ML19309D383
| ML19309D383 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 02/29/1980 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| NUDOCS 8004100311 | |
| Download: ML19309D383 (3) | |
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NUCLEAR REGULATORY COMMISSION i
UNNED STATES 3,,
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WASHINGTON, D. C, 2066S Sg..... j[
February 29, 1980 Dockot No. 50-245 4
Mr. W. G. Counsil, Vice President Nuclear Engineering and Operations Northeast Nuclear Energy Company P. O. Box 270 Hartf ord, Connecticut 06101
Dear Mr. Counsil:
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 inpact of burnup-enhanced release on safety.
By letters dated Novenber 23, 1976, the NRC staff requested all LWR licensees to assess the higher fission gas release f or 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.
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 (^25,000 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 LCCS 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 insnediate licensing action is necessary on operating BWRs.
s 8 0 0 410 03H
t-Mr. W. G. Counsil February 29, 1980 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, i
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,
- M S l
Dennis L. Ziemann', Chief Operating Reactors Branch #2 o
Division of Operating Reactors cc:
See next page N
Mr. W. G. Counsil February 29, 1980 CC William H. Cuddy, Esquire Connecticut Energy Agency ATTN: Assistant Director Day, Berry & Howard Counselors at Law Research and Policy One Constitution Plaza Development Hartford, Connecticut 06103 Department.of Planning and Energy Policy Anthony Z. Roisman 20 Grand Street Natural Resources Defense Council Hartford, Connecticut 06106 91715th Street, N. W.
Washirgton, D. C.
20005 Director, Technical Assessment Division Northeast Nuclear Energy Company Office of Radiation Programs ATTit: Superintendent (AW-459)
Millstone Plant U. S. Environmental Protection P. O. Box 128 Agency Waterford, Connecticut 06385 Crystal Mall #2 Arlington, Virginia 20460 Mr. Janes R. Himmelwright Northeast Utilities service Company U. S. Environnental Protection P. O. Box 270 Agency Hartford, Connecticut _06101 Region I Office ATTN:
EIS COORDINATOR Resident Inspector JFK Federal Building c/o U. S. NRC Boston, Massachusetts 02203
. P. O. Box Drawer KK Niantic, Connecticut 06357 Waterford Public Library Rope Ferry Road, Route 156 Waterford, Connecticut 06385 First Selectman of the Town of Waterford Hall of Records 200 Boston Post Road Waterford, Connecticut 06385
.