ML20149M911
| ML20149M911 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 02/23/1988 |
| From: | Shelton D TOLEDO EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 1493, NUDOCS 8802290251 | |
| Download: ML20149M911 (2) | |
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TOLEDO Docket No. 50-346
& Cetertr burgy Ccem License No. NPF-3 DONAU3 C. SHELTON Serial No. 1493
- w. nmi. sam (419] 249 P300 February 23, 1988 United States Nuclear Regulatory Commission Document Control Desk Washington, D. C.
20555
Subject:
Main Feedwater Pump Trip Test Gentlemen:
The purpose of this letter is to provide an update of Toledo Edison's plans for performing a trip of one Main Feedwater Pump with the reactor at high power. This trip was originally intended to be performed prior to the start of the fifth refueling outage; however, further evaluation has indicated that it is more prudent to conduct this test after completion of several plant modifications to be completed during the outage. Therefore, the test will be performed after power ascension following the fifth refueling outage.
Documentation for closure of the System Review and Test Program (SRTP) was provided by Toledo Edison in letters dated March 23, 1987 (Serial No.
1-716), June 1, 1987 (Serial No. 1388) and December 14, 1987 (Serial No.
1422). The December 14, 1987 letter also expressed the Company's position that, while not necessary to close the SRTP, it is nonetheless desirable to perform a trip of one Main Feedwater Pump with the reactor at high power.
Mr. A. W. DeAgazio, NRC Project Manager, was informed during a telephone conversation on February 8, 1988 that Toledo Edison had determined that the most prudent time to perform the test was after the upcoming refueling outage.
Several factors contribute to the decision to perform the test after the refueling outage.
The major factors include:
1)
The purpose of the test is to gather additional data for an engineering evaluation regarding plant response to a loss of one Main Feedwater Pump from 80% to 90% reactor power. The present reactor configuration and condition relative to the number of control rods in Group 7 and the large negative temperature coefficient, respectively, would result in a rapid reactor power runback rate. The data collected from a Main Feedwater Pump trip in this configuration would need to be correlated to the post refueling outage configuration (Gray axial power shaping rods (APSRs) and eight versus twelve control rods in Group 7), and, therefore, would contain uncertain-ties. The moderator temperature coefficient at beginning-of-life (BOL) conditions and the Gray APSR and Group 7 configurations will result in a slower reactor power runback rate and, therefore, effects THE TOLEDO EO! SON COMPANY EO! SON PLAZA 300 MAD: SON AVENUE TOLEDO, OH!O 43652 8802290251 080223 PDR ADOCK 05000346 P
C Docket No. 50-346 License No. NPF-3 Serial No. 1493 Page 2 from the worst case BOL conditions can be collected and assessed for the remainder of core life with a long term configuration, thereby ensuring the assessment is more accurate and meaningful.
2)
The Reactor Protection System (RPS) high pressure trip setpoint has been proposed to be raised from 2300 psig to 2355 psig during the refueling outage (Serial No. 1464). This change should provide additional assurance that the plant will respond appropriately to the feedwater transient without the reactor tripping.
In further support of Item 1 above, performing the test with the RPS setpoint at 2355 reflects the plant's planned long term configuration, thereby providing more meaningful results.
3)
Currently, three Main Steam Safety Valves are inoperable, which limits allowable Reactor power to approximately 80 percent.
The Main Steam Safety Valves will be refurbished during the refueling outage, therefore, allowing the conduct of the test at a significantly higher power level (up to 100 percent power).
As stated above, the single Main Feedwater Pump trip testing is not required to satisfy any previous commitments; however, it may be useful in identifying plant changes necessary to improve reliability.
Completion of this testing early in Cycle 6 will provide optimum conditions for data collection.
If you have any questions concerning the above, please contact us.
Very truly yours,
/ ).--
RMC:bam ec: DB-1 Resident Inspector A. B. Davis, Regional Administrator A. W. DeAgazio. NRC/NRR Project Manager