ML19270E958
| ML19270E958 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 12/19/1978 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Koester G KANSAS GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7901040172 | |
| Download: ML19270E958 (1) | |
Text
~
pa accg,
UNITED STATES
/
.8
,{o NUCLEAR REGULATORY COMMISSION
[
REGION IV c
5..
611 RYAN PLAZA DRIVE, SUITE 1000 2
ARLINGTON, TE XAS 76011 o.,g s,, }
December 19, 1978 In Reply Refer To:
RIV Docket No.
STN 50-482/IE Bulletin 78-14 Kansas Gas & Electric Co.
Attn: Mr. Glenn L. Koester Vice President-0perations Post Office Box 208 Wichita, Kansas 67201 Gentlemen:
The enclosed IE Bulletin 78-14 is forwarded to you for infonnation.
No written response is required.
If you desire additional infonnation regarding this matter, please contact this office.
Sincerely, fG W
7 Karl V. Seyfrit Director
Enclosures:
1.
List of IE Bulletins Issued in 1978 cc: w/ enclosures Messrs. Nicholas A. Petrick, SNUPPS D. T. McPhee, Kansas City Power and Light Company Gerald Charnoff, Shaw, Pittman, Potts & Trowbridge E. W. Creel, Kansas Gas and. Electric Company 79010 4 0 / 7 L'
UNITED STATES NUCLEAR REGULATORY COMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Bulletin No. 78-14 Date:
Decc.7,ber 19, 1978 Page 1 of 3 DETERIORATION OF CUNA-N COMPONENTS IN ASCO SOLLMOIDS Description of Circumstances:
Following a reactor scram at the Monticello Nuclear Power Station on July 27, 1978, one control rod was dctermined to have a slow scram insertion time. While measuring the average control rod scram insertion times (as required by Technical Specifications), the same control rod failed to scram.
Subsequent investigation revealed that a Buna-N disc in f he scram pilot valve solanoid core assembly had fra'ctured.
Small pieces of the Buna-N materic; wedged between the core assembly and the valve pilot body.
This prevented proper movement of the core assembly (plunger), and thus prevented the valve from properly venting control air from the scram valves.
A similar event occurred during scram testing on June 5, 1978.
On both occasions the control rod failed to scram during control rod surveillance testing.
In these instances, had a scram occurred during normal operation of the reactor, the affected rods would have inserted by action of the backup scram solenoid valves.
The reactor was placed in cold shutdown on July 28, 1978 All of the scram pilot solenoid valves and scram backup valvc_ % a disassembled and inspected.
Six additional fractured Buna-N discs dere found, all in scram pilot solenoid valves.
Northern States Power Company replaced the plunger Buna-N discs in all 242 scram pilot valves and the 2 backup scram valves.
In addition to the Monticello failures, similar events were recently reported from the Big Rock Point and Pilgrim facilities. At Big Rock Point, two failures were experienced in October while at Pilgrim one failure was found in July and two in December.
All of these failures were encountered during surveillance testing.
General Electric had previously issued Service Information Letters, SIL 128 (March 31, 1975) and SIL 128 Revision 1 (January 30,1976),
addressing the deterioration through natural aging of Buna-N components in CRD scram pilot valves.
These letters recommended that a maintenance program be adopted which replaced certain Buna-N components in scram pilot valves on a regularly scheduled basis.
However, the Buna-N discs V
M 7812260230