ML19319E137
| ML19319E137 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 01/21/1974 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Deyoung R US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 717, NUDOCS 8003310656 | |
| Download: ML19319E137 (4) | |
Text
F AFC DISTP 'UTION FOR PART 50 DOCYET MATER 7~,
(TDiPORARY FORM)
CONTROL NO:
717 1
FILE:
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FROM:
DATE OF DOC DATE REC'D LTR MEMO RPT OTIER S:cramento Municipal Utility Diatrict Sccramento, California 95813 J. J. Mattimoe 1-21-74 1-25-74 X
TO:
SENT LOCAL PDR X
Mr. DeYoung i signed CLASS UNCLASS PROP INFL INPUT NO C'IS REC' D DOCKET NO:
XXXX 1
- 50-312 DESCRIPTION:
ENCLOSURES:
Ltr ro our 12-5-73 ltr.... submitting summary of thn detailed survey of all Bergen-Paterson cnubb rs at Rancho Seco..........
b hh ACUOWiDGED PLANT NAME:
Rancho Seco FOR ACTION /IUFORMATION 1-28-74 AB BUTLER (L)
ACIMENCER(L)
ZIDIANN(L)
REGAN(E)
W/ C pies W/5 Copies W/ Copies W/ Copies CLAPX(L)
STOLZ(L)
DICIGR(E) t W/ Copies W/ Copies W/ Copies W/ Copies GOLLER(L)
VASSALLO(L)
IQIIGHTON(E)
W/ Copies W/ Copies W/ Copies W/ Copies KNIEL(L)
SCHEMEL(L)
YOUNGBLOOD(E)
W/ Copies W/ Copies W/ Copies W/ Copies
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7 INTERM L DISTRIBUTION
% G FIT V TECH REVIEW DENTON A/T IND LIC ASST BRAIniAN AEC PDR VIENDRIE GRI;iES y
OGC, ROOM P-506A SCHROEDER GAMMILL DIGGS (L)
SAL'I2 MAN MUNTZING/ STAFF
, MACCARY KASTNER GEARIN (L)
B. HURT CASE KNIGHT BALLARD yGOULBOURNE (L)
PLANS jGIAllBUSSO PAULICKI SPANGLER LEE (L)
- MCDONALD BOYD SHA0 MAIGRET (L)
DUBE w/ Input MOORE (L)(INR)
STELLO ENVIRO SERVICE (L)
,DEYOUNG(L)(PWR)
HOU6 TON MULLER SIEPPARD (E)
INFO V SKOVHOLT (L)
NOVAK DICKER SMITH (L)
C. MILES P. COLLINS ROSS IQ11GHTON TEETS (L)
B. KING DENISE IPPOLITO YOUNGBLOOD WADE (E)
REG OPR TEDESCO REGAN WILLIAMS (E)
/ FILE & REGION (3)
LONG PROJECT LDR WILSON (L)
MORRIS LAINAS STEELE BEHAR0YA HARLESS VOLI1tER EXTERUAL DISTRIBUTION LN
./1 - LOCAL PDR Sacremento. Cal.
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(1)(2)(10)-NATIONAL LAB'S V l-PDR-S AN/00dexR 1 - NSIC(BUCHANAN) 1-ASLBP(E/W Bldg,Rm 529) 1-GERALD LELLOUCIE 1 - ASLB(YORE /SAYRE/
1-W. PENNINGTON, Rm E-201 GT BROOKILWEN NAT. LAB WOODARD/"H" ST.
1-CONSULTANT'S 1-AGMED(Ruth Gussman) p46 - CYS ACRS Magggg SENT TO LIC ASST.
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SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 S Street, Box 15830, Sacramento, California 95813; (916) 452-3211
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S January 21, 1974 d
00CKr(ED USAEC O'
Mr. R. C. DeYoung
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Assistant Director for
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AEC Docket No. 5 -
g Rancho Seco Nuclear Generating 9
Station, Unit No. 1 g
Dear Mr. DeYoung:
Your letter of December 5,1973 requested that we advise you of our plans for making snubber seal modifications on Bergen-Paterson hydraulic snubbers and our proposed revisions to our Technical Specifications to provide surveillance of all snubbers installed on safety related systems.
