. J. P. O'Reilly, Director
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Office of Inspection and Enforcement, Region 1 h
, CP 3847 gj3020315750403 s
ADOCM 05000219 PDR f
COPY SENT REGION
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px Jersey Central Power & Light Company v MADISON AVENUE AT PUNCH BOWL ROAD
- MORRISTOWN, N.J. 07960
- 201-539-6111 m uu n <* rnu
{ Public Utihties Corpore 9on General svara.
OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. 50-219/75-8 Report Date April 3, 1975 O_ccurrence Date March 25, 1975 Identification of Occurrence Violation of the Technical Specifications, paragraph 3.10. A.
Power operation continued with the average linear heat generation rate of four fuel assemblies in excess of the maximum average LilGR shown in Figure A-1, Appendix A, to an
" Order for Modification of License" issued on December 27, 1974 by Edson G. Case, Acting Director, Office of Nuclear Reactor Operation, Nuclear Regulatory Commission. This event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1.15.B.
Conditions Prior to Occurrence The plant was undergoing load change during routine power operation with major parameters as follows:
Power:
Electric, 644 MWe Reactor,1848. 3 MWt Flow:
Total Recirculation, 156,000 GPM 6
Feedwater, 6.88 x 10 lb/hr Stack Gas: 40,500 pci/sec Description of Occurrence On Friday, March 21,1975 at 2200, plant power was reduced to 550 MWe to accom-modate core flux shaping. During this period, the control rod group (Group 23),
one rod cf which is near LPRM location 36-17, was withdrawn from pcsition 32 to position 36.
At this time, various locations of the core were monitored,
Abnormal Occurrence Report No. 50-219/75-8 Page 2 including location 36-17, and it was determined that power level increases with recirculation flow could commence. On Sunday, March 23, 1975 at 1000, with plant power at 623 MWe, various locations of the core were again monitored using the Traversing Incore Probe (TIP) System.
It was found that the APLIIGR for the Type II fuel around LPRM location 12-41 was 96*6 of its limit. At this time, control rod group 23 was inserted from position 36 to position 34 to reduce the APLilGR of 12-41.
On Tuesday, March 25, 1975, a power distribution calculation was performed and it calculated an APLilGR of 11.00 Kw/ft for assembly A052 which is 104.0% of its limit of 10.57 Kw/ft at the local exposure of the fuel involved.
Apparent Cause of Occurrence The cause of this occurrence was the failure to properly monitor the reactor core.
Following any movement of control rods, it is the responsibility of the Technical Engineering Department to determine the core LPRM locations which monitor the limiting APLilGR's for each type fuel.
Following the power shaping of March 21, 1975, there was a judgment error made in selecting which Type II fuel to monitor. This error resulted in operating four (4) Type II fuct assemblies in excess of their APLilGR limit. The error was detected from the cora power distribution results following a full core neutron flux scan with the TIP system.
Analysis of Occurrence In the event of a loss of coolant accident (LOCA), the four (4) fuel assemblies might have exceeded the 2200*F peak clad temperature and 17% local metal / water reaction limit as specified in 10CFR50, Appendix K, and calculated using the General Electric blowdown analysis submitted in support of the Technical Specifi-cation change dated August 22, 1974, and subsequently modified by the above mentioned AEC order of December 27, 1974. The significance of this event was minimized by the small extent of the limit excess and by the relatively short time duration.
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Corrective Action The average planar linear heat generation rate of the affected fuel was reduced to 9.92 Kr/ft (93.8% of its limit) by insertion of control rod group 23 from position 34 to position 32 at approximately 1800 on March 25, 1975.
The Technical Supervisor will reevaluate the core monitoring requirements during power level changes and make recommendations to the Technical Engineer to prevent recurrence.
Failure Data Fuel Assembly:
JCA052 JCA147 JCA145 JCA086 Bundle Average l
Exposure:
16,500 mwd /mt 16,500 mwd /mt 16,500 mwd /mt 16,500 mwd /mt Local Exposure:
18,500 mwd /mt 18,500 mwd /mt 18,500 mwd /mt 18,500 mwd /mt Core Location:
37-36 37-18 15-36 15-18
O o
Abnormal Occurrence Report No. 50-219/75-8 Page 3 Previous abnormal occurrences involving operation above APLHGR limits are as l
follows:
1.
Abnormal Occurrence Report No. 50-219/73-26 1
2.
Abnormal Occurrence Report No. 50-219/74-45 3.
Abnormal Occurrence Report No. 50-219/75-4 i
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