ML20211G229
| ML20211G229 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 06/09/1986 |
| From: | Tucker H DUKE POWER CO. |
| To: | Harold Denton, Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8606190335 | |
| Download: ML20211G229 (3) | |
Text
A1 COVER LETTER AND LAST PAGE OF ENCLOSURE REDISTRIBUTED DUE TO LAST PAGE OF 1
ENCLOSURE MISSH4G FROM XC's DUKE POWER GOMPm P.O. BOX 33189 CHAmLOrTE, N.C. 98949 m enons HAL B. TUCKER (7o4) 373 4631 m....,
DDCL.4. P.O.UCT3.s June 9,1986 3.
"Mr. Barold R. Denton, Directcr Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 ATTENTION:
B.J. Youngblood, Director PWR Project Directorate #4
Subject:
McGuire Nuclear Station Docket Nos. 50-369, -370
Dear Mr. Denton:
30, 1986, the NRC staff forwarded an ACRS letter By letter dated April regarding operation of McGuire without Upper Head Injection Systems dated April 16, 1986, and requested s Duke response.
The Advisory Consittee on Reactor Safeguards suggestion that Duka consider maintaining the disconnection of the Upper Head Injection System (UHIS) on a reversible basis until further calculations show operating conservatisms of McGuire without UHIS are similar to non-UHIS plants was prompted by the Sandia presentation which included, for information, a comparison of "best It was estimate" analyses for McGuire and a standard Westinghouse plant.
pointed out that the comparison was not conclusive due to variations in important input assumptions used in the Sandia TRAC-PF1/ MOD 1 analysis for The apparent lack McGuire and the TRAC-PD2 analysis of the standard plant.
of "best estimate" analyses which could be compared directly and the conser-vative nature of evaluation model analyses which hamper their use to provide comparisons of actual plant behavior, apparently led to the ACRS suggestion l
regarding additional analyses.
This In response to this suggestion, Duka provides the attached evaluation.
evaluation is based upon available analytical predictions and LOFT test results and demonstrates that the operating conservatisms for McGuire without The evaluation UBI are similar to those which exist for nos-UHIS plants.
model and "best estimate" analyses predict -Unilar plant responses during The refill /-
blowdown for McGuire without UHIS and the nan-UBIS plants.
reflood behavior is slightly different between the two plant designs but the l
evaluation model predicts similar clad temperature responses while the "best estimate" analyses show a clad reheating for McGuire which is greater than The refill /reflood clad that which is predicted for the non-UBIS plant.
reheating and higher blowdown clad temperature predictions from the Sandia i
j) 8606190335 860609
)
DR ADOCK 0D000369 PDR
x1 H.R. Denton June 9, 1986 Page 2 cnalysis compared to the TRAC-PD2' standard plant analysis are shown to result from the significant differences in assumed linear heat generation rates used in the two analyses. This conclusion is supported by a review of the LOFT Upon review of the evaluation model analyses, czperiments L2-2 and L2-3.
"best estimate" analyses, and IDFT data, Duke believes the existing predic-t tions and data are adequate to demonstrate that the operating conservatisms for McGuire without UHIS are similar to non-UBIS plants and that no further
' analyses are necessary.
The McGuire units will be operated during the upcoming cycles (1986-1987) with the UHIS isolated but not physically removed. In order to fully benefit from the analytical and licensing actions which resulted in the May 13, 1986 SER sad thus reduce plant maintenance, startup delays, and radiation exposure to personnel, the removal of the UHIS, including capping reactor vessel penetrations and removal of piping and components is currently scheduled for the 1987 refueling outages at McGuire.
Very truly yours, 0r $/Y' Hal B. Tucker RLG/jgm Attachment xc:
Mr. Darl Hood, Project Manager Division of Licensing Office of Nuclear Regulatory Counistion Washington, D.C.
20555 Mr. W.T. (Tdars NRC Resident :".nspector McGuire Nucie tr Station Dr. J. Nelson Jrace U.S. N. clear Regulatory Commission - Region II 101 Marietta Street, NW, Suite 2900 Atlant.a. Georgia 30323 Paul Boehnert ACRT t
VII) REFERENCES 1.
NUREG/CR-0492, " Experimental Data Report for LOFT Power Ascension Test L2-2", February 1979.
2.
NUREG/CR-0792, " Experimental Data Report for LOFT Power Ascension Experiment L2-3", July 1979..
3.
March 17, 1986 Letter from D. Debranich (Sandia National Laboratories) to J. J. Watt (USNRC) on "LOCA Calculation for a UHI PWR with the UHI System
~
Removed".
4.
NUREG-0896, " Safety Evaluation Report Related to the Operation of Seabrook Station, Units 1 and 2, Docket Numbers 50-443 and 50-444, Public Service Company of New Hampshire", March 1983.
5.
NUREG/CR-4183, " Pressurized Thermal Shock Evaluation of the H. B. Robinson Unit 2 Nuclear Power Plant", September 1985.
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