ML19309D382
| ML19309D382 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 02/29/1980 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| NUDOCS 8004100309 | |
| Download: ML19309D382 (3) | |
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NUCLEAR REGULATORY COMMISSION 5
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February 29, 1980 y. s.,/
Docket No. 50-213 Mr. W. G. Counsil Vice President Nuclear Engineering and Operations Connecticut Yankee Atomic Power Cogany Post Office Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
During the last several years, data have begun t1 indicate that the fission gas release rate from LWR fuel pellets is increased (enhanced) with burnup.
Many of the current fuel performance analyses do not consider the igact of burnup-enhanced release on safety.
By letters dated November 23,1976, the NRC staff requested all LWR licensees to assess the higher fission gas release for fuel burnups above 20,000 Megawatt-day per metric ton (MWD /t).
Also, by NRC staff letter dated January 18, 1978, all U. S. LWR fuel suppliers were requested to revise their fuel performance analyses to include the enhance-ment of fission gas release at higher burnups.
All responses to the November 23, 1976 letters have been reviewed. We have concluded that no immediate licensing action is required for operating reactors.
This conclusion is valid for typical reported LWR fuel bundle and batch burn-ups.
Any extension of these burnups or other factors which significantly affect fission gas release, LOCA PCT or fuel rod internal pressure is outside the scope of the conclusion.
Westinghouse was the only fuel supplier calculating that tne increased release would cause internal fuel rod pressure to exceed coolant system pressure.
The staff has approved revised design criteria which allow internal rod pressures greater than system pressure. The staff is also cogleting the review of a Westinghouse revised fuel performance code.
The staff, in evaluating reloads, has been requesting licensees using Westinghouse fuel to quantify the burnup when the newly approved design criteria will be violated.
In the reloads eval-uated thus far, there appears to be-a significant burnup margin to the newly approved evaluated design criteria to compensate for modifications which may result from the staff's review of the Westinghouse revised fuel performance code.
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2-February 29, 1980 Mr. W. G. Counsil Inasmuch as you and/or the staf f will be evaluating all future reloads against fuel vendors' revised fuel performance codes which provide for increase in fission gas release at higher burnups, we consider this a satisfactory resolution of this concern.
Sincerely, Dennis L. Ziema Chief Operating Reactors Branch #2 Division of Operating Reactors I
cc:
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9 Mr. W. G. Counsil February 29, 1980 cc Day, Berry & Howard U. S. Environmental Protection Counselors at Law Agency One Constitution Plaza Region I Office Hartford, Connecticut 06103 ATTN:
EIS C00RDINATOR JFK Federal Building Superintendent Boston, Massachusetts 02203 Haddam Neck Plant RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 Mr. James R. Himmalwright Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 Russell Library 119 Broad Street Middletown, Connectic'ut 06457 Board of Selectmen Town Hall Haddam, Connecticut 06103 Connecticut Energy Agency ATTN: Assistant Director Research and Policy Developeent Department of Planning and Energy Policy 20 Grand Street Hartford, Connecticut 06106 Director, Technical Assessment Division Office of Radiation Programs (AW-459)
U. S. Environmental Protection Agency Crystal Mall #2 Arlington, Virginia 20460 L