ML20083L817
| ML20083L817 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek, Callaway, 05000000 |
| Issue date: | 04/13/1984 |
| From: | Petrick N STANDARDIZED NUCLEAR UNIT POWER PLANT SYSTEM |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| TASK-2.K.3.05, TASK-TM GL-83-10C, GL-83-10D, SLNRC-84-66, NUDOCS 8404170372 | |
| Download: ML20083L817 (3) | |
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5 en SNUPPS 9tanderdeaed NN Unit Power Mont Sysswn
's aione chyry nQ Nicholas A. Petrick Hoekville 5W ad 20eso Executive Director
.tmu se,etu April 13, 1984
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SLNRC 84-66 FILE: 0541 SUBJ:
Final Response to NRC Generic Letter No. 83-10 c M'r. Hiir0ld p. Denton, Director c
Office of Nuclear Reactor Regulation U.-S. Nuclea'r Reotilatory Commission Vashington, D. C. 20555 Docket Nos:
STN 50-482 and STN 50-483 references:
1.
SLNRC 83-0021, dated 4/22/83, Response to NRC Generic Letter No. 83-10 c 2.
OG-110, dated 12/1/83, Evaluation of Alternate RCP Trip Criteria 3.
0G-ll7, dated 3/9/84, Justification of Manual RCP Trip for Small Break LOCA Events
Dear Mr. Danton:
Reference I presented the SNUPPS Utilities plan for demonstrating compliance with the criteria for resolution of TMI Action Plan Require-ments Item II.K.3.5, " Automatic Trip of Reactor Coolant Pumps", which were established in letters from Mr. Darrel G. Eisenhut of the Nuclear Rejlatory Ccmmission to all Applicants and Licensees with Westingho'ise designed Nuclear Steam Supply Systems (83-10 c and d) dated February 8, 1983. The submittals which fulfill the commitments ir. the SNLPfr, plan nave been transmitted to you in References 2 and 3.
Sectfin'I of the attachment to NRC letter 83-10 e and d discusses " Pump Operation Criteria Ubich Can Result in RCP Trip During Transients and Accidents".
Subsection 1 of Section I presents guidelines for establish-ing setpoints for RCP Trip. The Westinghouse Owners Group (WOG) response to, this section of NRC Letters 83-10 c and d is contained in Revision 1 to the V0G Emergency Response Guidelines, which has been issued to member utilities. These guidelines will be incorporated into the plant speciric. operating procedures for Callaway Plant Unit No.1 and Wolf Creek Generating Station No. 1.
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- SLNRC 84-66 Page 2.
The RCP trip criterion being adopted in the Callaway Plant Unit No.1 and Wolf Creek Generating Station No.1 plant specific procedures not only assures RCP trip for all losses of primary coolant for which trip is considered necessary but also permits RCP operation to continue during most non-LOCA accidents, including steam generator tube rupture events up to the design basis double-ended tube rupture.
The generic applicability of the RCP trip criterion selected has been documented by the Westinghouse Owners Group in Reference 2, which has been submitted to the NRC for review.
The Westinghouse Owners Group has also submitted to the NRC, via Refer-ence 3, the justification of manual RCP trip for small break LOCA events. As stated above, these submittals completed the WOG documen-tation comprising'a generic reply to NRC Generic Letters 83-10 c and d.
Subsection 2 of Section I of the attachment to NRC Letters 83-10 c and d provides guidance for justification of manual RCP trip.
Subsection 2a requires that compliance with 10CFR50.46 be demonstrated in an Appendix K small break LOCA analysis given that the RCPs are tripped two minutes after the onset of reactor conditions corresponding to the RCP trip 4
setpoint. The Westinghouse Owners Group has generically verified, in Reference 3, _that predicted LOCA transients, presuming the two minute delayed RCP trip, are nearly identical to those presented-in Safety Analysis Reports utilizing the WFLASH Evaluation model. -Thus, the Final Safety Analysis Report for SNUPPS plants demonstrates its compliance with the Subsection 2a guidelines.
The WOG has also performed most probable, best estimate, WFLASH analyses to demonstrate, generically, compliance with-the guidelines presented in Subsection 2b of Section _I of the attachment to NRC Generic Letters 83-10 c and d.
These analyses identify that the minimum time available for operator action for the complete range of LOCA break sizes exceeds the value contained in N660; they show that reactor coolant pumps may_ be tripped at any time during a LOCA e'ent without resulting in excessive v
clad temperatures. The applicability information presented in the generic report affirms the applicability of this best estimate analyses to the SNUPPS plants. Therefore, in combination with the Subsection 2a justification cited above, the best estimate analyses? justify that manual RCP trip is acceptable for the SNUPPS plants when RCP trip setpoints. consistent with Revision 1 to the Emergency Response Guidelines are in use. Furthermore, the generic report demonstrates that no additional contingency emergency procedures are-required-to address the.
scenarios which may follow a missed RCP trip setpoint.. Based on the results-_of the RCP trip criterion study of Reference 2, RCS pressure has been chosen as the trip parameter for the SNUPPS plants. The degree of redundancy and the design features of the wide range RCS pressure instrumentation.(consistent with the function,l location, and environmental conditions) has been reviewed and availability is adequately _ assured for accident mitigation.
.s SLNRC'84 Page 3.
Operator training programs will employ lesson plans consistent with the results of ~ the Westinghouse Owners Group evaluations described in Reference 2 so that~ operator actions regarding RCP operation in conjunc-l f
tion with other accident mitigating systems will support p ant sa ety consistent with the SNUPPS Final Safety Analysis Reports.
In summary, the generic information presented by the Westinghouse Owners t-Group in References 2 and 3 along with the SNUPPS Utilities. plan of Reference 1 provides the response to NRC Generic Letters 83-10 c and-d 4
for the SNUPPS Utilities. The implementation of Revision 1 to the Emergency Response Guidelines in the plant-specific procedures with an appropriate RCP trip setpoint.specified will resolve all issues associ-ated with automatic tripping of the reactor coolant pumps.
Very ruly~yours,
-R&oc Nicholas A. Petrick J0C/nldla29&lbl&2 cc-D. F. Schnell UE G.RL. Koester KGE D. T. McPhee KCPL J. _Neisler/B. Little USNRC/ CAL W. Schum/A. Smith USNRC/WC W. Forney USNRC/RIII Z
s_.
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