ML19343A395
| ML19343A395 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 09/11/1980 |
| From: | Marisi A BOSTON EDISON CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| 80-218, NUDOCS 8009170329 | |
| Download: ML19343A395 (8) | |
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SOSTON EDISQN C O M PANY G =ana6 Cresces eco sortsvo= Stacar BOSTON. M ASSACHUSCTT5 02199
""""I" BECo. Ltr. #80- 218 September 11, 1980
.Mr. Thomas d. Ippolito, Chief Operating Reactors Branch #3 Division of Operating Reactors Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D C 20555 License No. DPR-35 Docket No. 50-293
References:
(A) NRC Letter dated 6/19/80, T. A. Ippolito (NRC) to G.-C. Andognini (BEco) with enclosures (B) BECo Letter #80-38, dated 2/29/80, G. C. Andognini (BECo) to T. A. Ippolito (NRC)
(C) BEco Letter #80-97, dated 5/29/80, G. C. Andognini (BECo) to T. A. Ippolito (NRC)
Response to NRC Staff Questions on Fire Protection
Dear Sir:
In Reference (A) Enclosure 2 & 3, members of your staff involved in the review of Pilgrim Station's Fire Protection Program, requested further infor=ation pertaining to some of Boston Edison Company's previous submittals. The attach-ment to this letter provides you with the supplemental information as requested.
If during your review, you have any further questions on these is' sues, please contact us at your convenience.
Very truly yours, 00(
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8009170 32$
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-ITEM 3.1.14 - EXPOSED STEEL PROTECTION The following is Intended to reiterate and ampilfy information already provided to you in Reference (b):
s (a) The installation of fireproofing material on the exposed structural steel at the Pilgrim Station Unit #1 was completed on February 8, 1980.
(b) The design constraints agreed upon between Boston Edison Company and the NRC at a conference call on October 16, 1979, were Ir:orporated into the design and are reflected in the installation of the material.
in response to your concerns as reflected in Enclosure (2) to your letter, we offer the following details:-
All clamps located on fireproofed structural beams were covered entirely with the fireproofing compound. With regard to rods, none were found to be attached to the structural members which were fireprocfed. All attach-ments except for the unistrut channels were covered to the extent permitted by the fireproofing design.
Unistrut channels attachments to structural members were filled solid to a distance of 2" beyond the fireproofing.
2.
Certain small beams / columns were excluded from the fireproofing modification after an analysis was conducted to prove that their loss would have no adverse effect on plant safety.
3.
All exposed structural steel members in the Reactor Building open area on El. 23'-0" were fireproofed.
4 No Marinite interface was Installed in any area of the plant during fireproofing of the structural steel members.
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ITD4 3.1.16 - SELF CONTAINED BREATHING APPARATUS The cascade air filling system at Pilgrim Nuclear Power Station has
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four (4) ASME Rece* vers in conjunction with the air compressor. With the compressor rer..ilng, Storage Receivers are refilled as air is drtwn from them providing completely filled Receivers at all times. On a conservative approach, maintaining the Scot air bottles at 70 -80 F, one 0
bottle can be filled in 4-5 minutes from each charging whip to a total of four bottles at one time.
In an actual emergency, it has been evaluated that bottles can be filled at a quicker rate.
Pilgrim Station has presently on site at least 20 spare bottles which provide ten men with two spare bottles each (30 min. capacity per bottle). With the capacity to fill four bottles at a time within 4-5 minutes, it can be conservatively assumed that the cascade filling system will be able to fill air bottles at a sufficient rate to supply 10 men with air for at least six hours-e w,
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ITEM 3.1.17 - COMMUNICATION SYSTEMS The in-plant antenna communication system at Pilgrim Nuclear Power Station is capable of communicating between the Transmitter / Receiver and the Base Radio Station (located in the guardhouse) and portable units I.n all areas of the plant including the Control Room.
The Station's primary containment is inerted during plant operation and is not accessible.
For the above reason, we hava not provided backup communica-tion means for primary containment use. However, during an outage when the primary containment is de-Inerted, BECo has provided a Gai-tronics private line hard wired phone system for communication purposes. Portable radios can also be used in the primary containment for communication purposes during an outage.
The physical routing of the communication antenna throughout the plant is such that it precludes the antenna f rom being subjected to a common fire with the fixed communication system.
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-ITEM 3.1.19 - PENETRATION SEALS A complete set of the Penetration Seals test reports was transmitted to the NRC under Reference (c).
Since then, additional copies were provided as they became available.
