ML19340A107
| ML19340A107 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 01/25/1979 |
| From: | Desiree Davis Office of Nuclear Reactor Regulation |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| TASK-04-01.A, TASK-4-1.A, TASK-RR NUDOCS 7901310171 | |
| Download: ML19340A107 (6) | |
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OAh'UARY $ q Dochet ho. 50-29
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MEliORAUDUll FOR:
D. L. Ziemann, Chief, Operating Reactors branch f 2, DDR FRO 1:
D. K. Davis, Chief, Systenatic Evaluation Program Branch, DDR
SUBJECT:
SEP N-1 SAFETY ASSESS!!E!!T It'PUT - YAt'XEE ROWE Attached is a redraf t evaluation for the following topic:
Topic IV-1.A Operation With less Than All loops In Service This evaluation is to be included in the Safety Assessment for the plant at the completion of the Systematic Evaluation Program.
!E==r Please discuss with the licensee the means by which he cesires to review this evaluation, consistent with discussions of our September 27, 1978 necting. The licensee should deterair.e either that the facts describing the plant are correct er in error.
If in error, tne correct information should be supplied. Additionally, the licensee shoulc be encouraged to supply any other material tnat night affect the staff's further use of this topic.
Odgni Sicani LF
, D;.n it Davh Don K. Davis, Chief Systematic Evaluation Program Branch Division of Operating Reactors Attachnent:
DISTRIBUTION:
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p J g WASHINGTON, D. C. 20555 e January 25, 1979 9,.....- Docket No. 50-29 ~ MEMORANDUM FOR: D. L. Ziemann, Chief, Operating Reactors Branch #2, 00R FROM: D. K. Davis, Chief, Systematic Evaluation Program Branch, D0R
SUBJECT:
SEP N-1 SAFETY ASSESSMENT INPUT - YANKEE R0WE Attached is a redraf t evaluation for the following topic: Topic IV-1.A Operation With Less Than All Loops In Service This evaluation is to be included in the Safety Assessment for the plant at the completion of the Systematic Evaluation Program. Please discuss with the licensee the means by which he desires to review this evaluation, consistent with discussions of our September 27, 1978 meeting. The licensee should detennine either that the facts describing the olant are correct or in error. If in error, the correct information should ta supplied. Additionally, the licensee should be encouraged to supply any other material that might affect the staff's further use of this topic. P e l w Don K. Davis, Chief Systematic Evaluation Program Branch Division of Operating Reactors
Attachment:
As stated cc: V. Stello D. Eisenhut P. DiBenedetto A. Burger H. Smith I r
6 SYSTEMATIC EVALVATION PROGRAM Topic IV-1.A Operation with less Than All Loops In Service Plant: Yankee Rowe Discussion The majority of the presently operating BWRs.and.PWRs are designed to permit operation with less than full reactor coolant flow. That is, if a PWR reactor coolant pump or a BWR recirculation pump becomes inoperative, the flow provided by the remaining loop or loops is sufficient for steady state operation at some definable power level, ~ usually less than full power. Plants authorized for long term operation with one reactor coolant icop out of service have submitted, and the staff has approved, the necessary ECCS, steady state and transient analysis. The remaining PWR and BWR licensees have Technical Specifications which require a reactor shut-down within 24 hours if one of the operating loops becomes inoperable and cannot be returned to operation within the time period. Evaluation The docketed material for Yankee Rowe has been reviewed with respect to operation with less than all loops in service. The search of our 1 docketed material revealed that on January 29, 1976, the licensee submitted an application for operation of the Yankee Rowe facility in the N-1 loop configuration. The application transmitted Appendix C, an analysis, entitled " Idle Loop Operation" dated January 28, 1976. The licensee requested that Appendix C be reviewed in conjunction with the information and ongoing review of proposed change number 125 entitled " Yankee Nuclear Power Station Core XII Performance Analysis", dated
July 14, 1975. However, to date, documented findings of the staff's review could not be found. The licensees' application for authorization to operate in the N-1 loop mode was the result of a loss of flow incident that occurred on January 13, 1976. The cause of the incident was determined to be an electrical fault in the motor of one of the four main coolant pumps. Repair or replacement of the pump was expected to involve significant effort and time requiring a reactor shutdown until the problem could be resolved. Therefore, the licensee submitted the N-1 loop analysis in an effort to obtain approval for 3 loop operation for an interim period with a further commitment to perform a more detailed analysis if re-sumption of 4 loop operation were not possible because of their inability to restore the inoperable pump. Yankee Rowe obtained a replacement pump from the Indian Point Unit 1 plant and resumed full flow operation within a two week period. At this time, the NRC was verbally requested by the licensee to discontinue the review of their N-1 loop submittal. In a telephone conversation with the licensee (telecon P. A. DiBenedetto, NRC, R. Groce, YAEC, January 29,1976), the fact that the application was verbally withdrawn was confirmed. Additionally, it was recognized, because of the hardware and logic modifications performed on the ECCS since tendering the N-1 loop analysis, that the submittal was no longer valid and that authorization for N-1 loop operation would have to be supported by a new analysis.
The Yankee Rowe facility is presently restricted (Technical Specifications 3.2.1 and 3.0.3) to operate with no less than all loops in service. Under Section 3/4.2, Power Distribution Limits of the Technical Speci-fications, if a Linear Heat Generation Rate (LHGR) limit is exceeded, ~ several action statements permit the licensee to operate the facility at reduced power thereby reducing the LhGR to whithin the appropriate l' nits; however, the limiting condition for operation (LCO, Technical Specification 3.2.1) is footnoted. The footnote states that operation in the 3 loop mode is not permitted until appropriate LOCA analyses =- for this mode have been approved by the NRC. This prohibits the licensee '~ from satisfying the action statements and reducing power to maintain "~~ the LHGR conducive tc that of 3 loop operation. When an action state-ment cannot be satisfied, Technical Specification 3.0.3 requires that the licensee place the facility in at least hot standby within one hour and within 30 hours be in cold shutdown unless corrective measures are completed. The restriction of Technical Specification 3.2.1 renders Technical Specifications 3.4.1.1, 3.4.1.2 and 3.4.1.3 (issued with Amendment No. 49 May 30, 1978) ineffective. These Technical Specifications provide the LCO's for reduced loop operation. Although not authorized to operate in this mode, the Technical Specifications were issued to facilitate the ease of future amendments by minimizing the number of changes to the Technical Specifications. Therefore, if an analysis for N-1 loop operation i i 1
is performed by the licensee and approved by the NRC, only the footnote of Technical Specification 3.2.1 has to be removed. Based on our review, we find that the restrictions presented in Technical Specification 3.2.1 and the requirements of 3.0.3, in lieu of approved analytical support for N-1 loop operation, are consistent with our criteria. Therefore, we conclude that Topic IV-1. is completed and acceptably resolved for Yankee Rowe. =.. t] L e =.:. t l .1 i . - -. ~ _ ,}}