ML19330C092
| ML19330C092 | |
| Person / Time | |
|---|---|
| Site: | Sterling |
| Issue date: | 07/23/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Arthur J ROCHESTER GAS & ELECTRIC CORP. |
| References | |
| NUDOCS 8008070541 | |
| Download: ML19330C092 (1) | |
Text
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UNITED STATES j'
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KING OF PRUSSIA, PENNSYLVANIA 19406 July 23, 1980 0:cket No. 50-485 i
Rochester Gas and Electric Corporation ATTN:
Mr. J. E. Arthur Chief Engineer 89 East Avenue Rochester, New York 14649 i
Gentlemen:
The enclosed IE Circular No. 80-17, " Fuel Pin Damage Due to Water Jet from Baffle Plate Corner," is forwarded to you for information.
No written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely,
/& h..
Boyce H. Grier irector
Enclosures:
1.
IE Circular No. 80-17 2.
List of Recently Issued IE Circulars CONTACT:
D. L. Caphton (215-337-5266) l cc w/encls:
C. R. Anderson, Manager, QA Lex K. Larson, Esquire i
N. A. Petrick, Executive Director, SNUPPS Gerald Charnoff, Esquire 1
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4 ENCLOSURE 1 SSINS #6830 Accession No. g a UNITED STATES 8005050065 r 7-NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 July 23, 1980 IE Circular No. 80-17 Page 1_of 2 FUEL PIN DAMAGE DUE TO WATER JET FROM BAFFLE PLATE CORNER Description of Circumstances:
On May 8, 1980, Portland General Electric submitted a Licensee Event Report No. 344/80-06, concerning the April, 1980 discovery of failure of 0 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 cere 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 fuel pin failures involved bypass flow through gaps in the inside corner of the baffle (the fuel " sees" a l
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 were 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 assemblies which had been associated with center injection points (the fuel " sees" a 270 angle, i.e., the edge of a box as seen from outside the box),
In addition in all three, the core suppart 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 entire joint with a i
" flat land" 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 (" jetting") 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
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IE Circular No. 8C-17 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:
4 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 "as installed" core baffle may have plant specific features which could contribute to similar failures.
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.
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~IE Circular No. 80-17 July 23, 1980 RECENTLY ISSUED IE CIRCULARS Circular Subject Date of Issued to No.
Issue 80-16 Operational Deficiencies In 6/27/80 All holders of a power Rosemount Model 510DU Trip reactor OL or CP Units and Model 1152 Pressure Transmitters 80-15 Loss of Reactor Coolant Pump 6/20/80 All holders of a power Cooling and Natural Circula-reactor OL or CP tion Cooldown 80-14 Radioactive Contamination of 6/24/80 All holders of a power Plant Demineralized Water or research reactor System and Resultant Internal OL or CP, and fuel cycle Contamination of Personnel licensees 80-13 Grid Strap Damage 11 5/18/80 All holders of a power Westinghouse Fuel Assemblies reactor OL or CP 80-12 Valve-Shaft-To-Actuator Key 5/14/80 All holders of a power May Fall Out of Place When reactor OL or CP Mounted Below Horizontal Axis 80-11 Emergency Diesel Generator 5/13/80 All holders of a power Lube Oil Cooler Failures reactor OL or CP 80-10 Failure to Maintain 4/29/80 All holders of a power Environmental Qualification reactor OL or CP of Equipment 80-09 Problems With Plant Internal 4/28/80 All holders of a power Communications-Systems reactor OL or CP-80-08 BWR Technical Specification 4/ 18/80 All holders of a General Inconsistency - RPS Response Electric BWR power reactor Time OL 80-07
' Problems'with HPCI Turbine 4/3/80 All holders of a power Oil System reactor OL or CP 80-06
. Control and Accovatability 4/14/80 Medical licensees in Systems for Implant Therapy-Categories G and G1 3
Sources 30-05 Emergency Diesel-Generator 4/1/80 All holders of a power
' Lubricating 011 Addition and reactor OL or CP Onsite Supply
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