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The above qualification tests were performed on typical penetration seals based on requirements detailed in Section 3.1.19 of the SER to Pilgrim Station.
IEEE Standard 634 and ASTM Standard 119, which represent the
" State-of-the-Art" in Penetration Seal Qual ification, were used as guide-lines throughout the engineering effort and the performance of the tests.
Boston Edison Company would like to take this opportunity and express some of our concerns with regard to the NRC's requirement to apply dif ferential prossure while testing the penetration seals:
We were not advised by the NRC of a dif ferential pressure requirement for qualification testing prior to the issuance of the SER in December 1978 nor at any time prior to the actual testing of the seals in July 1979.
In fact, it was only through Reference (a) that the NRC has, for the first time, notified SECo of such a requirement.
The NRC, as part of its concerns, specifies the differential pressure for the qualification process' to be the " maximum pressure differential a fire barrier in the plant is expected to experience".
Boston Edison Company feels that the above statement warrants further clarification in view of the analytical difficulties one might encounter to set a definite figure to this maximum differential pressure. Furthermore, the present " State-of-the-Art" methods available to conduct such qualification testing need further elaborate study and Industry technical participation prior to establishing any meaningful and viable criteria.
It is to be noted that BECo has expended large sums of money and time to engineer and perform its cualification testing.
To impose a requirement as vague as this pressure differential to already completed qualification testing will primarily disrupt the basic objective of the present implementation p rogram.
We Intend to proceed with the implementation of a modification program to up-grade all the penetrations at Pilgrim Station that-do not meet the SER require-ments.
For that purpose, we have completed an extensive penefration survey at Pilgrim Station, the results of which are to be used in the design and installation phases. Actual implementation has not commenced yet since the suggested fixes which we have qualified in our testing program require your review as mandated in the SER. BECo requests your early review of the test reports and their conclusions.
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Item 3.2.7 D.C. POWER SYSTEM HAZARD ANALYSIS
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In response to the NRC's concerns over BECo's earlier submittals on Item 3.2,7,'"DC Power System Hazard Analysis", we wish to add the following information to the analysis, After a short description of the DC system we will identify in detail the physical routing of each redundant system with respect to oth(es and will provide our basis for concluding that the safe shutdown of the plant will not be jeopardized.
A.
SYSTEM DESCRIPTION 1,
125V DC Safety Division A 125V DC Safety Division A System consists of Control Bus D16 feedir.g MCC D7 and Distribution Panel D4, The Control Bus is
-fed from 480V AC MCC B15 through Battery Charger D11. MCC B15 is fed from 480V Load Center Bl.
Load Center B1, Battery Charger D11, Control Bus D16 and Distribution FTnel D4 are all located in Switchgear Room A (Fire Area 2,2) in tha Turbine Bldg,-Elev 37' 0",
MCC B15 is located in RBCCW Pump Room A in the Reactor Bldg. Aux, Bay Elev, (-)1'-0". MCC D7 is located adjacent to the CRD Module area (South-westl of the Reactor Bldg. Elev, 23'-0" (Fire Area 1,101, 2,
125V DC Safety Division B 125V DC Safety Division 8 System consists of Control Bus D17 feeding MCC 08 and Distribution Panel D5. The Control Bus is fed from 480V MCC B14 through Battery Charger D12, MCC B14 is fed from 480V
.l Load Center B2, Load Center B2, Battery Charger D12. Control Bus D17 'and Distfibution Panel D5 are all located in Switchgear Room B (Fire Area 2.1) in.
the Turbine Bldg Elev. 23'-0",
MCC B14 is located in RBCCW Pump Room B in the Reactor Bldg. Aux, Bay Elev. (-ll'-0"7 MCC D8 is located adjacent to the CRD Module area (North-westl of the Reactor Building Elev. 23'-0" (Fire Area 1,10),
3.
250V DC Safety Division B (Only) 250VDCSafetyDidisionBSystemconsistsofControlBusD10 feeding MCC 09. The Control Bus is fed from 480V AC MCC B14 through Battery Charger 013, MCC B14 is fed from 480V Load Center B2, Load Center B2, Battery Charger D13 and Control _ Bus D10 are all located in Switchgear Room B (Fire Area 2.11 in the Turbine Bldg, Elev 23'-0",
MCC B14 is located in RBCCW Pump Room B in the Reactor Bldg. Aux. Bay Elev.
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(-)1'-0",
MCC D9 is located adjacent to the CRD Module area (North-west) of the Reactor Bldg. Elev 23'-0" (Fire Area 1,101, 9
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Backup Battery Chargers 125V DC Backup Battery Charger D14 is located in Switchgear Room A and is fed from 480V MCC B10 (Division X). B10 is located in the Cable Spreading Room. 250V DC Backup Battery Charger D15 is located in Switchgear Room B and is fed from MCC B10.
