ML20214K767
| ML20214K767 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 08/15/1986 |
| From: | Warembourg D PUBLIC SERVICE CO. OF COLORADO |
| To: | Berkow H Office of Nuclear Reactor Regulation |
| References | |
| P-86516, TAC-61578, NUDOCS 8608220086 | |
| Download: ML20214K767 (4) | |
Text
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Company of Colorado 2420 W. 26th Avenue, Suite 1000, Denver, Colorado 80211 August 15, 1986 Fort St. Vrain Unit No. 1 P-86516 Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Attention: Mr. H. N. Berkow, Director Standardization and Special Projects Directorate Docket No. 50-267
SUBJECT:
Record Storage Center Building at Fort St. Vrain
REFERENCES:
- 1) PSC Letter, Warembourg to Berkow, dated April 25, 1986, (P-86069)
- 2) Telephone Conference PSC to NRC on July 8, 1986
Dear Mr. Berkow:
This letter is in response to a request from Mr. Kubicki during the above-referenced telephone conference.
It is Public Service Company of Colorado's understanding from this telephone conference that the NRC reviewer (Mr. Kubicki) did not find any problems with the Record Storage Center building design as presented, but wants further clarification on several points in order to more definitely determine that the design will provide adequate protection for the records stored within the building.
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P-86516 Page 2 August 15,.1986 Following is PSC's understanding of the points which Mr. Kubicki wants addressed:
- 1) Steel in the roof of the building which is not protected from a fire within the building; 2) Halon fire suppression system design; 3) Halon concentration; 4) Reserve capacity of Halon tanks; 5) Discharge tests and test points; 6) Fire detection system design;-7) Basic description of alarms and related Control Room annunciation;
- 9) Portable fire extinguishers; and 10) Ratings of doors and dampers.
Clarification for each of these points is being addressed as follows:
- 1) Unprotected steel in the roof:
As was pointed out in the telephone conference, the two-hour fire rating of the building design is to protect the contents inside from a fire outside.
The fire load inside is addressed by the Halon system.
The combination of the Halon system and the fire detection / activation / annunciation system will provide protection for the records, and will also provide sufficient protection for the steel in the roof to prevent failure from a fire.
- 2) Halon fire suppression system design: System design will be in accordance with NFPA 12A.
- 3) Halon concentration:
The purpose of fire detection and suppression in the Record Storage Building is to minimize damage to the records.
Fire protection for this facility is divided into two categories: the Halon system and the fire brigade. The Halon system would primarily control any surface fires, and reduce the possibility of the development of a deep-seated fire.
PSC will assure a minimum Halon concentration of 7% for 20 minutes.
At this concentration, there is sufficient Halon present to extinguish a surface fire, yet there is no danger to personnel from Halon inhalation, so that no time delay for evacuation prior to Halon application is required. By the end of the 20 minute soak time, the fire brigade would be on the scene, and would be able to ensure that the fire, including any " hot spots" that may have developed, is completely extinguished.
- 4) Reserve capacity of Halon: The reserve capacity of Halon will be equal to the design quantity of Halon.
- 5) Discharge test:
After installation, but prior to putting the Halon system into service, a discharge test will be performed to demonstrate that the design concentration is maintained for the specified soak time.
P-86516 Paga 3 August 15, 1986
- 6) Fire detection system design: At this time, PSC is planning on using photoelectric detectors with an addressable detector base.
Zoning will be either cross zoning or single zoning with Halon activation upon smoke detection by two or more detectors in the zone.
- 7) Alarms and Control Room Annunciation:
Control Room annunciation is by the Pyrotronics Fire Equipment (XC-45143). The tie between this equipment and the fire detection panel associated with the Record Storage Building is through a zone of detection.
Upon activation of this zone, Control Room personnel are directed to investigate the fire panel alarms within the walkover structure of Building 10. These panels are located within the same vital area, with operator access through an unlocked door.
Upon investigation of an alarm, the Record Storage Building would be individually addressed and the detectors in alarm are identifiable at this location.
Local annunciation and alarms will consist of a single audible alarm inside and outside the structure; and visual alarms located at each exit, exterior to the structure.
- 8) Conformance to NFPA 12A and NFPA 72D & 72E: The Halon system will conform to NFPA 12A and the fire detection system will conform the NFPA 72D & 72E.
- 9) Portable fire extinguishers: Portable fire extinguishers will be installed in the Record Storage Center in accordance with NFPA 10.
- 10) Ratings of doors and damp ~ers: The building is to be fire rated at two hours.
In order to achieve this rating, the doors and dampers will be rated for three hours.
In addition to Mr. Kubicki's request, the concern has been raised as to whether the components of the new Record Storage Building have the potential to act as new missiles not previously evaluated for Fort St. Vrain in the event of a tornado.
It is PSC's conclusion that the masonry blocks or the concrete building roof are not new credible potential missiles.
This conclusion is based on the building's location which is outside of the plant's protected area and on the building design which has utilized considerable quantities of reinforcing steel and bar splices l
in connecting the roof to the wall sections. This design mitigates i
separation of building structural components for the generation of new missiles in the event of a tornado.
Miscellaneous structural
. P-86516 Paga 4 August 15, 1986 components, and the building contents are comparable to the existing inventory of potential missiles'. currently on site.
It can be conservatively concluded that these items have neither the weight nor shape to exceed the design conditions for the FSV design missile (fir
- plank, 4"
X 12" X 12' long, 105 lbs.) On this basis, we feel that the new Record Storage Building is not a source of new unreviewed potential missiles.
We hope that this letter clarifies the issues that you had questions about and, with our previous letter of Reference 1, provides you with the information you need to approve the design of the Record Storage Center building. As we stated in our previous letter of Reference 1, PSC requests a written NRC approval of the exceptions requested.
In order to ensure that the new Record Storage Center building will meet the NRC requirements, material procurement and building construction are being held pending NRC approval of these exception requests.
For this reason, your prompt attention to this matter would be greatly appreciated.
If you have any questions concerning this matter, please contact Mr. M. H. Holmes at (303) 480-6960.
Very truly yours, 4
b W Woud D. W. Warembourg, ger Nuclear Engineering Division DWW/JW:pa
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