ML20210C773
| ML20210C773 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 09/05/1986 |
| From: | Walker R PUBLIC SERVICE CO. OF COLORADO |
| To: | Gagliardo J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| IEB-85-003, IEB-85-3, P-86538, NUDOCS 8609180425 | |
| Download: ML20210C773 (6) | |
Text
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$.ndr7cYaozoim R. F. WALKER PRESIDENT
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- s1 September 5, 1986 i
SEP i 21986 Fort St. Vrain Unit No. 1
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P-86538 Regional Administrator Region IV U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 Attention: Mr. J. E. Gagliardo, Chief Reactor Projects Branch Docket No. 50-267
SUBJECT:
Additional Information Regarding IE Bulletin 85-03
Response
REFERENCES:
1)NRCletter,Gagliardo to Williams dated 7/22/86 (G-86400)
- 2) PSC letter, Walker to Gagliardo dated 5/14/86 (P-86356)
Dear Mr. Gagliardo:
This letter provides additional information regarding Public Service Company of Colorado's (PSC) response to IE Bulletin 85-03, Motor Operated Valve Comon Mode Failures During Plant Transients Due to Improper Switch Settings.
In Reference 1,
the NRC requested additional information in two areas, as follows:
1.
The first question requested that PSC discuss:
"The method by which you determined differential pressure for the valves identified."
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P-86538 Page 2
'S:ptemb:r 5, 1986 PSC reviewed applicable design documents and operating procedures to determine the maximum expected differential pressure conditions during which the valves would be expected to open or close.
PSC's program for IE Bulletin 85-03 includes two systems, emergency feedwater and emergency condensate.
a.
The emergency feedwater system review includes valves-downstream of the boiler feed pumps, where the highest operating pressure identified in the FSV Reference Design Books is 3620 psia. Pump performance curves and system startup procedures were reviewed to determine a maximum expected differential pressure.
For both opening and closing, 4500 psi was chosen, based on the maximum valve operating pressure identified in the valve design specificaton. This value is conservative for valves downstream of the high head, variable speed, turbine driven boiler feed pumps IA and IC, as these pumps can be operated at reduced speed and head during valve operations.
It is also conservative for valves downstream of the motor driven boiler feed pump 1B, as a recirculation line bypasses sufficient flow to keep the differential pressure below 4500 psi. This assures that flow can be directed to the emergency feedwater header under all credible operating events, b.
The emergency condensate system is a lower energy system that was included in PSC's IE Bulletin 85-03 program to provide a second line of defense to assure core cooling.
The condensate system is normally operating for core heat removal and the maximum operating differential pressure of 366 psi was used in the Reference 2 submittal.
This is the highest pressure identified in the FSV Reference Design Books and process flow diagrams, and it would assure core cooling during all credible operating events.
In order to provide additional assurance that emergency condensate valves will operate properly, PSC has-increased their design basis differential pressure to 450 psi. This value assures capability to operate valves against the shutoff head of the condensate pumps (approximately 412 psig) with downstream piping completely depressurized, and it is conservative with respect to expected service pressures identified above.
A revised valve data sheet is included as Attachment 1.
l l
P-86538 Paga 3
- S:ptember 5, 1986 2.
The second question requested that PSC indicate:
"Whether or not you will determine switch settings prior to testing, and if so, how this will be accomplished."
PSC will record the "as found" switch settings for all valves -tested in accordance with IE Bulletin 85-03, except HV-2290 and HV-2291. This will be accomplished as part of PSC's procedure for ensuring that the valve operators are adjusted to provide the stem forces required to overcome any expected. differential pressures.
A load cell-type test device will be used to monitor operator performance.
Prior to any switch adjustments, the valves will be operated and the developed stem forces and switch setpoints will be recorded. This "r.s found" data will later be compared with any new settings and, consistent with the guidance provided in IE Bulletir. 85-03, the valve's operability will be evaluated in accordance with the applicable technical specifications.
The motor operators for valves HV-2290 and HV-2291 are being replaced during the m crent outage.
"As found" data for these valves will De obtained if the outage schedule will not be adversely affected.
If you have any quest' ns regarding this information, please contact Mr. M. H. Holmes at (303) 480-6960.
Very truly yours, k
(.d k 5 R. F. Walker Chairman and Chief Executive Officer R0W/SWC/ paw Attachments cc: U. S. Nuclear Regulatory Commission Document Control Desk Washington, D.C.
20555
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In.the Matter Public Service Company of Colorado
)
Docket No. 50-267 Fort St. Vrain Unit No. 1
)
AFFIDAVIT R.
F.
Walker, being first duly sworn, deposes and says: That he is Chairman and Chief Executive Officer, of Public Service Company of Colorado, the Lice'nsee herein, that he has-read the information presented in the attached letter and knows the contents thereof, and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
W. U d.).lf
- R. F. Walker Chairman and Chief Executive Officer STATE OF
('Aorhv COUNTY OF__ Nimpot)
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Subscribe a.nd sworn to before me, a Notary Public on this 5h day of Clu din /ug)
, 1986.
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My commission expires duazah Adj
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/.TTACHMENT 1 to P-86538 IE Bulletin 85-03 Motor Operated Valve Data Design Basis Valve Valve Operator Valve Function deltaP.(psi)
Open/Close HV-3108, Limitorque, 1A, 1B, 1C Boiler 4500/4500 HV 3109, Model SMB-4T, Feed Pump Discharge HV 3110, Motor Speed Isolation 10" stop is 1705 rpm
- check, 2500 lb, Rockwell Edward HV 31118, Limitorque, 1A, 1B, 1C Boiler 4500/4500 HV 31119, Model SMB-3, Feed Pump /
HV 31120, Motor Speed Emergency Feed 8" stop is 1720 rpm Header Isolation
- check, 2500 lb, Rockwell Edward HV 31208 Limitorque IB Boiler Feed 4500/4500 4" Globe, SMB-1 Pump Discharge 2500 lb, Motor Speed Bypass Rockwell is 1700 rpm Edward HV 31191, Limitorque, Emergency Condensate /
450/450 8" Gate Model SMB-0, Emergency Condensate
- Valve, Motor Speed Header Isolation 300 lb, is 1700 rpm Walworth HV 2237 Limitorque, Emergency Condensate /
450/450 HV-2238, Model SMB-4T,-
EES Header Isolation 8" Globe-Y, Motor Speed Loop 1, Loop 2 2500-lb, is 1685 rpm Rockwell l'
- Attachment 1 to P-86538 (Continu:d) b.
HV 2290
- Rotork, Emergency Condensate /
450/450 HV 2291, Type 70A, Reheater Isolation 6" Globe, Output Speed Loop 1, Loop 2 900 lb, is 29 rpm Velan HV 3133-1, Limitorque, Condensate Pump
' 450/450-HV 3135-1 Model SMB-0, Discharge Isolation 8" Gate, Motor Speed 300 lb, is 1700 rpm Walworth HV 3133-2 Limitorque, Condensate Pump /
450/450 HV 3135-2 Model SMB-00, Emergency Condensate 6" Gate, Motor Speed Header Isolation 300 lb, is 1700 rpm Walworth i
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