ML19224C476
| ML19224C476 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 06/20/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Burstein S WISCONSIN ELECTRIC POWER CO. |
| References | |
| NUDOCS 7907020440 | |
| Download: ML19224C476 (1) | |
Text
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GLEN ELLYN, ILLINOIS 60137 JUN 2 01979 Docket No. 50-266 Docket No. 50-301 Wisconsin Electric Power Company ATIN:
Mr. Sol Burstein Executive Vice President Power Plants 231 West Michigan Milwaukee, WI 53201 Gentlemen:
This Information Notice No. 79-17 is provided as an early notification of a possibly significant matter.
It is expected tLat recipients will review the information for possible applicability to their facilities.
No specific action or response is requested at this time.
If further NF.C evalua; ions 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, CL-eh $1gy dames G. Keppler Director
Enclosure:
IE Information Notice No. 9 - 17 cc w/ encl:
Mr. G. A. Reed, Plant Manager Central Files Director, NRR/DPM Director, NRR/ DOR C. M. Tremmel, ORB /NRR PDR Local PDR NSIC TIC Sandra A. Bast, Lakeshore Citizens for Safe Snergy 271 338 790702 0 /Yd
U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III June 20, 1979 IE Information Jotice No. 79-17 SOURCE HOLDER ASSEMBLY Ei AGE FROM MISFIT BETWEEN ASSEMBLY AND REACTOR UPPER GRID PLATE Description of Circumstances:
Recently, the NRC was informed of a problem at two Westinghouse PWR facilities resulting from an apparent misfit between secondary source holder assemblies and the reactor upper grid plate.
The misfit problem was first identified by Carolina Power & Light, licensee for H. B. Robinson Unit 2, who informed the NRC on May 6,1979, of the circum-stances. During the current refueling outage at H. B. Robinson 2, CP&L deter-mined that tra secondary source holder assemblies had been damaged during the previous refueling i-February 1978. by a misfit between the assembly and the reactor upper grid plate. The misfit resulted from insufficient clearance (i.e. 1/2 to 3/4 inch) between the source holder assembly hub and the grid plate at the core locations 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 rods in the assembly, however, in no ecse did this bending result in fuel cladding perforation.
On May 16, 1979, the licensee of D. C. Cook Unit 1 informed the NRC that the present refueling outage would be extended 15 to 20 days to remove the reactor head, which had already been reinstalled following completion of refueling, to correct this misfit problem. They learned of.the problem from Westinghouse.
Subsequently, the licensee's inspection revealed that the source holder assembly hubs were in contact with the vanes. The source holder was removed from one assembly readily with no apparent damage while in the ;ther 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 con? ol assemblies and placed at sycsetrical locations in the core Each such asse. aly contains a syc=etrical grouping of four secondary source rods and between zero and twenty buenable poison rods. I scations in the assembly not N 1M fiAledwithasourceorburnablepoisonrodcontainathimpeolue.
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of sufficient clearance for these so * - ~
only at the core locations which con DUPLICATE DOCUMENT 2/1 339 Entire document previously entered into system undere ANO No. of pages:
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