Information Notice 1986-72, Failure 17-07 Ph Stainless Steel Springs in Valcor Valves Due to Hydrogen Embrittlement

Failure 17-07 Ph Stainless Steel Springs in Valcor Valves Due to Hydrogen Embrittlement

ML031250113
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill
Issue date:	08/19/1986
From:	Jordan E NRC/IE
To:
References
IN-86-072, NUDOCS 8608150013
Download: ML031250113 (3)

SSINS No.: 6835 IN 86-72 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 August 19, 1986 IE INFORMATION NOTICE NO. 86-72: FAILURE 17-7 PH STAINLESS STEEL SPRINGS IN

VALCOR VALVES DUE TO HYDROGEN EMBRITTLEMENT

Addressees

All nuclear power reactor facilities holding an operating license or a

construction permit.

Purpose

This notice is provided to inform recipients of a potentially significant safety

problem that could result from the failure of springs in solenoid globe valves

manufactured by Valcor Engineering Corporation. According to the valve manu- facturer these valve springs may fail when exposed to high temperature reactor

coolant containing hydrogen.

It is expected that recipients will review the information for applicability

to their. facilities and consider action, as appropriate, to preclude a similar

problem from occurring at their facility. However, suggestions contained in

this information notice do not constitute NRC requirements; therefore, no spe- cific action or written response is required.

Description of Circumstances

Difficulties were experienced with the operability of two solenoid-operated

globe valves (Model V526-6190A, p/n 454660001) in the charging system at the

Fort Calhoun Station, Unit 1 in August 1985. When shut, the valves could not

be reopened without securing all charging pumps. During a refueling outage in

January 1986, the two valves were disassembled and examined to determine the

cause of the valve malfunction. It was found that disc guide assembly springs

in both valves had undergone complete and catastrophic failure. The springs, which initially had 25 coils, were found in sections of only 1-2 coils. Metal- lurgical analysis of the failed springs attributed the probable cause of failure

was due to hydrogen embrittlement. The spring is made of 17-7 PH stainless steel.

Discussion with the valve manufacturer, Valcor Engineering Corporation, revealed

that during 1982-83 one failure occurred at Prairie Island Nuclear Generating

Station and two failures occurred at North Anna Nuclear Generating Station.

These spring failures were also attributed to hydrogen embrittlement.

8608150013

IN 86-72 August 19, 1986 Discussion:

Based on analysis and evaluation of the earlier spring failures, the valve

manufacturer issued a letter in 1983 to affected licensees requesting informa- tion on valve application and advised customers of a potential spring problem.

Elgiloy springs were offered on receipt of information confirming use with

reactor chemistry fluid or specific customer request. With the occurrence of

the third similar event, the valve manufacturer is planning to issue a second

letter to affected licensees conservatively recommending that valves with spring

material of 17-7 PH stainless steel used in borated water or reactor chemistry

water be closely monitored and evaluated for any change in normal operation such

as increased seat leakage or an increase in the time required to change position.

These conditions could be attributed to broken springs. The manufacturer has

concluded that hydrogen embrittlement of stainless steel springs is a complex

function of high temperature, water chemistry, water flow condition, and time of

exposure to the service condition. Therefore, all such springs made of 17-7 PH

stainless steel used in Valcor valves in nuclear power plant may be susceptible

to this failure mode under these conditions and should be considered for

replacement.

The above described events are an indication of potential licensee/vendor

interface problem. Based on the information received by the NRC, the vendor

was not completely informed via the purchase specifications regarding the service

condition to which the valve would be exposed. Further, all users of Valcor

valves were not notified of the initial problem through either oversight by the

vendor or as a result of the valves being supplied through an intermediate source.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate regional office or this office.

"dward LU Jordan, Director

Divi io$ of Emergency Preparedness

ani ngineering Response

Office of Inspection and Enforcement

L. D. Vaughan, IE

(301) 492-8811 Attachment: List of Recently Issued IE Information Notices

Attachment 1 IN 86-72 August 19, 1986 LIS OF RECENrLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

86-71 Recent Identified Problems 8/19/86 All power reactor

With Limitorque Motor facilities holding

Operators an OL or CP

86-70 Spurious System Isolation 8/18/86 All GE BWR facilities

- Caused By The Panalarm Model holding an OL or CP

86 Thermocouple Monitor

86-69 Scram Solenoid Pilot Valve 8/18/86 All BWR facilities

(SSPV) Rebuild Kit Problems holding an OL or CP

86-68 Stuck Control Rod 8/15/86 All BWR facilities

holding an OL or CP

86-67 Portable Moisture/Density 8/15/86 All NRC licensees

Gauges: Recent Incidents And authorized to possess, Common Violations Of Require- use, transport, and

ments For Use, Transportation, store sealed sources

And Storage

86-66 Potential For Failure Of 8/15/86 All power reactor

Replacement AC Coils Supplied facilities holding

By The Westinghouse Electric an OL or CP

Corporation For Use In Class

lE Motor Starters And

Contractors

86-65 Malfunctions Of ITT Barton 8/14/86 All power reactor

Model 580 Series Switches facilities holding

During Requalification Testing an OL or CP

86-64 Deficiencies In Upgrade 8/14/86 All power reactor

Programs For Plant Emergency facilities holding

Operating Procedures an OL or CP

86-63 Loss Of Safety Injection 8/6/86 All PWR facilities

Capability holding an OL or CP

86-62 Potential Problems In West- 7/3Ž186 All power reactor

inghouse Molded Case Circuit facilities holding

Breakers Equipped With A an OL or CP

Shunt Trip

OL = Operating License

CP = Construction Permit