ML20093E690
| ML20093E690 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 09/07/1984 |
| From: | Gahm J PUBLIC SERVICE CO. OF COLORADO |
| To: | Jay Collins, Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| 24164, P-84341, NUDOCS 8410120216 | |
| Download: ML20093E690 (3) | |
Text
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4 Mr. John T. Collins Regional Administrator SEP21 r
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Suite 1000 Arlington, TX 76011 ATTN: Eric Johnson
SUBJECT:
Existing Condition on the Fort St. Vrain Refueling Floor l
Dear Mr. Johnson:
i This letter is to provide you with a description of a situation at Fort St.
Vrain that has temporarily delayed control rod drive refurbishing efforts.
This situation was ' discussed with you and Phil Wagner during a telecon on September 4,1984.
While removing a control rod drive and orifice assembly (CRDOA) from Region 7 for maintenance, a motor over-current condition on the auxiliary transfer cask (ATC) shutters occurred, preventing their full closure. Work was discontinued, and an investigation of the l
possible causes began.
The ATC shutters were opened, and an attempt to lower and reinstall the CRDOA into the core was made.
The mechanism could not be i
completely seated in the penetration, so the CRDOA was again withdrawn from the core into the ATC. 'Once this was completed, a radiation survey was performed around the ATC.
This indicated an abnormal radiation profile for a fully retracted control rod pair in the ATC, introducing the possibility that the control rod (s) were not fully retracted. The ATC shutter drive shafts were removed, and a borescope was inserted for visual examination. These examinatic :s revealed that one of the two control rod strings was not fully l
retracted.
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. A special test was conducted on Septes.ber 5,
1984, with Messrs. Chaney and Plumlee of the NRC on-site and cognizant.
This test involved lifting the ATC approximately 4 inches to ' verify borescope observations and to obtain radiation level data.
Video tape taken during'the test revealed that indeed only one control rod string was not fully retracted.
Radiation levels at the circumference of the ATC were on the order of 5 R/hr.
This corresponds to approximately 80 R/hr at one foot from the ccntrol rod string.
All CRDOA work has oeen discontinued until it is established that the CRDOA can be removed from'the reactor in accordance with Fort St.
Vrain licensing ' requirements and without causing unnecessary health hazards to plant persortne.1,s._ __.
As always, Public---Service-Company-will kiep the Nuclear Regulatory Commission abreast of the~^ existing conditions.
If you have any questions please ~ "chn' tact" Mr. Chuck Fuller, of my staff, at (303) 785-2224, extension _202.
Sincerely, h
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/J W. Gahm
,f Manager, Nuclear Production JWG/dkh
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Title:
0R Submittal: General Distribution Document Control Desk Rids Code H005 (Region copy, NRC PDR, LPDR, NSIC, NTIS) i LTR.
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LTR.
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Region IV Internal:
Recion IV External:
Region IV Supense Copy State: COLORADO P. Wagnar 7 (3)
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REGION IV ROUTING:
NRR OVERSIGHT:
R. Denise NRR/0RB3/BC: J.R. Miller 7)
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J. Collins NRR/DL/DIR:
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E. Johnson NRR/DL/0RAB
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J. Jaudon NRR/DSI/METB sI i
R. Ireland Do not Return to RIV File Room i
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