ML20083R879
| ML20083R879 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 02/07/1975 |
| From: | Finfrock I JERSEY CENTRAL POWER & LIGHT CO. |
| To: | Goller K Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20083R856 | List: |
| References | |
| NUDOCS 8304050049 | |
| Download: ML20083R879 (3) | |
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MADISON AVENUE AT PUNCH BOWL ROAD
- MORRISTOWN, N.J. 07960
- 201539-6111 annane or r.e General g.
, Public Utilities Corporation February 7, 1975
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Mr. K. R. Goller g-)'
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Assistant Director for Operating Reactors W m'*
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Division of Reactor Licenaing Office of Nuclear Reactor Regulation Washington, D. C. 20555
Dear Mr. Goller:
Subject:
Oyster Creek Nuclear Generating Station Docket No. 50-219 Snubber Service Life and Reliability In his October 1,1973 letter, Mr. Donald J. Skovholt requested the
,du.:.1Liel of a prcposi.J prograi t5 improvc' sr.ubbcr (i.c., hydr ulic :h::h :.;!
sway arrestor) service life and reliability and proposed Technical Specifi-cation changes to incorporate a snubber surveillance program. This request was accompanied by the specification to replace all snubber seal material with
" material demonstrated to be compatible with the hydraulic fluid at the oper-ating environment," and the specification of snubber inspection intervals (i.e.,
a 120 cy maximum inspection interval for snubbers inaccessible during reactor operation and a 30-day maximum inspection interval for snubbers accessible during reactor operation).
During the September 1973 shutdown of the Oyster Creek Nuclear Generating Station, all snubbers within the Oyster Creek drywell and most of the snubbers in the Reactor Building were rebuilt with seals made of molded poly-crethane, viton, and ethylene propylene.
In December of 1973, General Electric Company reported that snubber seal tests indicated that ethylene propylene (EP) seal material was best suited for use in Bergen-Paterson snubbers. Additional tests by the Packer Seal Company demonstrated the ability of EP seal material to withstand the operating environment of the drywell (ref. Mr. D. A. Ross's letter of November 8,1974 to Mr. K. R. Goller on " Snubber Temperature and Radiation Environment"). A program to rebuild snubbers with EP seals was started, and at present all drywell snubbers contain only EP seals and Reactor Building snubbers have been rebuilt to a large extent with EP seals. To date, the EP seal performance has been exec 11cnt. The detailed inspection procedures presented in the letter of December 7,1973 from Mr. D. A. Ross, Manager of Generating Stations-Nuclear, to Mr. A. Giambusso have shown that no snubbers have failed f.D 'p h 16k9 8304050049 750708 Y
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Mr. Goller February 7, 1975 due to EP seal deterioration. The failures of snubbers containing EP seals have been the result of mechanical failures such as main piston rod burrs cutting
-the main cylinder. shaft U-cup.
(Ref. Abnormal Occurrence Report No. 50-219/74-40.)
Rebuilding and inspection procedures have been modified to identify and min'inize such mechanical failures. The incorporation of the EP seals in the snubbers has significantly improved snubber service life and reliability.
Therefore,
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inspections of those snubbers in the drywell will henceforth be dos only when-the drywell miis't be entered and the snubber inspection has' not bee'n performed within the previous 120 days. Defective units will be repaired or replaced before returning to power. Only EP seals will be used in' repairing and rebuild-ing these units.
Snubbers that are not in the drywell and are not ' accessible during reactor operation will be inspected when they are accessible but not more frequently than 120-day intervals.
Defective units will be replaced or l
repaired only with EP seals.
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Snubbers in the Reactor Building (i.e., those accessib1E 'Jur$ng reactor operation) will be inspected at least every 60 days.- This inspection will' include a fluid level determination and a general visual examination. Units leaking fluid severely will be removed to determine the cause of the leakage.
Repaired and/or rebuilt replacement units for the R$actbr Building snubbers will 4
contain only EP seals except for the main shaft packing. seal. EP main shaft i
packing seals are not available for some of the snubber models currently in use j
in the Reactor Building. Operating experience has shown that this 60-day s.
inspection interval is sufficient to detect conditions that could lead to snubber inoperability (e.g., leaking).,
The current snubber sdrveillance program is part of the periodic-Oyster Creek maintenance activities. This new inspection program (i.e.t inspection during drywell accessibility if not performed within previous 120 days',
etc.) is currently being i6c15ded in the Oyster Creek Preventive Maintenhnce Program.
It is felt that this type of inspection program is best, suited for the maintenance program rather than the Technical Specifications.,It0 inclusion in the Preventive Maintenance Program safeguards the proper implementation of the inspection program. A proposed Technical Specification change t(incorporate the snubber inspections into the Oyster Creek Technical SpBei'ficiiions;i's' there-fore.not included.,
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While tests and experience have shown that the EP seal mate' rial is a viable solution to the snubber seal-deterioration problem, Jersey-Central Power G.
Light Company believes that a better solution is the replacement. of. the hydraulic snubbers with mechanical units. Analysis and tests have shown that the seismic.
j response characteristics of the mechan'ical snubbers are equivalent or better ?
than those of the hydraulic snubbers, and it, of course, does not have the seal deterioration problem. The Generation Engineering DepartmentMf' Jersey Central Power 6 Light Company, therefore, is' in the process, of purchasing mechanical snubbers.
It is anticipated that' procurement procedures will be completed so that some of the drywell h^ydrauli,c snubbers:can:be replaced with mechanical i
- units during the Spring,1975Jtefueling Outage. When thic is.done,~those units.
