ML19323A030
| ML19323A030 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 04/04/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Martin T Public Service Enterprise Group |
| References | |
| NUDOCS 8004110071 | |
| Download: ML19323A030 (1) | |
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UNITED STATES 8
NUCLEAR REGULATORY COMMISSION o
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REGION I 631 PARK AVENUE
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H KING OF PRUSSIA, PENNSYLVANIA 19406 Docket Nos. 50-354 50-355 Public Service Electric and Gas Company ATTN.
Mr. T. J. Martin Vice President Engineering and Construction 80 Park Place Newark, New Jersey 07101 Gentlemen:
The enclosed IE Bulletin No. 80-07, "BWR Jet Pump Assembly Failure," is forwarded to you for information.
No written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, W
Boyce H. Grier M irector
Enclosures:
1.
IE Bulletin No. 80-07 with Attachments 2.
List of Recently Issued IE Bulletins CONTACT:
D. L. Caphton (215-337-5254) cc w/encls:
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E. N. Schwalje, Manager - Quality Assurance, Engineering and Construction Department 1
0084110 071;
SSINS No.:
6820 Accession No.:
UNITED STATES 8002280648 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Bulletin No. 80-07 Date: April 4, 1980 Page 1 of 4 BWR JET PUMP ASSEMBLY FAILURE i
Description of Circumstances:
On February 2, 1980, Commonwealth Edison Company (CECO) reported that a jet pump failed in Dresden Unit 3 while operating at about 67 percent of full power in a coastdown mode to a refueling shutdown. Observed changes in plant parameters during th-event indicated an individual jet pump failure had occurred.
In accordance with T.S., an orderly plant shutdown was begun to bring the unit to cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
The plant parameter changes reported by the licensee were (1) generator electrical output decreased from 539 to 511 MW electrical ~, (2) core thermal power decreased as indicated by decreased APRM readings and steam flow tg the turbine, (3) indicated total core flow increased from 97.6 to 104.7 x 10 lb./hr., (4) core plate differential pressure decreased from 16.1 to psid.,and(5)Brecirculationloopflowincreasedfrom49to54x10}3.8 gpm while A recirculation loop flow remained at 49 x 10 gpm.
These changes were readily observed by the operator in the control room and it was postulated that a jet pump had failed.
Individual jet pump readings were taken, the jet pump operability surveillance was performed, and an apparent failure of jet i
pump No. 13 was determined.
t Following vessel head removal and defueling, TV camera and visual inspections of the jet pumps and vessel annulus revealed the hold-down beam assembly of the suspect jet pump had broken across its ligament sections at the mean I
diameter of the bolt thread area. Failure of the beam assembly resulted in pump decoupling at the diffuser connection.
Subsequent insitu ultrasonic examination of all other jet pump hold-down beams, using a special UT technique developed by General Electric (GE), revealed ultrasonic indications of cracking i
at the same location in 6 of the remaining 19 beams examined.
Initial estimates of crack depth ranged from 6 to 20 mils. A sketch of the typical jet pump i
assembly is shown in Figures 1 and 2.
On March 15-16, 1980, insitu ultrasonic jet pump hold-down beam assemblies at Qu refueling).
One beam was found to contai in excess of 100 mils depth in the same 1 DUPLICATE DOCUMENT Dresden.
Entire document Previous 1y l
entered into system under:
On March 28, 1980, Boston Edison reported revea d crack indications in three (3) h p
h No. of es*
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