ML18139A039
| ML18139A039 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 02/25/1980 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Ferguson J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| NUDOCS 8003130034 | |
| Download: ML18139A039 (2) | |
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~o' Docket Nos. 50-280 and 50-281 Mr. J. H. Ferguson UNITED ST ATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 FEBRUA.J'Y 2 S 1980 Executive Vice President - Power Virginia Electric and Power Company Post Office Box 26666 Richmond, Virginia 23261
Dear Mr. Ferguson:
During the last several years, data have begun to.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 impact 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 forfuel 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 No~ember 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 the incteased 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 completing 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.
Inasmuch as you and/or the staff will be evaluating all future reloads against fuel vendor_s I revised fuel performance codes which provide for increase in fission gas release at higher burnups, we consider this a satisfactory crtbxfaebo bh aiet lbolrco.
cc:
See next page iicer~uuM~.
A. Schwencer, Chief Operating Reactors Branch #1 Division of Operating Reactors
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Mr. J. H. Ferguson Virginia Electric and Power Company cc:
Mr. Michael w. Maupin Hunton and Williams Post Office Box 1535 Richmond, Virginia 23213 Mr. w. L. Stewart, Manager P. o. Box 315 Surry, Virginia 23883 Swem Library Co 11 ege of Wi 11 i a.m and Mary Williamsburg, Virginia 23185 Donald J. Burke U. s. Nuclear Regulatory Cormiission Region II Office of Inspection and Enforcement 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 FEBRUARY 2 5 19S(j