ML19224C469
| ML19224C469 | |
| Person / Time | |
|---|---|
| Site: | Bailly |
| Issue date: | 06/20/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Shorb E NORTHERN INDIANA PUBLIC SERVICE CO. |
| References | |
| NUDOCS 7907020432 | |
| Download: ML19224C469 (1) | |
Text
[pe nr.;g*'o, UNITE D STATES E\\, q ' 'g NUCLEAR REGULATORY COMM!SSION EC g h' "'[
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g GLEN ELLYN, ILLINOls 60137 Jim 2 0 i979 Docket No. 50-367 Northern Indiana Public Service Company ATTN:
Mr. Eugene M. Shorb Senior Vice President 5265 Hohman Avenue Hammond, IN 46325 Gentlemen:
This Information Notice No. 79-17 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 actions.
If you have questions regarding this matter, please contact the Director of this office.
Sincerely, Jas:.s G. Kepp er Director
Enclosure:
IE Information Notice No. 79-17 cc w/ encl:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Mr. Dean Hansell, Office of Assistant Attorney General 271 326 790702DY3Q CP
U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III June 20, 1979 IE Information Notice No. 79-17 SOURCE HOLDER ASSEMBLY DAMAGE FROM MISFIT BETWEEN ASSEMBLY AND RF).CTOR UPPER GRID PLATE Description of Circumstances:
Recently, the NRC was informed of a problem at two Westinghouse PWR facilities resulting frcm an apparent misfit betweei secondary source holder assemblies and the reactor upper grid plate.
The misfit problem was first identified by Carolina Power & Light, licensee for H. B. Robinuon U:.it 2, who informed the NRC on May 6, 1979, of the circum-stances. During the current refueling ou* age at H. B. Robinson 2, CP&L deter-
'ad been damaged during the mined that two secondary source holder ermmL112-i previous refueling in February 1978, by a misfit between the assembly and the reactor upper grid plate. The misfit resulced from insufficient clearance (i.e. 1/2 to 3/4 inch) between the source holder assembly hub and the grid plate at the core loca: ions containing thermocouple mixing vanes. This lack of sufficient clearance caused minor deformation of the upper grid plate com-ponents at the core location and of the source holder assemblies. The deforma-tion also resulted in some bending of the fuel reds in the assembly, howeve2, in no case did this bending result in fuel claddini; perforation.
On May 16, 1979, the licensee of D. C. Cook Unit 1 informed the KRC that the present refueling outage would be extended 15 t.e '.0 days to remove the reactor head, which had already been reinstallec following completion of refueling, to correct this risfit problem. They learned of.the problem from WesHnghouse.
Subsequently, the licensee's inspection revealed that the source hcider assembly hubs were in contact with the vanes. The source holder was removed from one assembly readily with no apparent damage while in the other the source holder was found stuck in the assembly. The problem was corrected prior to return to operations.
The secondary source assembly rods are normally inserted into rod cluster control assemblies and placed at sy= metrical locations in the core. Each such assembly contains a symmetrical grouping of four secondary source rods and between zero and twenty burnable poison rods. Locations in the assembly not filbd with a source or burneF'.e poi of sufficient clearance for these so DUPLICATE DOCUMENT L[1 797 9
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only at the core locations which con Entire document previously entered into system under:
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