B.
PHYSICAL SEPARATION l.
Between Redundant Equipment Switchgear Rooms A and B are, physically separated by space and 3-hour fire rated barriers thus providing ample separation between B1, Dil, 4
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D16 and D4 of Safety Division A and B2, D12, D17 and 05 of Safety Division B.
The common barrier between these rooms is a floor.
Structural Steel members in Switchgear Room B have been fire proofed.
Even though both D7 & D8 are located in Fire Area 1.10, there is more than 35 feet of spatial separation between them. 480V MCC's B15 & B14 are located in different rooms, separated by 3-hour rated fire walls.
2.
Between Redundant Cables As stated earlier, Dll, D16 and D4 are located in Switchgear Room A (Fire Area 2.2). The electrical cables which are rou'ted between these s
equipment are in Fire Area 2.2.
Cables for the redundant System which are routed between D12, D17 and DS are in Fire Area 2.1.
i The cable between 480V MCC B15 and Dil is routed southward from RBCCW Room A, through the Condenser Bay and into Switchgear Room A.
The redundant Cable between B14 and D12 is routed eastward from RBCCW Pump j
Room B through the Reactor Building Eley. 23'0" (Eire Area 1.10),
southwards through the Condenser Bay and into Switchgear Room B.
There is a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire barrier-separation between MCC's B15 and B14 The cables of both the redundant Systems are in different fire Areas except when they are routed through the Condenser Bay.
In the Candenser Bay there is only one location where the redundant cablps are separated by a minimum of 6 feet of space. The whole Condenser Bay 4
r area is protected by.a Water Sprinkler System.
Cables routed from Control Bus D16 to MCC D7, from Control Bus 017 to MCC D8 and from Control Bus D10 to MCC 09 are routed through the Reactor Building Elev, 23'-0".
t The physical separation between redundant systems' cables has been described in our earlier subnittal (Item 3.2.11 " Safe Shutdown Analysis,"
t C.
ANALYSIS AND CONCLUSIONS After reviewing the equipment location, cable routing and the design of the DC System, we can establish the following:
1.
The combined loss of the cables connecting DC Division A and DC Division B Battery Chargers to 'their respective 480V ~AC MCC's will not affect the availability of 125V DC power for the reasons specified below:
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e- (a) The availability of a Backup Charger which is capabir of being powered both from Diesel Generators A and B (through MCC 10 Division X).
(b) The characteristics inherent to the design of the DC System:
The Station Batteries are capable, in the event of a Lcss Of Offsite Power concurrent with a LOCA, of powe' ring all the loads required to mitigate the accident. Since no accident is assumed to occur concurrently with a fire, the batteries can supply all the power requirements during the 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of an assumed Loss Of Offsite Power.
2.
A physical separation of 35 feet between Safety Division B MCC's D8, D9 and Safety Division A MCC D7 along with other Fire Protection measures, preclude the possibility of both divisions damaged by the same fire (refer to Dwg. E-298 prepared for Fire Zone 1.10).
Safety Division A trays AK & AS are routed at a horizontal distance of 8 feet at an elevation of 36'-9" away from MCC D8. Electrical cables in both these trays have been sprayed both top and bottom with fire retardant Flamemastic 77 for the whole area.
Boston Edison Co. is presently installing a large number of smoke detectors (Photo-electric and Ionization types) in this area to provide an effective early warning system that wiil detect and help in suppressing any transient or fixed fire that may affect both redundant trains.
From tests performed at Sandia Laboratories on the use of Fire Retardant coating it can be safely assumed that coating of electrical cables with certain approved materials (such as Flamemastic 77),
provides 30-40 minutes of, protection. This is ample time to detect and suppress any prospective damaging fire.
In addition, as explained in our original submittal for the DC Hazard Analysis, a connon loss of both 125V DC MCC's D7 and D8 loads will not jeopard.ize a Safe Plant Shutdown.
Even the new requirement imposed on the Licensees of a sustained Loss of Offsite Power for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> will not affect the conclusions ~ that Safe Plant Shutdown will not be jeopardized. The loss of Diesel Generat~or Standby-Fuel Oil Pumps A and B (due to an assumed loss of both MCC's 07 and 08) can be tolerated for the period of 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> (the capacity of the Diesel Day Tank) during which alternate supplieseof fuel oil can be made available or an alternate DC supply for the pumps may be provided.
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