Information Notice 1986-78, Scram Solenoid Pilot Valve (SSPV) Rebuild Kit Problems

Scram Solenoid Pilot Valve (SSPV) Rebuild Kit Problems

ML031250202
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, 05000299, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill
Issue date:	09/02/1986
From:	Jordan E NRC/IE
To:
References
IN-86-078, NUDOCS 8608270353
Download: ML031250202 (3)

SSINS No.: 6835 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 September 2, 1986 IE-INFORMATION NOTICE NO. 86-78: SCRAM SOLENOID PILOT VALVE (SSPV) REBUILD

KIT PROBLEMS

Addressees

All boiling water reactor facilities holding an operating license or a

construction permit.

Purpose

This notice is to alert recipients of a potential problem with kits used to

refurbish the scram solenoid pilot valves. Recipients are expected to review

the information for applicability to their facilities and consider actions, if

appropriate, to preclude similar problems occurring at their facilities.

However, suggestions contained in this information notice do not constitute NRC

requirements; therefore, no specific action or written response is required.

Description of Circumstances

On June 14, 1986, Vermont Yankee nuclear power plant reported that one control

rod failed to scram and five others hesitated a few seconds before scramming

during a single-rod scram time test. During the outage that preceded the scram

time test, all of the scram solenoid pilot valves had been rebuilt with

replacement kits supplied by General Electric Company (GE). The reactor had

been taken critical to perform shutdown margin tests using the in-sequence

critical method before the testing that identified the problem with the scram

solenoid pilot valves.

Three types of problems were identified in the scram solenoid valves (SSPVs)

which operated six control rods. In the one SSPV associated with the failure

to scram, the core spring of the SSPV was separated from the core assembly. On

another SSPV, the diaphragm was installed backwards on the exhaust side of the

solenoid valve. On the remaining four SSPVs, an incorrect core assembly, provided with the kits, was installed in the valve. The latter two types of

problems were associated with delayed scram initiation. Subsequent inspection

of the remaining SSPVs revealed two other types of discrepancies. These were

(1) out-of-round inside diameter of the solenoid base subassembly and (2) a

deformed spring. Although these two discrepancies did not cause abnormal scram

performance in this case, they could have had an adverse effect on scram

performance.

IN 86-78 August , 1986 Discussion:

These problems would likely delay but not prevent rod insertion during normal

operation because backup scram valves would depressurize the air header and

cause the control rods to insert.

The defective rebuild kits are used at BWR-2s, 3s, and most 4s and 5s. Vermont

Yankee used replacement kits (ASCO type 204-139) to refurbish the scram

solenoids in the Hydraulic Control Units (HCU). GE purchased 3000 of these

replacement kits from Automatic Switch Company (ASCO), the manufacturer of the

solenoid valves. GE purchased these kits as non-safety-related items and sold

them as nuclear grade. Each kit contains 11 components, of which two are

assemblies. The two assemblies are the core assembly (ASCO part 65-716-2A) and

the solenoid base sub-assembly (ASCO part 44-869-23).

On June 26, 1986, subsequent to the event at Vermont Yankee, GE returned to

ASCO 200 replacement kits (ASCO type 204-139) from their stock and requested

ASCO to perform critical inspections. ASCO inspected the two assemblies in

each kit and rejected 127 core assemblies and two solenoid base assemblies for

out of tolerance conditions. The rejected parts were replaced with acceptable

assemblies.

Although the extent of the distribution of the parts kits used to rebuild the

scram solenoid valves is not known at this time, preliminary information

suggests that these kits may be in wide distribution. GE issued Rapid

Information Communication Services Information Letter (RICSIL) No. 008 on June

27, 1986 and SIL No. 441 on July 17, 1986 regarding these problems with the

rebuild kits. GE has advised all affected utilities to return spare rebuild

kits for reinspection.

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

If you have questions about this matter, please contact the Regional Adminis- trator of the appropriate NRC regional office or this office.

r4 Jordan, Director

Divisi of Emergency Preparedness

and Engineering Response

Office of Inspection and Enforcement

Technical Contacts: Eric Weiss, IE

(301) 492-9005 K. R. Naidu, IE

(301) 492-4179 Attachment: List of Recently Issued IE Information Notices

Attachment 1 IN 86-78 September 2, 1986 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

86-77 Computer Program Error Report 8/28/86 All power reactor

Handling facilities holding

an OL or CP and

nuclear fuel man- ufacturing facilities

86-76 Problems Noted In Control 8/28/86 All power reactor

Room Emergency Ventilation facilities holding

Systems an OL or CP

86-75 Incorrect Maintenance 8/21/86 All power reactor

Procedure On Traversing facilities holding

Incore Probe Lines an OL or CP

86-74 Reduction Of Reactor Coolant 8/20/86 All BWR facilities

Inventory Because Of Misalign- holding an OL or CP

ment Of RHR Valves

86-73 Recent Emergency Diesel 8/20/86 All power reactor

Generator Problems facilities holding

an OL or CP

86-72 Failure 17-7 PH Stainless 8/19/86 All power reactor

Steel Springs In Valcor facilities holding

Valves Due to Hydrogen an OL or CP

Embrittlement

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

EL = Operating License

CP = Construction Permit