ML19347C527
| ML19347C527 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 09/27/1963 |
| From: | Bryan R US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| Shared Package | |
| ML19347C526 | List: |
| References | |
| NUDOCS 8011200111 | |
| Download: ML19347C527 (2) | |
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UNITED STATES ATOMIC ENERGY COWISSION HAZ ARDS ANALYSI'S BY THE RESEARCH AND POWER REACTOR SAFETY BRANCH DIVISION OF LICENSING AND REGULATION IN THE ATTER OF YANKEE ATOMIC ELECTRIC COMPANY PROPOSED CHANGE NO. 42 DOCKET NO. S0-29 Int roduction Pursuant to the provisions of Section S0.59 of the Commission's regulations, Yankee Atomic Electric Company has requested authorization of Proposed Change No. 42 in the Technical Specifications of License s
No. DPR-3.
This Proposed Change would provide for modifications of pu the in-core instrumentation system of the Yankee reactor which would
These modifications would thereby permit Yankee to use all but two of the twenty-two flux wire positions which were originally provided in the reactor to allow a determination of the neutron flux distribution in the core during operation.
Dis cussion The twenty-two flux wire thimbles originally installed in the Yankee reactor penetrate the reactor pressure vessel head through plug adapters in two groups of eleven each.
Two of the flux wire thimbles in ene group were damaged during replacement of the pressure vessel head subsequent to the first refueling operation.
Lack o f time before the resumption of operation prevented the completion of a permanent repair, and the entire group of eleven flux wire thimbles was severed and the group capped. Yankee requested and was authorized by Change No. 29, dated September 11, 1962, and supplement thereto, dated October 9,1962, to operate their reactor with the one group capped and only one-half of the flux wire thinbles in an operable l
condition throughout Core II life.
(See our related hazards analysis of October 9,1962.)
Operation with Core II has now been completed, and the reactor
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refueling operation is presently in progress.
By Proposed Change No 42, Yankee has requested authorization to make a permanent repair in the group of eleven thimbles which were capped prior to Core II operation. The repair would restore nine of the eleven inoperative i.
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, flux wire po'sitions in the group which was capped and would provide a permanent connection for supplying inert gas to the reactor pressure vessel penetration area of this group in order to reduce the possibility of Corrosion.
At the time that the one group of penetrations was being cappad, localized thimble deterioration made it advisable to perform temporary modifications in the other group of eleven flux wire penetrations.
This permitted use of the eleven flux wires in the group during Core II life, but the modifications were such that a leak in any one of the eleven thimbles in the group would have probably resulted in at least a tempor-ary shutdown of the plant. Yankee is proposing that this group be repaired in a similar manner to that in which the other group will be repaired, except that all of the eleven flux wire positions will remain in an oper-able condition.
We have reviewed the information submitted in Yankee's request and believe that the proposed modifications are adequately designed and will not jeopardize the integrity of the primary system. The use of twenty of the twenty-two flux wire positions should permit sufficient informa-tion to be obtained regarding the neutron flux distribution in the core during reactor operation to operate safely.
Accordingly, it is our b
opinion that the Proposed Change should be authorized.
Conclusion We have concluded that Proposed Change No. 42 does not present significant hazards considerations not described or inplicit in the ha:ards sunmary report, and that there is reasonable assurance that the health and safety of the public will not be endangered.
Original digried by Rctert H. Biga Robert H. Bryan, Chief Research 6 Power Reactor Safety Branch Division of Licensing 6 Regulation Date:
SEP 2 71963 e
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