ML19224C462
| ML19224C462 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 06/20/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Davidson D CLEVELAND ELECTRIC ILLUMINATING CO. |
| References | |
| NUDOCS 7907020419 | |
| Download: ML19224C462 (1) | |
Text
[pa **cq 'o UNITED STATES TIC E '? ;.,_, gi,'n NUCLEAR REGULATORY COMMISSION
$\\k'2$Q>v-E REGION 111 o,,3A S
199 ROOSEVE LT ROAD 8
GLEN ELLYN, ILLINOIS 60137
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JUN 2 01979 Docket No. 50-440 D;cket No. 50-441 The Cleveland Electric Illuminating Company ATTN:
Mr. Dalwyn R. Davidson Vice President - Engineering P. O. Box 5000 Cleveland, 011 44101 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 I2 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, WA
(/ James G. Ke p er Director
Enclosure:
IE Information Notice No. 79-17 cc w/ encl.
Central Files Director, NRR/ LPM Director, NRR/ DOR PDR Local PDR NSIC TIC liarold W. Kohn, Power Siting Commission Mr. Daniel D. Wilt, Attorney 271 310 (V
790702o97
U.S. NUCLEAR REGULATORY COMMISSION OFFICE DF INSPECTION AND ENFORCEMENT REGION III June 20, 1979 IE Information Notice No. 79-17 SOURCE HOLDER ASSEMBLY DAMAGE FROM MISFIT BETWEEN ASSEMBLY AND REACTOR UPl'ER 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 Powet & 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-eined that two secondary source holder assemblies had been damaged during the previous refueling in February 1978, by a misfit between the assembly and the reactor upper grid plate. The misfit resulted from insufficiet: clearance (i.e. 1/2 to 3/4 inch) between the source holder assembly hub a: d the grid plate at the core locations containing thermocouple mixing vanes. This lack of sufficient clearance ased 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 bendi,3 of the fuel rods in the assembly, however, in no case 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 wculd be extended 15 to 20 days to remove the reactor head, which had already been reinstalled following completion <f 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 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.ormally inserted into rod cluster control assemblies and placed at symmetr :al 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 filled with a source or burnable poison rod crow n th irkl a nie NJ4 j
of sufficient clearance for these only at the core locations which DUPLICATE DOCUMENT Entire document previou y en red into system under:
h PNO No. of pages:
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