ML18219D968
| ML18219D968 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 02/08/1977 |
| From: | Tillinghast J Indiana Michigan Power Co, (Formerly Indiana & Michigan Power Co) |
| To: | Rusche B Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18219D968 (8) | |
Text
U.S. NUCLEAR REGULATORY <
MMISSION NRC DISTRIBUTION FoR PART 50 DOCKET MATERIAL t'RC FoRM 195 (238)
F"ace'ndiana
& Mfchi~an pan Co New York, NY J Tillinghast
.Xr B C-Rusche QfLETTER NOR IG INAL
<<WICOPY
,C3NOTORIZED fi!KJNCLASSIFIED PROP INPUT FORM DESCRIPTION ENCLOSURE Ltr per NRC request....furnishing info concerning inspection Df the broken rod control cluster assembly R-43.......
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3p PLANT NAME:
Cook /El SAFETY FOR ACTION/INFORMATION ASSIGNED AD:
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PROJECT MANAGER CT MANA E
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ISTRl BUTION INTERNALD SYSTEMS SAFETY PLANT SYSTEMS NRC PDR HEINEMAN
, SCHROEDER TEDESCO OELD GOSSICK & STAFF ENGINEERING IPPOL TO MIPC MACARRY KNIGHT.
CASE OPERATING REACTORS SIHWEIL STELLO HARLESS PAWL CK OPERATING TECH+
REACTOR SAFE PROJECT MANAGEMENT EISENHUT ROSS NOVAK ROSZTOCZY BOYD P
COLLINS HOUSTON PETERSON MELTZ CHECK B
E HELTEMES SKOVHOLT AT& I SALTZMAN RUTBERG EXTERNALDISTRIBUTION LPDR TIC:
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NAT LAB a
ULR KSON OR ASLB:
CON ULTANTS:
ACRS CYS RIeRDXSG/
E T NRC FORM 198 {2.78)
DOCKET NUMBER Se-FILE NUMBER DATE OF DOCUMENT 2"8-77 DATE RECEIVED 2-11-77 NUMBER OF COPIES RECEIVED
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ERNST BALLARD SPANGLER SITE TECH GAMMILL STEPP HULMAN SITE ANALYSIS VOLLMER BUNCH J ~ COLLINS KREGER CONTROL NUMBER 19/
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INDIANA S MICHIGAN POWER COMPANY P. 0. BOX 18 BOWLING GREEN STATION NEW YORK, N. Y. 10004 February 8, 1977 Donald C. Cook Nuclear Plant Docket, No. 50-315 cy DPR No.
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Dear Mr. Rusche:
This letter is submitted in response to your request, to be kept informed of the status of our inspection of the broken rod control cluster assembly R-43.
After the shutdown of Unit No.
1 of the Donald C.
Cook Nuclear Plant on December 23, 1976 for its first refueling, hot rod drop timing tests were performed on each control rod.
The purpose of these tests was to verify that each of the control rods operated properly and were capable of performing their design function.
The tests were performed on December 24, 1976 and the results showed that all rod drop times were within the technical specification requirements.
In particular, the R-43 drive line drop traces exhibited a typical trace
- shape, indicating a free drive line.
Prior to any fuel movement an underwater television camera was lowered over the core to view the area in core location E-3 where the broken control rod was located.
The investigation revealed that one vane had completely separated from the rod control cluster assembly hub.
The vane contained two rodlets which were fully inserted in fuel assembly A-33.
There were no indications of debris or mechanical deformation which would have prevented normal handling of the fuel assembly.
The assembly was a Region 1 fuel assembly scheduled to be discharged during the refueling outage.
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0 Mr. Benard C. Rusche The assembly containing the broken control rod was the first assembly removed from the reactor core. It was placed in the fuel transfer system upender and again 'viewed by an underwater television camera.
In this position the top of the fuel assembly and contxol rod were visually accessible over 360 degrees.
The examination revealed that the assembly could be lowered and removed to the spent fuel pit for a more detailed inspection.
The fuel assembly con-taining the control rod was successfully xemoved to the spent fuel pit without incident.
The examination in the spent fuel pit. showed that. a two-rodlet. vane had separated from the hub at the vane/hub interface, indicating failure of both the tack weld and the structural braze joint.
There was no evidence of nicks, cuts, scratches or dents to indicate that failure was due to a blow from some other component, or any evidence of deformation to indicate load-induced failure.
Additional examinations are to be performed to attempt to determine the exact cause of failure.
In addition to the examinations of the fuel assembly top nozzle and the broken control rod discussed
- above, a
visual examination program was conducted on the E-3 control rod drive rod, the guide tube removable insert and the inside of the upper guide tube at core location E-3.
The drive rod was inspected along its entire length with attention given to the gripper latch grooves.
No significant indications or markings were detected.
The guide tube removable insert was examined with specific attention given to looking for significant abrasion indications or markings.
The insert was examined around its diameter at various locations with no indications detected.
The inside of the upper guide tube was examined by viewing the guide plates and the continuous guide portion of the guide tube assembly.
Specific attention was given to detecting bent guide plates, significant abrasion indications or markings and foreign or loose material.
None of the above were detected.
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February 8, 1977 All of the above examinations were conducted by Westinghouse personnel with assistance from the plant staff.
The video tapes were reviewed by both groups and the above represents their combined findings and conclusions.
The results of the drag test on each rod contxol clustex demonstrated that each rod was free to move and the drag forces were within acceptable limits.
The rod drop timing test results and the video tapes of the inspections discussed above are available at the plant for review by the NRC Office of Xnspection and Enforcement.
As requested in the NRC Staff's Report to the
.ACRS dated December 14,
- 1976, we will provide a report of the complete results of our findings within 60 days following startup.
Very truly yours, ZZ mam o n Til ingh Vice presid cc:
G. Charnoff R. J. Vollen R. C. Callen P.
W. Ste]cetee R. Walsh R.
W. Zurgensen Bridgman R. S. Hunter
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