ML19345A439

Forwards IE Bulletin 76-06, Diaphragm Failures in Air Operated Auxiliary Actuators for Safety/Relief Valves. Action Required

ML19345A439
Person / Time
Site:	Yankee Rowe
Issue date:	07/21/1976
From:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:	Groce R YANKEE ATOMIC ELECTRIC CO.
References
NUDOCS 8011210527
Download: ML19345A439 (1)

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e July 21, 1976 Yankee Atomic Electric Company Docket No. 50-29 Attention:

Mr. Robert H. Groce Licensing Engineer 20 Turnpike Road

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k'estborough, Massachusetts 01581 Gentlenen:

t Enclosed is IE Bulletin No. 76-06 which requires action by you with f

regard to your power reactor facility (ics) with an operating license.

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Should you have questions regarding this Bulletin or the actions re-8, quired of you, please contact this office.

1 Sincerely, r

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h"A.Tnes P. O'Feilly Director

Enclosure:

IE Bulletin "o. 76-06 h

H. Autio, Plant Superintendent I

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Donald C. Allen, President t

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DATE:

July 21, 1976 Page 1 of 3 E

DIAPHRAGM FAILU?IS IN AIR OPERATED AUXILIARY ACTUATORS FOR g

SAFETY / RELIEF VALVES.

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DESCRIPTION OF CIRCUMSTANCES:

t On July 8,1976, Vermont Yankee reported that during a scheduled re-g fueling outage surveillance test on their Target Rock valves, the auxiliary air actuator was found to be inoperable on three of the four g

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valves, I's The liceNec reported that investigation disclosed that the actuator s

diaphrases, cocposed of dacron fabric reinforced silicone rubber, had Q

I been degraded by excessive heat. The excessive heat in attributed to f

the fact that, contrary to the valve manufacturer's installation in-structions, thercal insulation had.been applied to the pneumatic ac-The licensee further reported that the valve in which the tuator.

"O diaphragm was found not to be degraded, was installed in the direct path LE I

of cooling air discharge from the ventilation system, thus receiving supplementary cooling.

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t Elastoccric r.aterials such as the subject diaphragms are known to have 3

finite service life and to be degraded by excessive temperatures; 3

i however, this is the first reported instance of degradation of this f

conponent.

This evenc has particular safety significance, since failure 5

of the diaphrages defcats the function of the Automatic Depressurization T

System.

In recognition of this situation, the NRR Division of Operating

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Reactors conducted a telephone survey on July 16, 1976, of selected BWR h

operating facilit1.es.

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IE Bulletin No. 76-06 DATE:

July 21, 1976 s

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All operators of BWR and PWR reactor facilities witti operating licenses are to take the following action:

the insulation installed on safety related diaphragm f

1.

Determine that operated relief valves in high temperature fluid systets is in accordance with the current recommendations of the valve vendor, e

1.e., that there is no thermal insulation on the air actuator.

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2.

Ensure that the procedures used for the disassembly and 'nspection of these valves, as required by the Technical Specifications, 7

h specifically include inspection of the subject 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 i

for the diaphrages is not exceeded for the environmental conditions

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to which the material is exposed.

4.

A report of your plans and schedules for accomplishing the above r

actions should be submitted within 10 days af ter receipt of this Bulletin.

For facilities already surveyed by NRR: DOR, this rep, ort should confirm 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 from your inspection and/or review of the subject diaphragas or their application.

6.

Within 20 days af ter completion of the actions described in Item 4 above, report the results, including for any valves found to have degradation of diaphragms, the.make, type, size, diaphragm material, and service (system) application.

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IE Bulletin No. 76-06 DA1I: July 21, 1976 Page 3 of 3 p

Reports should be submitted to the Director of the NRC Regional Office and a copy should be forwarded to the NRd Office of Inspection and Enforcement, Division of Reactor Inspectio.. Program's, Washington, D. C.

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Approval of NRC requirements for reports concerning possible generic f

problems has been obtained under 44 U.S.C 3152 from the U. S. General b

(GAO Approval B180255(R0072), expires 7/31/77).

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