ML20033C938
| ML20033C938 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 12/02/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| TASK-15-11, TASK-15-13, TASK-RR NUDOCS 8112040514 | |
| Download: ML20033C938 (5) | |
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4 December 2,1981 Docket No. 50-155 3frIrq h N
LS05 12-003
^m &g id r
o# a f4 Dh.%.o#g'J# (Q Mr. David P. Hofikan c
g Nuclear Licensing Ad:ntnistr tor G
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Consumers Power Company 1945 W. Parnall Road p
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Jackson, Michigan 49201 1
Dear Mr. Hoffman:
SUR. LECT: BIG ROCK POINT - SEP TOPICS XV-ll, INADVERTENT LOADING AND i
OPERATION OF A FUEL ASSEMBLY IN AN IMPROPER POSITION.AND t
XV-13, SPECTRUM OF ROD DROP ACCIDENTS By letters dated September 28, 1 981 and July 1,1981 respectively you i
submitted safety assessment reports for the above topics. The staff his reviewed these assessments and our conclusions are presented in the enclosed safety evaluation reports, which complete these topics for Big Rock Point.
i These evaluations will be a basic input to the integrated assessment for your facility. The evaluations may be revised in the future if your facility design is changed or if NRC criteria relating to these topics are modified before the integrated assessment is completed.
P Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing V
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Enclosures:
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Mr. David P. Hof fman CC Mr. Paul A. Perry, Secretary U. S. Environmental Protection Consumers Power Company Agency 212 West Michigan Avenue Federal Activities Branch Jackson, Michigan 49201 Region V Office -
ATIN:
Regional Radiation Representative Judd L. Bacon, Esquire 230 South Dearborn Street Consumers Pcwer Company Chicago,.lilinois 60604 212 West Michigan Avenue Jackson, Michigan 49201 Herbert Grossman, Esq., Chairman Atomic Safety and Licensing Board Joseph Gallo, Esquire U. S. Nuclear Regulatory Commission Isham, Lincoln & Beale Washington, D. C.
20555 1120 Connecticut Avenue Room 325 Dr. Oscar H. Paris Washington, D. C.
20036 Atomic Safety -and Licensing Board U. S. Nuclear Regulatory Commission Peter W. Steketee, Esquire.
Washington, D. C.
20555 505 Pecples Building Grand Rapids, Michigan 49503 Mr. Frederick J. Shon Atomic Safety und Licensing Board Alan S. Rosenthal, Esq., Chairman U. S. Nuclear Regulatory Commission Atomic Safety & Licensing Appeal Board Washington, D. C.
20555 U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Big Rock Point Nuclear Power Plant ATIN:
Mr. C. J. Hartman Mr. John O'Neill, II Plant Superintendent Route 2, Box 44 Charlevoix, Michigan 49720 l
Maple City, Michigan 49664 Christa-Maria Charlevoix Public Library Route 2, Box 108C 107 Clinton Street Charlevoix, Michigan 49720 Charlevoix, Michigan William J. Scanlon, Esquire Chairman 2034 Pauline Boulevard County Board of Supervisors Ann Arbor, Michigan 43103 Charlevoix County Charlevoix, Michigan 49720 Resident Inspector Big Rock Point Plant Office of the Governor (2) c/o U.S. NRC Room 1 - Capitol Building RR #3, Box 600 l
' Lansing, Michigan 48913 Charlevoix, Michigan 49720 Herbert Semmel Mr. Jim E. Mills Counsel for Christa Maria, et al.
Route 2, Box 108C Urban Law Institute Charlevoix, Michigan 49720 Antioch School of Law t
l 263316th Street, NW Washington, D. C.
20460
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Mr. David P. Hoff=rn f
6 cc Dr. John H. Buck Atcaic Safety and Licensing Appeal Board U. S. Nuclear Regulatory Connission Washington, D. C.
20555 Ms. Jo.nn Bier 204 Clinton Street Charlevoix, Michigan 49720 Thomas S. Moore Atcaic Safety and Licensing Appeal Board U. S. "uclear Regulatory Conmission Washington, D. C.
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s BIG ROCK POINT SEP TOPIC XV-ll; INADVERTENT LOADING AND OPERATION OF A FUEL ASSEMBLY IN AN IMPROPER POSITION The fuel misloading event consists of the inadvertent loading of and operation with a fuel assembly in an improper position.
