ML20136C341

Forwards IE Circular 79-18, Proper Installation of Target Rock Safety Relief Valves. No Action Required

ML20136C341
Person / Time
Site:	Calvert Cliffs
Issue date:	09/10/1979
From:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:	Lundvall A BALTIMORE GAS & ELECTRIC CO.
References
NUDOCS 7909190367
Download: ML20136C341 (1)

Text

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, UNITED STATES

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• M O F 754UG A *1N N5v L A NI A '?4M lcc<et Ns. 50-317 50-318  !.'*113 Baltisore Gas and Electric Company A T'4: Mr. 4. E. Lundva11. Jr.

Vice President, 5ccoly P. O. Box 1475 Baltimore, Maryland 21203 Gentlew n:

The enclosed Circular No. 79-18 is forwarded to you for informatien. No written response i s required. Should you have any questions related to your understanding of the recommendations on this satter, please contact this office.

Sincerely, 1

oyce . rfer

" Of rector Enclosuras:

1. IE Circular No. 79-18

2. List of IE Circulars Issued in Last Six Months CC w/enCIs:

R. M. Douglass, Manager, Quality Assurance L. B. Russell, Cnief Engineer W. Gibson, General Supervisor, Operational QA R. C. '.. Olson, Senior Engineer K. H. Sebra, Principal Engineer l

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l ENCLOsteE 1 Accessicn No: 79C820C385 SSINS No. 6330 LMITED STATES NUCLEAR REGULATORY CCMISSICN OFFICE CF INSPECTICN .1NO ENFCRCE.wENT

'wASHINGTCN, D.C. 2C555 IE Circular No. 79-18 Cace: September 10, 1979 Page 1 of 2 PROPER IMSTALLATICN OF TARGET ROCK SAFETY-RELIEF VALVES Description of Circumstances:

As a eesult of MRC sonitoring of operating experiences involving the Target l Rock safety-relief valve, two potential problems have been identified. One potential probles is that the performance of the valve has been found to be i impaired by either excessive or insufficient insulation around the valve body when installed in its service environment. The other potential probles is that improper assembly of the sodified valve can result in inoperability of the remote air actuator.

The Target f.ock safety-relief valve is a dual purpose valve in that overpressure

! respor.se is provided by pilot valve action and automatic depressurization l (ADS) is provided by a remote air actuator. Valve operation has been found to be affected by the amount of insulation placed around the valve body. A previous IE Bulletin No. 76-06 was issued on July 21, 1976 as a result of operating experiences where excessive insulation was installed on the valve.

The excessive insulation caused excessive heat to be retained producing a higher temperature environment for the elastomeric diaphragm which resulted in accelerated deterioration of the elastomer. Failure of the elastomeric diaphrage, makes the valve inoperable in the power operation mode (i.e. manual and ADS).

Subsequently, a silicone-nonex diaphragm was developed by the manufacturer to provide a longer Iffe in high temperature environments. In addition, the IE Sulletin explicitly required that insulation be installed in accordance with the manufacturer's recommendations.

A recent licensee event report from the Monticello facility identified a potential probles resulting from insufficient insulation (i.e. just opposite of the condition addressed by IE Bulletin 76-06). During the performance of special testing of the response to safety-relief valve operation, a valve was discovered to be exceeding its design delay time for opening. Subsequent inspection and testing of the valve revealed that insufficient insulation sa cause condensatfun to accumulate in the p results in delaying the opening of the sa DUPLICATE DOCUMENT Entire document previously entered into system under:

ANo 'M 0h63% 5 No. of pages: 4

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