ML19354E459
| ML19354E459 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 01/19/1990 |
| From: | Stephen Schultz YANKEE ATOMIC ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BYR-90-009, BYR-90-9, IEB-89-003, IEB-89-3, NUDOCS 9001310228 | |
| Download: ML19354E459 (3) | |
Text
MEE ATOMC El.ECTMC WWAW
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YANKEE S80 Main Street, Bolton, Massachusetts 0,740-1398
,v January 19, 1990 i
BYR-90-009 United States Nuclear Regulatory Commission Document Control Dest Washington, DC 20555
References:
(a) USNRC Letter to YAEC, "NRC Bulletin No. 89-03:
Potential Loss of' Required Shutdown Margin During Refueling Operations," NYR 89-343, dated November 21, 1989 (b) Yankee Nuclear Power Station Operating Procedure OP-1700,.
" Core XX Reactor Refueling and Component Inspection,"
Revision No. 14, November 1988
Subject:
Potential Loss of Required Shutdown Margin During Refueling Operations 1
Dear Sir:
i Reference (a) required all licensees to respond to the concern for i
potential loss of required shutdown margin during refueling operations by assuring that adequate shutdown margin is maintained during all refueling operations.
It was requested that this be accomplished through the following actions:
1 1.
Assure that any intermediate fuel assembly configuration (including i
control rods) intended to be used during refueling is identified and evaluated to maintain sufficient refueling boron. concentration to result in a minimum shutdown margin of approximately 5%.
2.
Assure that fuel loading procedures only allow those intermediate j
fuel assembly configurations that do not violate the allowable shutdown margin and that these procedures are strictly adhered to.
3.
Assure that the staff responsible for refueling operations is trained in the procedures recommended;in Item 2 above and i
understands the potential consequences of violating these
. l procedures. This training should include the fundamental aspects of criticality control with higher enriched fuel assemblies.
The current Yankee Nuclear Power Station Operating Procedure for reactor refueling, Reference (b), does not utilize intermediate fuel assembly positioning. No provisions are included in this procedure which address the use-of possible intermediate positioning of fuel assemblies during fuel i
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7 ted States Nuclear Regulatory Commission January 19, 1990 Page 2 m3vement.
It is our intent to revise this procedure to add a precaution which addresses the use of intermediate fuel positioning.
In addition, in the unlikely case where the intermediate positioning of a fuel assembly may be necessary, the reactivity of that assembly will be compared with the reactivity of the assembly in the final core configuration. The revised procedure will only allow a fuel assembly to be positioned in intermediate core locations that will contain fuel of equal or greater reactivity in the final core loading pattern.
The reqaired boron concentration for refueling operations at the Yankee plant provides a minimum shutdown margin of 7.5%.
This includes a 1%
calculational uncertainty and accounts for the most worthy control rod being withdrawn from the core. The shutdown margin calculation is based on the final core configuration. Thus, the minimum required shutdown margin discussed in Item 1 is clearly maintained.
Strict adherence to the fuel shuffling sequence, Attachment A of Reference (b), is required. Verification of the refueling sequence is documented by responsible party initials, date, and time after each step.
The Control Room copy of the refueling procedure has a single sign-of f ' by a licensed operator whereas the charging floor and spent fuel pit copies have two sign-offs, with at least one by a licensed operator. Any deviation from the refueling sequence is addressed by cognizant personnel using a formal procedure change review process.
The fundamental aspects of criticality control and refueling procedure are currently provided in the training for the refueling operations staff.
Training to assure that the operations staff understands the potential consequeness of violating refueling procedures will~be'provided prior to the next refueling outage scheduled for June 1990.
We trust that you find this information satisfactory.- However, should you desire further information or clarification, please feel free to contact us.
Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY Stephen P. Schultz-Vice President SPS/mma/1075u cc: USNRC Region I USNRC Resident Inspector YNPS
t, d States Nuclear Regulatory Commission
( January 19, 1990 Page 3 COMMONWEALTH OF MASSACHUSETTS)
)ss WORCESTER COUNTY
)
Then personally appeared before me, Stephen P. Schultz, who, being duly-sworn, did state that he is Vice President of Yankee Atomic Electric Company..
that he is duly authorized to execute and file the foregoing document in the-name and on the behalf of Yankee Atomic Electric Company and that the.
statements therein are true to the best of his knowledge and belief.
hwMK Robert Groce Notary Public My Consnission Expires August 29, 1991 4
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