We have completed a detailed survey of all Bergen-Paterson snubbers at Rancho Seco and the following summary can be given:
1.
Snubbers on safety related systems 98 2.
Snubbers on non-safety related systems 18 3.
Snubbers showing signs of leakage 13 We are presently in the process of reworking all of the snubbers to be installed in the containment building. This reworking will include replacement of all seal material with ethylene-propylene material.
The units will be refilled with General Electric Type SF-ll54 silicone fluid.
The testing that has been conducted to date indicates that of the various options available, these materials offer the highest level of integrity available under operating conditions. Due to the nature of seal materials, and the effect of environmental conditions on them, their exact useful service life is not known; however, preliminary testing indicates it may approach plant life or 40 years.
All Bergen-Paterson suppressors outside the containment will be reworked to include unadulterated polyurethane seals and General Electric Type 96 or 1154 silicone fluid. The various tests which have been conducted to date and previous operating experience all indicate that the failure of the polyurethane seals can be attributed to high W7 Ah ELECTRIC SYSTEM SERVING MORE THAN 600.000 IN THE H.E A R I 0F C A LLLILfLb l A l
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Mr.,R.:C. DeYoung _ January 21, 1974 operating' temperatures and humidity conditions such as are present in the dry well of BWIus. All of the snubbers installed outside the containment will be exposed to normal atmospheric temperatures '.ad humidities.
We, 3
therefore, consider this seal material and the hylraulic fluid to be acceptable for the operating environment outso'.a the containment building.
In addition. to the Bergen-Paterson snubbers, we have 57 units manufactured by the Grinnel Company of which 16 are located on safety related systems.
Of this total, eight are showing evidence of leakage.
Seven of the leaking units are located on the main steam piping systems and one is on a-high pressure injection pump suction line.
The repair work on these snubbers has not been completed at this time, but will be handled in a manner similar to the Bergen-Paterson snubbers and a final report submitted when the work has been performed.
To accommodate the uncertainty that exists regar ing the seal materials, we propose to add the following to the Surveillance Standards portion of the Technical Specifications:
1 4.14 Safety Systems Hydraulic Snubbers:
Applicability:
Applies to all hydraulic snubbers installed on safety related systems.
Objective:
To verify that the hydraulic snubbers will perform their design function.
Specification:
1.
During the first refueling interval, all hydraulic snubbers on safety related systems shall be inspected for-proper reservoir oil level and evidence of oil leakage. Any units showing evidence of oil leakage shall be disassembled and cause of leakage determined.
If the cause is determined to be seal degradation, all units exposed to a similar or harsher atmosphere shall be disassembled and seals and fluid replaced in accordance with the manufacturer's instructions.
2.
After the fifth year of ' operation, at least one unit containing ethelene propylene seals and one unit containing polyurethane seals, which are exposed to the most adverse environment (radiation and temperature),
shall be disassembled and seal material physical properties evaluated. If physical properties noted indicate seals are approaching end of useful life, as recommended by snubber f
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Mr.,R. C. DeYoung January 21, 1974
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manufacturer, all seals in units in a similar atmosphere shall be replaced not later than the next refueling interval.
In addition, if seal replacement is necessary, per above requirements, sample units from areas having less harsh environment shall be disassembled and need for seal replacement determined.
3.-
If current test programs or operating experience proves that the continuation of this inspection
- program is not required, this section of the Technical Specifications (4.14) will be deleted.
Justification for this action will be submitted to the AEC in a special report.
Basis:
The useful life of the seals and fluids being used is not now known. This surveillance program will monitor seal condition and verify ability of snubbers to perform intended design function.
This surveillance program will cover all safety related snubbers from both Bergen-Paterson and Grinnel.
If you have any questions regarding the foregoing, please contact us.
Sincerely yours,
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J. J. Mattimoe Assistant General Manager and Chief Engineer 1
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R. H. Engelken 4
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