ML19309D161
| ML19309D161 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 01/25/1980 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Pilant J NEBRASKA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 8004100093 | |
| Download: ML19309D161 (1) | |
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- January 25, 1980 NSIC ek':t No. 50-298 State N:braska Public Power District ATTN:
J. M. Pilant, Director Licensing & Quality Assurance Post Office Box 499 Columbus, Nebraska 68601 Centlemen:
This IE Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the information for possible applicability to their facilities.
No specific action or response is requested at this time.
If further NRC evaluations so indicate, an IE Circular or Bulletin will be issued to recommend or request specific licensee rctions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely, 44.g* d Karl V. Seyfr Director
Enclosures:
1.
IE Information Notice No. 80-02 2.
List of Recently Issued IE Information Notices cc:
L. C. Lessor, Superintendent Cooper Nuclear Station Post Office Box 98 Brovnville, Nebraska 68321 80041000
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t SSINS: 6870 Accession No:
UNITED STATES 7912190654 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Information Notice No. 80-02 Date:
January 25, 1980 Page 1 of 2 8X8R WATER R0D LOWER END PLUG WEAR On October 3,1979, Vermont Yankee Nuclear Power Corporation (VY or Licensee) reported (LER-79-25/IP) observance of lower end plug wear on the water rods of 8X8R demonstration fuel assemblies.
These observations were obtained during refueling outage inspections.
Subsequent to the initial LER, the Licensee issued LER 79-25/IT on October 17, 1979, which provided more detailed descrip-tions of the probable cause and corrective action associated with this event.
The lower end plug wear was isolated to the water rods of the 8X8R fuel assemblies.
The cause of the wear was attributed to flow excitation of the water rods by coolant cross flow within the lower tie plate flow volume.
The repetitive contact of the Zircaloy lower end plug with the stainless steel lower tie plate resulted in prefersatial wear of the softer Zircaloy end plug.
No significant wear was observed in the lower tie plate.
To provide in-reactor experience on the modification proposed to mitigate lower end plug wear, the Licensee will include four modified 8X8R fuel bundles in their upcoming cycle of operations. The primary modification consists of using two capture water rods with shorter lower end plugs to eliminate the flow-induced excitation. Two of these fuel assemblies were previously irradiated.
The staff was. informed that VY plans to perform surveillance on these four modified bundles at the next refueling outage. The surveillance will confirm the efficacy of the modifications and the currently estimated rate of wear.
Based on evaluation of the lower end plug wear rates, and the absence of any indicated rotational movement of the water rods with worn lower end plugs, General Electric Company (GE) and the Licensee have concluded that no addi-tional corrective action is warranted at this time.
I I
To support this conclusion, on December 11, 1979, VY and GE presented detailed status of their evaluations and analysis of this condition to the NRC staff.
i As a result of the information provided in the December 11, 1979 meeting, the j
staff agreed with the conclusion that no additional corrective action is warranted at this time.
The staff requested that GE document and formally submit proprietary, and l
nonproprietary versions of their evaluations and analysis.
In addition, the i
staff requested the Licensee to submit a supplement to the earlier LER's considering the potential for loose parts.
IE Information Notice No. 80-02 Date: January 25, 1980 Page 2 of 2 To provide additional confirmatory evidence supporting the findings by GE and the Licensee, GE will develop a surveillance program specifically addressed at inspections for wear of the lower end plugs.
When this program is develoned, GE will propose the program to the NRC staff.
BWR Licensees are encouraged to participate in a surveillance program on this matter.
This Information Notice is provided as an early notification of a possibly significant matter that is still under review by the NRC staff.
It is. expected that recipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time.
If you have any questions regarding this matter please contact the Director of the appropriate NRC Regional Office.
IE Information Notice No. 80-02 January 25, 1980 LISTING OF RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 79-33 Improper Closure of 12/21/79 All power reactor Primary Containment facilities holding Access Hatches Operating Licenses (OL) and Construction Permits (cps) 79-34 Inadequate Design of 12/27/79 All holders of of Safety-Related Heat power reactor Exchangers Operating Licenses (OLs) and Con-struction Permits (cps) 79-35 Control of Maintenance 12/31/79 All power reactor facilities and Essential Equipment with an Operating Licenses (OLs) and Construction Permits (cps) 79-36 Computer Code Defect 12/31/79 All holders of power reactor Stress Analysis of Piping Operating Licenses (OLs)
Elbow and Construction Permits (cps).
79-37 Cracking in Low Pressure 12/28/79 All holders of power reactor Turbine Discs Operating Licenses (OLs) and Construction Permits (cps) 80-01 Fuel Handling Events 1/4/80 All holders of power reactor Operating Licenses (OLs) and Construction Permits (cps)
Enclosure i