ML20217A666
| ML20217A666 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 11/15/1990 |
| From: | Vissing G Office of Nuclear Reactor Regulation |
| To: | Mroczka E CONNECTICUT YANKEE ATOMIC POWER CO., NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| TAC-77726, NUDOCS 9011210213 | |
| Download: ML20217A666 (3) | |
Text
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UNITED STATES kC j_ -- F J.o g
NUCLEAR REGULATORY COMMISSION 1
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' WASHINGTON, D. C. 20556 k...../
l November 15, 1990
' Docket No. 50-336 Mr. Edward J. Mroczka l
Senior:Vice President l
Nuclear Engineering and Operations Connecticut Yankee Atomic Power Company u
. Northeast Nuclear Energy Company ll P. O. Boxt270 3
Hartford, Connecticut 06141-0270 J
Dear Mr. Mroczka:
]
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION CONCERNING BORAFLEX DEGRADATION c
IN MILLSTONE-2 SPENT FUEL POOL STORAGE RACKS (TAC NO. 77726) o
.We are reviewing your information submitted on the subject issued by-letter i
dated October 1, 1990.
In order to complete our review, we need information concerning the propagation of. the gaps in degraded assendlies and the i
Jeriticality analysis-ofLdegraded boraflex assemblies. Specifically, we request H
answers to the.following concerns:-
[
' l ~.
Preliminary results from the blackness tests indicate that 45 panels had a i
.. gap in-the boraflex meterial with the. largest single _ measured gap approximately 1.8 inches wide. What was the total accumulated gamma-
' radiation to tnese panelstat the' time of the blackness tests? What additional ganna dose will be accu & 'ated by the boraflex panels before-y' "N
.theLnext. blackness: testing'and what additional shrinkage (gap size) could this:. cause?
.2.
JIt-is' reported: that the.results of the CE criticality analysis confirms that the K-eff of-the. spent fuel pool is.less than 0.95 for 2.7-inch gaps j
' ' located at-the same axial. elevation.throughout Region l'for the fuel-Eassemblies enriched.to 4.5 weight percent U-235.
Since the present fuel-
. assemblies stored-in Region 1 are arranged in a two-out-of-four storage Lpattern (checkerboard), was-this the configuration assumed in the CE-7 criticality analysis?j How much margin existed between the calculated m
- K-eff and 0.957 = As a result of previous Question 1~ above, could gaps
- larger than the 2.7 inches assumed in the criticality analysis occur with
- further_ irradiation?-
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9011210213 901115 i
L,40 PDR ADOCK 05000336' P
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.1 Mr. Edward J. Mroczka Millstone Nuclear Power Station Northeast Nuclear Energy Company Unit No. 2 cc:
Gerald Garfield, Esquire R. M. Kacich, Manager Day, Berry and Howard Generation Facilities Licensing
. Counselors at Law Northeast Utilities Service Company
. City Place Post Office Box 270 i
Hartford, Connecticut 06103-3499 Hartford, Connecticut 06141-0270 W. D. Romberg, Vice President D. O. Nordquist 4
Nuclear Operations Director of Quality Services Northeast Utilities Service Company Northeast Utilities Service Company Post Office Box 270 hi,i, 6ff ice Box 270 Hartford, Connecticut 06141-0270 Hartford, Connecticut 06141-0270 Kevin McCarthy, Director Regional-Administrator
' Radiation Control Unit-Region I L
Department of Environmental Protection U. S. Nuclear Regulatory Commission K
State Office Building 475 Allendale Road h
Hartford,~ Connecticut 06106 King of Prussia, Pennsylvania 19406 Bradford S. Chase, Under Secretary First Selectmen Energy Division Town of Waterford Office of Policy and Management Hall of Records 80 Washington Street 200 Boston Post Road Hartford, Connecticut.06106 Waterford, Ccnnecticut 06385 h-S. E.'Scace, Nuclear Station Director W. J. Raymond, Resident Inspector
-Millstone Nuclear Power Station Millstone Nuclear Power Station Northeast Nuclear Energy Company c/o U. S.. Nuclear Regulatory Commission i
Post Office Box 128 Post Office Box 811
[
Waterford, Connecticut 06385 Niantic,-Connecticut 06357 J. S. Keenan, Nucie n Unit Director Charles Brinkman, Manager Millstone Unit N:,. 2 Washing ~ ton' Nuclear Operations Northeasi. Nuclear Energy Company C-E Power Systems
' Post Office Box 128 Combustion Engineering, Inc.
Waterford. Connecticut 06385' 12300 Twinbrook Pkwy E
Suite 330 Rockville, Maryland 20852
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November 15, 1990 Mr. Edward J. firoczka We request your response within 45 days from receipt of this letter.
The requirements contained in this letter affect fewer than ten respondents, f
and, therefore, is not subject to Office of lianagement and Budget review under P.L.96-511.
Sincerely, i
S Guy S. Vissing, Senior Project Manager Project Directorate 1-4 Division of Reactor Projects 1/11 Office of. Nuclear Reactor Regulation
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