ML18082A833
| ML18082A833 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 07/23/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Schneider F Public Service Enterprise Group |
| References | |
| NUDOCS 8008070557 | |
| Download: ML18082A833 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION REGION I 631 PARK AVENUE KING OF PRUSSIA, PENNSYLVANIA 19406 Docket No~ 50-272 50-311 Public Service Electric and Gas Company ATTN:
Mr. F. W. Schneider Vice President - Production 80 Park Place Newark, New Jersey 07101 Gentlemen:
July 23, 1980 The enclosed IE Circular No. 80-17, 11Fuel Pin Damage Due to Water Jet from Baffle Plate Corner, 11 is forwarded to you for information.
No-written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely,
~.,..,.....;a.. yY/. -~
Enclosures:
- 1.
IE Circular No. 80-17
- 2.
List of Recently Issued IE Circulars CONTACT:
D. L. Caphton (215-337-5266) cc w/encls:
F. P. Librizzi, General Manager - Electric Production E. N. Schwalje, Manager - Quality Assurance R. L. Mitt 1, Genera 1 Manager - Licensing and Environment H. J. Midura, Manager - Salem Generating Station
"/
ENCLOSURE 1 UNITED STATES
. NUCLEAR REGULATORY COMMISSION.
OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 July 23, 1980 SSINS #6830 Accession No.:
- 8005050065 IE Circular No. 80-17 Page 1 of 2 FUEL PIN DAMAGE DUE TO WATER JET FROM BAFFLE PLATE CORNER Oescription of Circumstances:.
On May 8, 1980, Portland G*eneral Electric submitted a Licensee Event Report No. 344/80-06, concerning the April, 1980 discovery of failure of a fuel pin in each of two assemblies during the past operating cycle.
The LER stated that each of the fuel pins was located adjacent to a joint in the core baffle, and that the failures had resulted from tube vibration resulting from water jet impingement on the fuel pin.
This general type of damage has been experienced previously.
Three damaged fuel pins were found in 1971-72 at a non-domestic power plant.
Subsequently, one failed pin was found in 1973 and again in 1975 at non-domestic plants.
In 1975, one fuel pin failed at Point Beach.
These six fu.el pin failures involved bypass flow through gaps in the inside corner of the baffle (the fuel 11sees 11 a 90° angle, i.e., the edge of a box as seen from inside the box).
The baffle joints in these plants had not been peened prior to initial core loading.
Joints were peened following discovery.of the failures, and no subsequent damage has been observed near the joints where the above failures were discovered.
More recently, in July 1979 fuel.pin damage was detected in ten fuel assemblies at the Swedish Plant, Ringhals Unit 2.
In November~ 1979 fuel pin damage was
- reported at the KO-RI Unit 1 in Korea on two fuel assemblies.
Most recently in April, 1980 fuel pin failures ~re discovered in two assemblies at the end of Cycle 2 in Trojan.
In all three of the above recent instances, the failures were encountered in assembl ie.s which had been associated with center injection points (the fuel 11sees 11 a 270° angle, i.e., the edge of a box as seen from
- outside the box).
In addition in all three, the core support structures utilized a baffle plate design with a reduced number of edge to edge bolts on adjoining baffles.
An ultimate fix of the baffle joint problem is to peen the ef')tire joint with a "flat land 11 peening technique to reduce the gap between baffle segments.
Because of scheduling concerns, this was not accomplished at Trojan during the recent outage.
Instead, PGE decided to install stainless steel pins adjacent to the two baffle joints of concern, and delay further peening efforts until the next refueling outage.
High velocity coolant cross flow (
11 jetting 11 } through the gaps of the core baffle joints can result in damage to only a very limited number (usually 1 or
- 2) fuel pins, and only at certain discrete elevations on those pins.
Since
IE Circular No. 80-17
-e*
July 23, 1980 Page 2 of 2 there is no mechanism for propagation of the failures to adjacent pins, these failures are not viewed as a significant safety concern.
However, in order to keep fuel failures and resulting primary coolant activity levels as low as possible, we recommend.the following actions.
Recommended Actions for PWR Construction Permit Holders and PWR Licensees:
- 1.
Determine core locations that might be subject to water jet impingement upon fuel pins that *could potentially be damaged by fretting.
- 2.
(Licensees only).
Examine fuel pins that were discharged from those locations, or are now at those locations (during the next refueling outage).
- 3.
Take appropriate actions to correct/prevent occurrence of this problem.
Although this problem has appeared only in certain Westinghouse PWRs, this Circular is being distributed to all PWRs since there may be other designs where the 11as installed 11 core baffle niay have plant specific features which could contribute to similar f~ilures.
No written response to this Circular is required. If you desire additional information regarding this matter, contact the Director of the appropriate NRC Regional Office.
IE Circular No. 80-17
- July 23, 1980 RECENTLY ISSUED IE CIRCULARS Circular No.
80-16 80-15 80-14 80-13 80-12 80-11 80-10 80-09 80-08 80-07 80-06 80-05 Subject Operational Deficiencies In Rosemount Model 510DU Trip Units and Model 1152 Pressure Transmitters Loss of Reactor Coolant Pump Cooling and Natural Circula-tion Cooldown Radioactive Contamination of Plant Demineralized Water System and Resultant Internal Contamination of Pe~sonnel Grid Strap Damage in Westinghouse Fuel Assemblies Valve-Shaft-To-Actuator Key May Fall Out of Place When Mounted Below Horizontal Axis Em~rgency Diesel Generator Lube Oil Cooler Failures Failure to Maintain Environmental Qualification of Equipment Problems With Plant Internal Communications* Systems BWR Technical Specification Inconsistency - RPS Response Time
'Problems with HPCI Turbine Oil System Control and Accountability Systems for Implant Therapy Sources Emergency Diesel-Generator Lubricating Oil Addition and Ons ite Supply Date of Issue 6/27/80 6/20/80 6/24/80 5/18/80 5/14/80 5/13/80 4/29/80 4/28/80 4/ 18/80 4/3/80 4/ 14/80 4/1/80 Issued to All holders of a power reactor OL or CP All holders of a power reactor OL or CP All holders of a power or research reactor OL or CP, and fuel cycle licensees All holders of a power reactor OL or CP All holders of a power reactor OL or CP All holders of a power reactor OL or CP All holders of a power reactor OL or CP All holders of a power reactor OL or CP All holders of a General Electric BWR power reactor OL All holders of a power reactor OL or CP Medical licensees in Categories G and Gl All holders of a power reactor OL or CP