ML20028D382
| ML20028D382 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 01/07/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20028D381 | List: |
| References | |
| NUDOCS 8301190056 | |
| Download: ML20028D382 (3) | |
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NUCLEAR REGULATORY COMMISSION WASHHWGTON, D. C. 30585 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 66 TO FACILITY LICENSE N0. DPR-35 BOSTON EDISON COMPANY PILGRIM NUCLEAR POWER STATION DOCKET NO. 50-293 1.0 Introduction Three-hour fire-resistant barriers are required to be installed as necessary to protect redundant systems or components necessary for safe shutdown.
In a submittal dated March 9,1977, Boston Edison Company (BEco, licensee) identified important fire areas and barriers and erroneously indicated that two fire barriers existed between three fire areas (Main Steam Tunnel, Turbine Building, and RHR Velve Room).
In fact, the Steam Tunnel can be included with either of the two ather listed fire areas. The Main Steam Tunnel was originally considered part of the Turbine Building and separated from the RHR Valve Room in the Reactor Building by a Class A (i.e.a 3-hour fire resistant) fire door. During plant modifications for a high energy pipe rupture outside of containment, a blowout panel with fire resistive characteristics was constructed between the Steam Tunnel and the Turbine Building. The Steam Tunnel could then have been associated with either the Valve Room or the Turbine Building, as it has a very limited fire loading and it is not redundant to either area. All BECo Drawings except for one (1) were so revised.
This particular omission ultimately led to the confusion that caused both the fire barrier and fire door to be listed and taken credit for when the Fire Protection System Review was later completed.
The March 1977 submittal also provided clarification which stated "... in Figure I-5, three-hour fire barriers with a three-hour door were supplied in l
the basic initial design between the south-east RHR valve room and Main Steam and Feedwater piping tunnel. However, the combustibles are non fluid and adequate spatial separation exists between each area and to redundant areas in the other parts of the Reactor Building, thus a fire door is not necessary and the walls could be derated to less than a.one-hour fire rating requirement,"
TM fire protection design objectives for safeguarding the reactor and turbine l
buildings on the basement level (e.g. the Main Steam Tunnel) tonsisted of (
three level defense in depth:
1)
Po fixed (i.e. installed) combustible loading in the Steam Tunnel and l
no transient combustible loading (e.g. controlled by Admin Controls);
2)
Lo# combunible loading (i.e. less than 10 lbs of equivalent wood per sq. ft. Ref. a) in the turbine b1dg basement, and an installed fire suppression system (e.g. sprinklers) to provide adequate and reliable mitigation; and 8301190056 830107
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PDR ADOCK 05000293 P
PDR I
2 i
3)
A three-hour Fire Resistance Rated Fire Barrier.
Although a thrte-hour rated fire dcor is not needed between the Steam Tunnel and the RHR Valve Room, a threc-hour barrier is necersary between the Steam Tunnel and the Turbine Building. The fire barrier between the Turbine Building and the Steam Tunnel is not a three-hour barrier and, is therefore, not considered functional at this time. The licensee was made aware on 12/3/82 by its Engineering Department, that Technical Specification (TS) action requirements (Section 3.12.F) should be initiated because of the missing fire door and non-rated blowout panel. As such, a continuous fire patrol was established, which has thus far resulted in radiation exposure to the personnel involved in the patrol which is contrary to the concept of keeping radiation exposure to As Low As Reasonably Achievable (ALARA).
2.0 Evaluation In order to reduce unnecessary radiation exposures to personnel involved in the continuous patrol, the licensee has requested that the TS be modified to allow a "once per hour fire patrol" in lieu of the continuous fire patrol now required.
The fire barrier installed in the Steam Tunnel was not tested by the Underwriters l
Laboratory (U.L.) and, therefore, it is not listed by U.L.
However, the material components of this barrier are similar.to U.L. designs and a Factory Mutual (FM) approved design. These assemblias are listed or approved for a 2 or 21/2-hour rating. By comparison, the Steam Tunnel Barrier has been concluded to be able to resist the thermal effects of fire for the same duration.
In addition to fire resistive materials, fire barriers must meet construction requirements (i.e. must be fastened together and to support members) sufficiently to withstand the fire and the standard Fire Hose Stream Test. The existing panel fastening detail is supported with " pressure relieving" fasteners in-stead of conventional rigid fasteners. The panel's ability to pass the Hose Stream Test is in doubt. However, large diameter hose streams cannot be played against either side of this fire barrier because of the physical plant con-figuration and excessively long distances (400-500 feet) to the nearest large.
diameter hose connection.
Subsequent to the March 1977 submittal, both a fire suppression system was installed in the Turbine Building and a fire detection system installed in the RHR Valve Room.
In addition, combustible loadings in the area of concern are low and transient loadings are administrative 1y controlled.
Based on these considerations, and the fact that the blowout panel is constructed of materials consistent with " rated" fire barriers offering protection for up t) te hours, we conclude that the one-hour fire patrol proposed by the licensee provides adequate protection against fires in thia area. Consequently, we find the licensee's proposed TS change acceptable.
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3 3.0 Environmental Considerations We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level i
and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the stand environmental impact and, pursuant to 10 CFR 551.5(d)(4) point of
, that an environmental impact statement, or negative declaration and environ-mental impact appraisal need not be prepared in connection with the issuance of this amendment.
4.0 Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of an accident previously evaltated, do:, not create the possibility of an accident of a type different from any evaluated previously, and does not involve a significant reduction in a margin of safety, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Dated: January 7,1983 Principal Contributor:
K. Eccleston l
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