ML20037B282
| ML20037B282 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, Zion  |
| Issue date: | 07/21/1976 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Brian Lee COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8009100919 | |
| Download: ML20037B282 (1) | |
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Cb. TRAL FILES trairso sraras NUCLEAR REGULATORY COMMISSION
~T REGION lli
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729 ROOSEVfLT ROAD GLEN EL1YN, ILLINOIS 40137
[JUL' 2 1 " ' _
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Commonwealth E.11 son Company Docket Ho'. 50-10
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ATIN: Mr. Byron Lee, Jr.
Docket No. 50-237 Vice President Docket No. 50-249 M
P. O. Box 767 Docket No. 50-254
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chiraga, T114=ais 60690 Docket No. 50-265
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Docket No. 50-295 Docket No. 50-304
- o Gentlemen
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Enclosed is IE Bulletin No. 76-46 which requires action by you with regard to your power reactor facilities with an operating 14 e====.
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Should you have questions regarding this Bulletin or the actions required of you, please contact this offica.
Sinearely, James G. Kappler Rag 4==1 Director
Enclosure:
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IE Bullatin No. 76-46 IE Files Diaphragm Failure in Air Central Files Operated Anr414=ry Actuators PDR
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For Safety Ralt=f Valves Local PDR Anthony Roisman, Esq., Attorney ec w/ encl OGC, Beth, P-506A B. Stephenson, Station Superintendent 0
N. J. Kalivin4=b4s, Plant hi 7
Superintendent J. Bital, Plant Superint== dant l?
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lE Bulletin No. 76-06 Date: July 21, 1976 m -
Page 1 of 3 DIAPilRAGM FAILURES IN AIR OPERATED AUXILIARY ACTUATORS FOR l
-SAFETY / RELIEF VALVES I
DESCRIPTION OF CIRCUMSTANCES:
I On July 8,1976, Vermont Yar kee reported that during a scheduled refueling outage surveillance test on their Target Rock valves, the auxiliary air actuator was found to be inoperable on three of the four valves.
The licensee reported that investigation disclosed that the actuator diaphragms, composed of dacron fabric reinforced silicone rubber, had been-degraded by excessive heat.
The excessive heat is attributed to the fact that, contrary te the valve manufacturer's installation instructions,' thermal insulation had been applied to the pneumatic actuator. The licensee further reported that the valve in which the diaphragm was found not to be degraded, was instal]ed in the direct path of cooling air discharge from the venti-lation system, thus receiving supplementary cooling.
Elastomeric materials such as the subject diaphragms are known to have finite service life and to be degraded by excessive temperatures; however, this is the first reported instance of degradation of this componert. This event has particular safety significance, since failure of the diaphragms defeats the function of the Autom'atic Depres-surization System.
In recognition of this situation, the NRR Division of Operating Reactors conducted a telephone su,rvey on July 16, 1976, of selected BWR operating facilities.
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IE Bulletin No. 76-06 l
Date:
July 21, 1976 Page 2 of 3 ACTION T0 bE TAKEN BY LICENGEE: '
All operators of BUR and PWR reactor facilities.with operating licenses are to take the following action:
1.
Determine that the insulation installed on safety related diaphragm operated relief valves in high temperature fluid systems is in accordance with the current recommendations of the valve vendor 1.e.,
that there is no thermal insulation on the air actuator.
2.
Ensure that the procedures used for the disassembly and inspection of these valves, as required by the Technical Specifications, specifically include in-speition of the subj ect diaphragms to determine that no significant deterioration of the diaphragm material has occurred.
3.
Ensure that the vendor's recommended service life and shelf life for the diaphragms is not exceeded for the environmental conditions to which the material is exposed.
4.
A report'of your plans and schedules for accer.p-lishing the above actions should be submitted within 10 days af ter receipt of this Bulletin.
For facilities already surveyed by URR: DOR, this report shculd con-firm information reported orally.
5.
The NRC Regional Office should be promptly informed, within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, of any adverse findings resulting f rom your inspection and/or review of the subject diaphragma or their application.
6.
Within 20 da:*s after completion of the actions described in Item 4 above, repcrt the results, in-cluding f or any valves found to have degradat ion of Jiaphragms, the make, type, size, diaphragm marerial, and service (system) application.
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IE Ilulletin No. 76-06 D.ite : July 21, 1976 Page 3 of 3 y
Reports should be submitted to tlie Director of the NRC Regional Office and a copy should be forwarded to the NRC Officc of Inspection and Enforcement, Division ef Reactor inspection l'rograms, Washington, D. C.
20555.
Approval of NRC requirements for reports concerning possibic generic problems has been obtained under 44 U.S.C 3152 from the U. S. Cencral Acccunting Office.
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(GAO Approval B-180255(R0072), expires 7/31/77).
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