ML20128C029
| ML20128C029 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek, Callaway, 05000000 |
| Issue date: | 05/21/1985 |
| From: | Petrick N STANDARDIZED NUCLEAR UNIT POWER PLANT SYSTEM |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19344B918 | List: |
| References | |
| SLNRC-85-15, NUDOCS 8505280149 | |
| Download: ML20128C029 (5) | |
Text
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SNUPPS Standardized Nuclear Unit Power Plant System 5 Choke Cherry Road Rockville, Meryland 20850 (301)869 8010 May 21, 1985 SLNRC 85-15 FILE: 0278 SUBJ: Equipment Qualification Justifications for Interim Operation (JIO)
Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C.
20555 Dockets No.: STN 50-482 and STN 50-483
References:
1.
SLNRC 84-0135, dated Decunber 21, 1984: Same Subject 2.
SLNRC 85-14, dated May 9, 1985: Same Subject
Dear Mr. Denton:
Enclosed are revised pages to be inserted into the Justification for Interim Operation (JIO) submitted by Reference 1.
This JIO had been previously re-vised by Reference 2, and the enclosed revised pages address NRC staff ques-tions which were raised during review of Reference 2. Also enclosed is a sketch of the Incore Thermocouple System with new-style Reference Junction Box which is installed at the Wolf Creek Generating Station.
The enclosure contains both proprietary and non-proprietary versions of the revised pages to be consistent with the JIO submitted by Reference 1.
Very truly yours, N cholas A. Petric k MHF/ NAP /dkw19bl
Enclosures:
1.
Sketch of Thermocouple System 2.
Instructions for Revision of JIO cc:
G. L. Koester KGE B. Little USNRC/ CAL J. M. Evans KCPL G. C. Wright USNRC/RIII D. F. Schnell UE D. R. Hunter USNRC/RIV H. Bundy USNRC/WC f
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En' closure 2 Instructions for Inserting Revised Pages Into Interim Justification Position ESE-43 and ESE-44 A.
Westinghouse Proprietary Class 2 version:
Remove Insert Page 8 Page 8, Rev. 5/21/85 Page 9, Rev. 5/21/85 B.
Westinghouse Class 3 version:
Remove Insert Page 8 Page 8, Rev. 5/21/85 Page 9, Rev. 5/21/85
WESTINGHOUSE CLASS 3 5
~
- Sununary of Results for New-Style RJB Components
- The testing of the components of the core exit temperature monitoring system located inside containment demonstrated that the signal was maintained al-though errors were experienced at various times during the. test. For example, as noted above, the splices and adaptors experienced a signal deviation of 20*F during HELB/LOCA simulation. Westinghouse performed an evaluation of
- the errors experienced during qualification testing. Simply adding the esti-
. mated errors from the test results for each separate component yields a' total error of approximately 75'F.
The effect of this error on core exit thermocou-ple system functions was evaluated for the system functions applicable to the
~ SNUPPS plants, i.e., ' reactor coolant system subcooling margin calculation 'and inadequate core cooling determination. As described in Westinghouse letter to the NRC, NS-NRC-85-1325, dated May 9,1985, the thermocouple system error magnitude is. sufficient to provide an acceptable indication of inadequate core cooling. The two decision points in the generic Westinghouse Owners Group Emergency Response Guidelines (ERGS) for this function are indication of core
- exit thermocouple temperature greater than 1200*F and core exit thermocouple-temperature greater than 700*F in conjunction with Reactor Vessel Level.Indi-cating System (RVLIS) indication below the core midplane. Westinghouse has made recommendations for changing the 700*F to 900*F to accommodate the in-creased thermocouple system inaccuracies.
Procedural changes have been imple-
- mented at Wolf Creek Generating Station to incorporate this recommendation.
Callaway Plant will' implement the appropriate changes when the new-style RJB thermocouple system is installed. No change to the 1200*F decision point is required because an uncertainty of up to 200*F is acceptable for this decision point.
The thermocouple system inaccuracies in harsh environments are excessive for the ERG function of core subcooling calculation. Therefore, Westinghouse has recommended that the SNb?PS plants use the wide range reactor coolant system resistance temperature detectors (RTDs) for subcooling calculations. The wide range RTDs have been qualified under Westinghouse qualification program ESE-6.
8 Rev. 5/21/85
WESTINGHOUSE CLASS 3 The procedural changes required to employ wide range reactor coolant system RTDs for subcooling calculations have been implemented at Wolf Creek Genera-ting Station.
The appropriate procedural changes will be implemented at Calla-way Plant when tna.new-style RJB thermocouple system is installed.
l Because of the differences in core exit thermocouple system design from plant to plant, the procedural changes required to accommodate the increased system inaccuracies are considered plant specific and do not require a change to the generic Westinghouse Owner's Group ERGS.
In addition, as described in the above Westinghouse letter to the NRC, Westinghouse is continuing to define the final system accuracies resulting from the qualification program. The SNUPPS Utilities will follow the course of this effort at Westinghouse in conjunction with the SNUPPS independent review of NSSS qualification programs.
9 Rev. 5/21/85