ML19309B960
| ML19309B960 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 03/10/1980 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Jackie Jones CAROLINA POWER & LIGHT CO. |
| References | |
| NUDOCS 8004070404 | |
| Download: ML19309B960 (3) | |
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March 10, 1980
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Docket Nos. 50-325 and 50-324 Mr. J. A. Jones Executive Vice President Carolina Power & Light Company 336 Fayetteville Street Raleigh, North Carolina 27602
Dear Mr. Jones:
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 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'
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suppliers were requested to revise their fuel performance analyses to include the enhancement of fission gas release at higher burnups.
All responses to the November 23, 1976 letters have been reviewed. We have concluded that no ininediate licensing action is required for operat-ing reactors.
This conclusior is valid for typical reported LWR fuel bundle and batch burnups.
Any extension of these burnups or other fac-tors which significantly affect fission gas release, LOCA PCT or fuel rod internal pressure is outside the scope of the conclusion.
The effect of enhanced release on BWR ECCS performance has been discussed with General Electric (GE). GE has pointed out that because of opera-tional restrictions and physical limitations, the LOCA analysis is not limiting in high burnup fuel (25,000 WD/T).
High burnup fuel Generally cannot achieve linear power densities near the LOCA limit early in cycle.
The limiting fuel bundle is usually in its second cycle of reactor opera-tions where burnup levels are below ~_20,000 WD/T. Late in a BWR fuel cycle, there is less axial power peaking reducing the feasibility for any given axial location to exceed LOCA linear power density limits, and the fuel bundle power is generally limited by MCPR considerations.
- Thus, it is unlikely that a high burnup bundle can exceed the ECCS performance criteria in case of a LOCA. The argument is appropriate for Exxon fuel bundle design also based on the review of Exxon analyses for operating BWRs.
Therefore, no immediate licensing action is necessary on operating BWRs.
8004070
Inasmuch as you and/or the staff 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,
< 7..
ThomdI A. Ippolito, Chief Operating Reactors Branch #3 Division of Operating Reactors cc:
See next page 4
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Mr. J. A. Jones -
cc:
Richard E. Jones, Esquire Carolina Power & Light Company 336 Fayetteville Street Raleigh, North Carolina 27602 George F. Trowbridge, Esquire Shaw, Pittman, Potts & Trowbridge 1800 M Street, N. W.
Washington, D. C.
20036 John J. Burney, Jr., Esquire Burney, Burney, Sperry & Barefoot 110 North Fifth Avenue Wilmington, North Carolina 28401 Resident Inspector U. S. Nuclear Regulatory Commission P. O. Box 1057 Southport, North Carolina 28461 Southport - Brunswick County Library 109 W. Moore Street Southport, North Carolina 28461 Mr. Fred Tollison Plant Manager P. O. Box 458 Southport, North Carolina 28461
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