ML20023C496
| ML20023C496 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 04/29/1983 |
| From: | Brey H PUBLIC SERVICE CO. OF COLORADO |
| To: | Madsen G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| TASK-3.D.3.4, TASK-TM P-83158, TAC-46448, NUDOCS 8305170380 | |
| Download: ML20023C496 (2) | |
Text
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r Public Service Compimy @OcBrMD 2420 West 26th Avenue, Suite 1000, Denver, Colorado 80211
~
l April 29, 1983 Fort St. Vrain (7
Unit No. 1 P-83158 30
% E@ l'- M B 3 Mr. G. L. Madsen, Chief l
Reactor Project Branch 1 s
U. S. Nuclear Regulatory Commission PAY i 0 F:3 Region IV 611 Ryan Plaza Drive, Suite 1000 W,.,
Arlington, Texas 76011 DOCKET N0:
50-267
SUBJECT:
Fort St. Vrain Unit No. 1 Centrol Room HVAC Failure Criteria
REFERENCE:
NRC letter dated ifarch 14, 1983, Madsen to Lee Gentlemen:
We have reviewed your referenced letter and believe that the Fort St.
Vrain Control Room HVAC system satisfies the requirements of the single-failure criteria for Control Room habitability, as described below.
Our review of the Control Room HVAC System indicates that the system will operate satisfactorily during an incident involving a radiation or an on-site toxic gas release.
The preferred mode of operation during the incident is to place the system in a minimum makeup position and isolate the outside air supply while introducing filtered makeup air from the Turbine Building.
However, another acceptable mode of operation is to shutdown the supply and return fans and align the required dampers to isolate the Control Room from outside air.
Should control room habitability be necessary for an extended period of operation under these conditions, the FSV breathable Air System is available.
The Breathable Air System is currently being podified to provide an optional filtered intake for use during a nuclear incident.
(Completion scheduled for June 3, 1983) a}OO Y 8305170300 830429 PDR ADDCK 05000267 P
PDP
P-83158 Page 2 In the event that any of the dampers must be considered totally inoperable, we believe that the single-failure criteria is met by the
~ fact that every damper listed in your referenced letter has other dampers in series which will isolate the Control Room.
The only damper without an alternate means of isolation is the one upstream of C7507.
For failure of this damper we would keep C7507 running to assure no radiation ingress.
Failure of fans C7504X or C7505 would reduce system capacity but not disable system operation.
If either the supply or return fan is inoperable, dampers can be positioned to recirculate 100% of the air by using the operable fan. Cooling is obtained with one of two water chillers.
In considering all of the above equipment failures it is important to note that safe shutdown of the plant could be accomplished following any single failure of the HVAC System since all safe shutdown equipment in the Control Room has been qualified for the maximum temperature expected.
PSC considers the existing system adequate and does not anticipate further modifications.
Please contact J. R. Reesy at (303) 571-8406 with any questions on this matter.
Very truly yours, WAw b I
H. L. Brey,itanager Nuclear Engineering Division HLB /FWT:pa l
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