ML19224C446
| ML19224C446 | |
| Person / Time | |
|---|---|
| Site: | Catawba, Perkins, Cherokee  |
| Issue date: | 06/20/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Dail L DUKE POWER CO. |
| References | |
| NUDOCS 7907020379 | |
| Download: ML19224C446 (1) | |
Text
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'o UNITED ST ATES 8 *y ',, cf 't NUCLEAR REGULATORY COMMISSION
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101 MAR tETT A ST., N W., SUITE 3100 o,, f ' b' ATL ANT A. GEORGI A 30303 g...../
In Reply Refer To:
jtjg 2 01979 RII:JF0 50-413, 50-414 50-488, 50-489 50-490, 50-491 50-492, 50-493 Duke Power Company Attn:
L. C. Dail, Vice President Design Engineering P. O. Eox 33189 Charlotte, North Carolina 28242 Gentlemen:
'Ihis Information Notice is provided as a. early notification of a possibly significant matter. It is expected that recipients will review the informa-tion for possible applicability to their facilities. No specific action or response 1.a requested at this time. If further NRC evaluations so indicate, an IE Cire alar or Bulletin vill be issued to recommend or request specific licensee actions. If you have questions regarding this matter, please contact the Director of the appropriate h7,C Regional Office.
Sincerely,
~
p James P. O'Rei y Director
Enclosures:
1.
IE Information Notice No. 79-17 2.
List of Information Notices Issued in 1979 271 254 7907026379
7,___.___
t JUN 2 01979
.. Duke Power Company ce w/ encl:
D. C. Bese, Project Manager Post Office Box 223 29710 Clover, South Carolins J. T. Moore, Project Manager Post of fice Bor 422 29340-Caffmey, South Carolina 1
i 1
1 l
271 255 pI e
em UNITED STATES NUCLEAR REGULATORY Co MISSION 9FFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 June 20, 1979 IE Information Notice No. 79-17 SOURCE HOLDER ASSFG LY DA4 :. FROM MISFIT BEWEEN ASSEMBLY AND REACTOR UPPER GRID PLATE Description of Circumstances:
Recently, the N1C was infor ed of a problem at two Westinghouse IVR f acilities
. resulting from an apparent tisfit between secondary source holder asse=blies and the reactor typer grid plate.
The cisfit protle= was ff-st identified by Carolina Power & Light, licensee for H. B. Robinson Unit 2, who infor ed the NRC on May 6, 1979, of the circu=-
During the current refueling outage at H. B. Robinson 2, CP&L deter-stances.
mined that two secondary source holder assemblies had been da= aged during the previous refueling in February 1978, by a misfit between the asse=bly and the reactor upper grid plate. The misfit resulted fro = insufficient clearance (i.e. 1/2 to 3/4 inch) between the source holder asse=bly hub and the grid This lack plate at the core locations cor aining thermocouple cixing vanes.
of sufficient clearance caused minor defotr.ation of the upper grid plate com-ponents at the core location and of the source holder asse=blies. The defor=a-tion also resulted in so=e bending of the fuel rods in the asse=bly, however, in no case did this bending result in fuel cladding perforation.
on May 16, 1979, the licensee of D. C. Cook Unit 1 infor ed the NRC that the present refueling outap would be extended 15 to 20 days to re=ove the reactor head, which hs* already been reinstalled following co:pletion of rafueling, to correct this misfit proble=. They learned of the problem fro = Westinghouse.
Subsequently, the licensee's inspection revealed that the source holder asse=bly hubs were in contact with the vanes. The source holder was re=oved fron one asse=bly readily with no apparent dacage while in the other the cource holder was found stuck in the ar,sc=bly.
The proble= vas corrected prior to return to operations.
The secondary source assecbly rods are normally inserted into rod cluster contr^! assemblies and placed at sy==etrical locations in the core. Each such asse:bly contains a sy=:etrical grouping of four secondary source rods and betvcen zero and twenty burnable poison rods. Locations in the assembly not filled with a source or burnable poiso 6
of sufficient cicarance for these sour 271 2,56 DUPLICATE DOCUMENT only at the core locations which conta Entire document previously en+ered into system under:
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