ML20113D629
| ML20113D629 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 04/08/1985 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | John Miller Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8504150444 | |
| Download: ML20113D629 (3) | |
Text
p.
P BALTIMORE GAS AND l
ELECTRIC CHARLES CENTER.P.O. BOX 1475 BALTIMORE, MARYLAND 21203 April 8,1985 AMHUR E. LUNDVAM. JR.
vice pacsioce SUPPLY Director of Nuclear Reactor Regulation Attention: Mr. 3. R. Miller, Chief Operating Reactors Branch #3 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
Calvert Cliffs Nuclear Power Plant Units Nos.1 & 2; Dockets Nos. 50-317 and 50-318 Containment Vent / Hydrogen Purge System Gentlemen:
Your letter dated December 14, 1984, requested additional information concerning the functional capabilities of containment isolation valves MOV-6900 and MOV-6901.
The valves serve the containment vent / hydrogen purge system which is the subject of our license amendment applications dated December 22. 1983 and March 26, 1984. The requested information is attached, if you should have any further questions, please do not hestiate to contact us.
Very truly 'ours, jo Y
&,lt ~
AEL/BSM/vf Attachment cc: D. A. Brune, Esq.
G. F. Trowbridge, Esq.
Mr. D. H. Jaffe, NRC Mr. T. Foley, NRC Mr. 3. C. Ventura, Bechtel 8504150444 850400 B(f) pDR ADOCK 05000317 p
PDR i) )
i
Attachment BG&E RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE CONTAINMENT VENT / HYDROGEN PURGE SYSTEM ISOLATION VALVES (MOV 6900 AND MOV 6901)
- 1. The licensee has not defined the maximum pressure resulting from the pipe break (LOCA or steam line) case postulated. Thus, the staff could not determine that this is the worst condition with regard to loads on the valve.
Response
The me.ximum pressure resylting from a loss-of-coolant accident ranges frgm 41.5 psig (at t=8 seconds,19.0 ft break area) to 47.5 psig (at t=45 seconds,2.0 ft break area). The maximum pressure resulting from a main steam line break is 49.2 psig (at t=65 seconds). The containment vent / hydrogen purge system isolation valves will close within 25 seconds, assuming a pipe break coincident with a loss-of-offsite power. Thus, the maximum pressure acting against the closing valve will be approximately 45 psig, considering all pipe break cases (see Section 14.20, CCNPP Updated FSAR).
- 2. The licensee has not described in detail the methodology used for dynamic torque prediction and/or pressure related force predictions. The various factors affecting valve closure, such as stem or packing loads must be included in the methodology.
The staff is not able to conclude that the methodology used is acceptable.
Response
MOV-6900 and MOV-6901 are 4-inch,150 lb. Velan gate valves with Limitorque motor operators and were installed as qualified containment isolation valves as original plant equipment. Velan seismic analysis BB4-600GL-300 (Reference
- 1) describes the methodology used to conservatively demonstrate that the valves will be capable of functioning under all load conditions. These load conditions include a combination of seismic forces, differential pressure, stem trust and torque, and gland packing friction loads. All required load conditions were satisfied for all critical valve components.
In addition, Reference 2 provides the results of a test conducted by Velan to confirm the capability of the valve to operate against a differential pressure of 60 psi.
In this test, the measured valve stroke time was less than 10 seconds.
References 1 and 2 are available for viewing at BG&E offices, if desired.
- 3. The licensee has not submitted a stress analysis report, for example a stress analysis associated with a static deflection test or seismic analysis. The stress analysis l
m considers the critical valve parts in the valve, applies to the appropriate load or load combination, uses allowable stresses per applicable codes / standards or conservative values where codes / standards do not apply, and demonstrates that the allowable stresses are not exceeded. Thus, the staff can draw no conclusion about the integrity of the valve or the margins available during closing of the valve.
Response
See response to Item 2, above.
- 4. The licensee has not demonstrated that the operator has sufficient torque or force margin available to stroke and seat the gate from its initial open position under the accident condition postulated.
Response
See response to item 2, above.
- 5. The licensee has not demonstrated that the torque or force absorption rating of the valve operator is not exceeded by torques or forces developed during closure, nor has he addressed the adequacy of the interfaces (e.g., stresses in bolts) between the operator and the valve.
Response
See response to item 2, above.
- 6. The licensee, as a part of demonstrating reliability of containment isolation, has not demonstrated that the purge and vent valves and their operators are capable of withstanding the effects of the safe shutdown earthquake for which the plant was designed. A valid seismic qualification document was not submitted or referenced.
Response
See response to item 2, above.
References
- 1. Velan letter from R. Knievel to R. C. Williams (Bechtel Associates), " Seismic Analysis for Velan Motor-Operated Valves," dated October 12,1972. Encloses Velan Seismic Analysis BB4-600GL-300,for 4"- 150 lb. B. B. Gate Valve.
- 2. Velan letter from A. T. Quintin to B. S. Montgomery (BG&E) dated March 18, 1985.
Encloses Velan Hydro Test Report No. P-35327, Item //23 for Velan 4" - 150 lb. Gate Valve with Limitorque SMB-00-5 operator, dated May 4,1973.
2 i