Two different events are con-sidered a fuel assembly loaded into an improper core location, and a properly located but, improperly oriented (i.e., rotated by 90 or 180 degrees) assembly.
Because of the low number (84) of fuel assemblies in Big Rock Point the pro-bability of a misloading cvent is lo ier than in larger BWRs.
The licensee has evaluated the event against a criterion which precludes violation of fuel thermal limits during operation at full power with any misloading that cannot be detected by plant instrumentation.
This criterion satisfies the require-ments of Section 15.4.7 of the Standard Review Plan and is acceptable.
The latest analysis of the fuel misloading event for Big Rock was performed for Cycle 15 (1977).
It was concluded that the consequences of a misplaced bundle event are much greater than those for a misoriented bundle.
The analysis of the misload bundle event showed that a large margin exists to the fuel thernal limits for the limiting case.
As a result additional analyses of this event are not necessary, and in fact, the event is not routinely reevaluated for reloads as it is not a limiting event.
This is consistent with current practice for other boiling water reactors and is acceptable.
~
We conclude that the analysis of the fuel misloading for Big Rock Point meets current requirements for this event and is acceptable.
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SEP TOPIC XV-13 SPECTRUM 0F R0D DROP ACCIDENTS AT BIG ROCK POINT The rod drop accident in a boiling water reactor is postulated to occur as a result of a series of unlikely events - (1) a control rod becomes disconnected from its drive mechanism, (2) the disconnection is un-detected and the red is inserted to the top of the core, (3) the rod sticks in the inserted position and the drive mechanism is withdrawn, and (4) the rod becomes unstuck and falls out of the core under the influence of gravity.
In order to restrict the worth of a potential dropped rod, a withdrawal sequerice is specified.
In later boiling water reactors, a Rod Worth Minimizer, Rod Sequence Control System or both is provided to enforce the sequence.
However, for some early plants, including Big Rock Point, neither was provided. An analysis was per-fon ed by the staff (Ref.1) in which it was concluded that the proba-bility of occurrence of the accident was sufficiently small to preclude the necessity of this equipment for Big Rock Point.
An analysis of the consequences of a potential rod drop accident has been perforned for the Big Rock Point reactor by Exxon Nuclear Ccrpora-tion and is reported in Reference 2.
A bounding analysis is performed in which conservative values are used for parameters important to the event - Doppler coefficient, scram worth, rod drop speed, and peaking factors. A two-dimensional (r 2) kinetics code, XTRAN, is used which has been reviewed and approved for use in PWRs and is currer.tly being reviesed for use in EWRs.
This code is similar to that used by the staff for audit reviews of such events and we conclude that its use is acceptable for the rud drop accident in Big Rock Point.
Analyses were performed as a function of potential dropped rod worth and it is concluded that a rod worth of greater than 0.013tk/k is required to reach the acceptance criterion of 280 calories per gram for the peak fuel enthalpy.
No credit was taken for moderator feed back in this analysis. Analyses by the staff consultant, Brookhaven National Labo-ratories, repor.ed in Reference 3, show that including moderator feed back reduces the peak enthalpy by approximately a factor of two.
Analyses of potential dropped rod worths for Cycles 15,16, and 17 of the Big Rock Point reactor show that the maximm value is 0.007Ak/L resulting in a maximum fuel enthalpy of 156 calories per gram as cal-culated by the XTRAN code.
This is below the Standard Review Plan Section 15.4.9 fuel failure threshold of radially averaged fuel rod enthalpy greater than 170 cal /gm at any axial location, so no fuel failure is predicted.
We thus conclude that the analysis of the rod drop accident for Big Rock Point meets current criteria and is acceptable.
References:
1.
Safety Evaluation by the Office of tiuclear Reactor Regulation Supporting Amendment T;o. 12 to facility License No. DPR-6, Consumers Power Company Big Rock Point Plant, Docket No. 50-155, October 17, 1977.
2.
XN-NF-78-51, " Exxon Nuclear Control Rod Drop Accident Analysis for Big Rock Point," January 1979.
3.
BNL-NUREG-28109, " Thermal-Hydraulic Effects on Center Rod Drop Accidents in a Boiling Water Reactor," H:iang-Shou Cheng and David J. Diamond, July 1980.
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