ML19309D371
| ML19309D371 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/29/1980 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | Peoples D COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8004100302 | |
| Download: ML19309D371 (3) | |
Text
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February 29, 1980 Docket Nos. 50-10/237 Mr. D. Louis Peoples Director of Nuclear Licensing Connonwealth Edison Company Post Office Box 767 Chicago, Illinois 60690 Ocar Mr. Peoples:
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 irrpact 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 innediate licensing action is required for operating reactors.
This conclusion is valid for typical reported LWR fuel bundle and batch burn-Any extension of these burnups or other factors which significantly affect ups.
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 operational restric-tions and physical limitations, the LOCA analysis is not limiting in high burn-up fuel (625,000 MWD /t). High burnup fuel generally cannot achieve linear power densities near the LOCA limit for a typical BWR operating conditions. Typically, BWRs are LOCA limited early in cycle. The limiting fuel bundle is usually in its second cycle of reactor operations where burnup levels are below "20,000 MWD /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.
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1, Mr. D. Louis Peoples February 29, 1980, Inasnuch 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 sati:; factory resolution of this concern.
Sincerely,
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Dennis L. Ziemanni Chief Operating Reactors Branch #2 Division of Operating Reactors cc:
See next page
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Mr. D. Louis Peoples February 29, 1980 CC Isham, Lincoln & Beale Departm.at of Public Health Counselors at Law ATTN: Chief, Division of One first National Plaza, 42nd floor Nuclear Safety Chicago, Illinois 60603 535 West Jefferson Springfield, Illinois 62761 Mr. B. B. Stephenson Plant Superintendent Director, Technical Assessment Dresden Nuclear Power Station Division Rural Route #1 Office of Radiation Programs Morris, Illinois 60450
( AW-459)
U. S. Environmental Protection Anthony Z. Roisman Agency Natural Resources Defense Council Crystal Mall #2 917 15th Street, N. W.
Arlington, Virginia 20460 i
Washington, D. C.
20005 U. S. Environmental Protection U. S. Nuclear Regulatory Commissien Agency ATTN:
Jinny L. Barker Federal Activities Branch P. O. Box 706 Region V Office Morris, Illinois 604,50 ATTN:
EIS C0ORDINATOR 230 South Dearborn Street Susan N. Sekuler Chicago, Illinois 60604 Assistant Attorney General Environmental Control Division 188 W. Randolph Street Suite 2315 Chicago, Illinois 60601 Morris Public Library 604 Liberty Street j
Morris, Illinois 60451 i
Chairman Board of Supervisors of Grundy County Grundy County Courthouse Morris, Illinois 60450 e
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