ML15026A574
| ML15026A574 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 02/25/1980 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Andrea Jones CAROLINA POWER & LIGHT CO. |
| References | |
| NUDOCS 8003130039 | |
| Download: ML15026A574 (5) | |
Text
REGULATORY DOCKET FILE -COP FEBRUARY o a Docket Nos. 50-261 Mr. J. A. Jones Senior Executive Vice President Carolina Power and Light Cbmpany 336 Fayetteville Street Raleigh, North Carolina 27602
Dear Mr. Jones:
Duringqthe last several years, data havebegun to indicate that the fission gas release rate fromLWR fuel pellets is increased (enhanced) with burnup.
Many.of the current fuel performance analyses do not consider the impact of burniup-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. LWI fuel suppliers were requested to revise their fuel performance analyses to Include the enhance meint 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 burnups.
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 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 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 evaluated thus far, there appears to be significant burnup marginto the newly approved design criteria to compensate for-modifications which may result from the staff review of the Westinghouse revised fuel performance code.
The resbonses concerning Combustion Engineering (CE) and Exxon>PWR-fuel bundles demonstrated that neither was there an adverse effect on ECCS evaluations nor did the internal fuel rod pressure exceed system pressure.' Therefore, no immediate licensing action is necessary on CE or Exxon fueled PWRs.
8003130 q
SU RNAM E 0.
- DATE, NKC FORk 318 (9-76) NRCM 0240
- U.S. GOVERNMENT PRINTING o'PFICIIR 18-288 789
Mr. J..
Inasmuch as you and/or the staff -will be evaluating all.future reloads against fuel vendors" revised fuel performance coded which provide for increase in fission gas release at higher.burnups, we consider this a satisfactory resolution of'ths concern.
Sincerely, Original Signe f A. Schwencer, Chief Operating Reactors Branch #
Division of Operating Reactors cc-See next page OFis>
DOR:0
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SU N M
DATE >
NRC FORM 318 to.76)
NRCM 0240
- u.s.
VE NMEINTu PRNTINms oFFIcR:
1978 - as5
-769
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 FERUARY 4 51980 Docket Nos. 50-261 Mr. J. A. Jones Senior Executive Vice President Carolina Power and 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-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 burnups.
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 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 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 evaluated thus far, there appears to be significant burnup margin to the newly approved design criteria to compensate for modifications which may result from the staff review of the Westinghouse revised fuel performance code.
The responses concerning Combustion Engineering (CE) and Exxon PWR fuel bundles demonstrated that neither was there an adverse effect on ECCS evaluations nor did the internal fuel rod pressure exceed system pressure. Therefore, no immediate licensing action is necessary on CE or Exxon fueled PWRs.
Mr. J. A. Jones
- 2 BRUApY 5
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, A. Schwencer, Chief Operating Reactors Branch #1 Division of Operating Reactors cc:
See next page
Mr. J. A. Jones Carolina Power and Light Company FEBRUARY 5
cc: G. F. Trowbridge, Esquire Shaw, Pittman, Potts and Trowbridge 1800 M Street, N.W.
Washington, D. C. 20036 Hartsville Memorial Library Home and Fifth Avenues Hartsville, South.Carolina 29550 Michael C. Farrar, Chairman Atomic Safety and Licensing Appeal Board Panel U. S. Nuclear Regulatory Commission' Washington, D. C. 20555 Richard S. Salzman Atomic Safety and Licensing Appeal Board Panel U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Dr. W. Reed Johnson Atomic Safety and Licensing Appeal Board Panel U. S. Nuclear Regulatory Commission Washington, D. C. 20555