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removed from the drywell?(i'.'e d those containingfEP sea'15jonly) Qwill be used n
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February 7, 1975 to replace the snubbers in the Reactor Building.
This will allow the surveillance interval for those Reactor Building snubbers containing all EP seals to be increased from 60 days to 120 days or greater.
3 Functional checks of the mechanical units in the drywell will be made in accordance with the specification of the Oyster Creek Station Inservice Inspection Program.
1 Very truly yours, k c/jj// / flY'I U
U Ivan R. Finfrock..Jr.
Vice President es l
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OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. S0-219/74/3 Report Date:
January 24, 1974 Occu ence Date:
January 13, 1974 Identification of Occurrence:
Failure of Hydraulic Shock and Sway Arrestors on one Core Spray System and on both Isolation Condenser Systems.
This event-is considered to be an abnormal occurrence as defint;d in the Technical Specifications, paragraph 1.15D.
Conditions Prior to Occurrence:
The plant was in a cold shutdown condition with reactor coolant at <212*F.
Description of Occurrence:
During the required inspection of the Bergen Paterson 11SSA-10 units in the primary containment, five units were discovered to be devoid of fluid.
They were located as follows:
3 "A" Isolation Condenser i
"B" Isolation Condenser 1 - Core Spray System No.'2 Apparent Cause of Occurrence:
The cause of snubber inoperability was due to a loss of hydraulic' fluid.
Disassembly of each of the inoperable' snubbers has revealed no visually
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obvious deterioration of the seal material except for some brittleness.
Analysis of Occurrence:
The safety si'inificance of this occurrence was a partial loss of the seismic restraining ability for thetwo affected systems. Had the plant -
. suffered a^ design bases carthquake, the probability that these two systems-
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would have suffered structural damage l was increased.
Corrective Action:
- The failed units were replaced witi units that were rebuilt with ethylene propylene (Parker; Grade ~E652-90)-seal material.
Four of the' inoperable:
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Abnormal Occurrence. Report No. 50-219/74/3 Page 2
_ units were located above -the biological shicid, a relatively hot area in the. containment, and had been rebuilt in September 1973 with molded polyurethane and viton type seal material. All of the units in that area, regardless of condition, have been replaced with units rebuilt with the ethylene propylene type material.
Failure Data:
Manufacturer:
Bergen Paterson
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-IISSA-10 Serial Nos.:
487517 487487 477376 470924 469962 4
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MADISON AVENUE AT PUNCH BOWL ROAD
- MORRISTOWN, N.J.07960
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Mr. A. Giambusso
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Dear Mr. Giambusso:
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Subject:
Oyster Creek Station Docket No. 50-219 Abnormal Occurrence Report No. 50-219/74/3 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,
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cc: Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations, Region I L
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Initini Tdicph;na Dato cf Report Dato:
,l/14/74 Occurr;nro t 1/13/74 s
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.,Inidial britten Report Date:
1/14/74 Occurren ce:
1700 OYSTER CREEK NUCLEAR GENERATING STATION
' FORKED RIVER, NEW JERSEY. 08731 Abnormal Occurrence Report No. 50-219/74/ 3 IDENTIFICATION Violation of the Technical Specifications, paragraph N/A OF OCCURRENCE:
Failure of Hydraulic Shock and Sway Arrestors on one Core Spray System and two Isolation Condenser systems.
This event is considered to be an abnormal occurrence as de-fined in the Technical Specifications, paragraph 1.1SD CONDITIONS PRIOR TO OCCURRENCE:
Steady State Power Routine Shutdown Hot Standby Operation X
Cold Shutdown Load Changes During Refueling Shutdown Routine Power Operation Routine Startup Other (Specify)
Operation The plant was shutdown with reactor coolant at <212 F.
DESCRIPTION During the required inspection of.the Bergen Paterson HSSA-10 0F OCCURRENCE:
units in the primary containment, five units were disccvered to be devoid of fluid. They were located as follows:
3 "A" Isolation Condenser 1
"B" Isolation Condenser 1 - Core Spray System #2
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. s APPAREhT CAUSE Design Procedure OF OCCURRENCE:
Manufacture Unusual Service Condition Installation /
Inc. Environmental Construction Component Failure Operator Other (Specify)
The cause of snubb'er inoperability was due to a loss of hydraulic fluid. The cause of fluid loss is presently under investigation.
ANALYSIS OF The safety significance of this occurrence was a partial OCCURRENCE:
Icss of the seisnic restraining ability for the two affected systems.
!!ad the plant suffered a design bases carthquake, the probability that these two systems would hnve suffered structural damage was increased.
CORRECTIVE The failed units were replaced with units that were rebuilt ACTION:
with ethylene propylene (Parker Grade E652-90) seal material.
FAILURE DATA:
Manufacturer:
Bergen Paterson Type: IISSA-10 Serial Nos.:
487517 487487 477376 4',0924 4699$2 0
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-To:
James P. O'Reilly Directorate of Regulatory Operations Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 From:
Jersey Central Power 5 Light Company Oyster Creek. uclear Generating Station Docket #50-219 N
Forked River, New Jersey 0S731 Subj ect:
Abnormal Occurrence Report No. 50-219/74/ 3
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The folicwing is a preliminary report being submitted in compliance with the Technical Specifications paragraph 6.6.2.
Preliminary Approval:
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1/14 /74 J. T. Carro ll, J r.O' Date v-cc:
Mr. A. Gintbuss i
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