ML19305A351
| ML19305A351 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 03/09/1979 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TAC-6587, TAC-8730, NUDOCS 7903130386 | |
| Download: ML19305A351 (22) | |
Text
e MSP NORTHERN STATES POWER COMPANY M I N N E A geO LI S. M I N N E S OTA 5 5401 March 9, 1979 Director of Nuclear Reactor Regulation U S Nuclear Regulatory Commission Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 NRC Staff Evaluation of Fire Protection Program During the week of October 16, 1978, the NRC Staff conducted an on-site inspection of the fire protection program at the Prairie Island Nuclear Generating Plant.
The NRC Staff recommendations resulting from the in-spection, as well as additional staff concerns identified following the inspection, were provided to us in a letter dated November 21, 19 78 f rom A Schwencer, Chief, Operating Reactors Branch #1, USNRC.
In a letter dated January 2, 1979, Northern States Power Company provided initial responses to the NRC Staff Positions developed as a result of the on-site inspection.
In that letter, many of the Staff Positions could not be fully adressed because further investigation and review were required by the Prairie Island technical staff.
Our review of the NRC Staff concerns and positions is now complete.
The results of this review for all items not addressed in our January 2, 1979 letter are attached. We believe we have proposed corrective actions, where appropriate, to resolve all deficiencies uncovered during the NRC on-site inspection.
This submittal, combined with our earlier submittals on this subject, completes our review of the Prairie Island fire protection program and addresses corrective actions to resolve deficiencies noted during the independent NRC review of the program. Major submittals on Prairie Island fi.e protection are summarized below:
1.
December 8, 1976 and July 5, 1977 Comparison of Existing Fire Protection Provisic us to the Guidelines Contained in Standard Review Elan 9.5.1 7903130386
NORTHERN STATES POWER COMPANY Director of Nucler Reactor Regulation Page 2 March 9, 1979 2.
January 31, 1977 License Amendment Request with Proposed Fire Protection Technical Specifications 3.
March 11, 1977 and July 5, 1977 Fire Hazards Analysis and supplement 4.
May 18, 1978 Northern States Power Company Fire Protection Program Outline and Review of Guidelines Contained in NRC Document entitled, " Nuclear Plant Fire Protection Functional Responsibilities, Administrative Controls, and Quality Assurance," dated August 12, 1977 5.
January 2, 1979 and March 9, 1979 Response to NRC Staf f Evaluation of Fire Protection Program Please contact us if you have any additional questions concerning our fire protection program or our proposed corrective actions to resolve NRC Staff concerns and positions.
b.
L 0 Mayer, PZ Manager of Nuclear support Services LOM/DMM/ak cc: J G Keppler G Charnoff Attachments
hbrch 9,1979 PRAIRIE ISIAND NUCLEAR GENERATING PIANT SUPPLEMENTAL RESPONSE TO NRC STAFF FIRE PROTECTION POSITIONS Additions and modifications to our January 2,1979 submittal are grouped into two attachments:
1.
Responses to Original Staff Positions 2.
Responses to New Staff Positions Attachment (1) contains additional or modified responses to the Staff positions discussed at the fire protection inspection exit meeting held on October 20, 1978.
Following the exit meeting, the NRC Staff renumbered the Staff positions, deleting those considered to be resolved. A number of additional Staff positions were developed. Attachment (2) contains additional or modified responses to these new Staff positions.
This information, combined with our January 2,1979 submittal, completes our response to Mr Schwencer's letter of November 21, 1978.
Attachment (1) to NSP letter 41ated March 9, 1979 Director of Nuclear Reactor hegulation RESPONSE TO ORIGINAL STAFF FOSITIO_N PF-10 Water Screenhouse - Diesel & Electric-Driven Fire Pumps Staff Position The electric-driven fire pumps should be protected from diesel oil fires originating in the diesel driven fire pumps or their fuel systems, including their day tanks.
Licensee's Response The screenhouse basement floor is pitched south toward the six foot wide trench along the entire south wall of the building.
Re-ferring to NF-39260-2E, the plant proposes to install a 4" angle between the southwest edge of #11 cooling water pump base and the north wall of the screenhouse basement. With this arrangement, oil spilled in the area of the diesel engine or dcy tank would be contained in the west half of the room.
Natural drainage would be toward the south to the sump and not cast or north against the pitch of the floor.
PF-12 Water Screenhouse - Electric Motor-Driven Fire Pump Cables Staff Position Verification should be provided that no power or control cables for the electric motor-driven fire pumps are routed over the area of influence of a diesel fuel fire.'d**
Licensee's Response Review shows that a power cable in 4" conduit is routed over the area in question.
The plant proposes to encase the conduit with a protective insulation (refer to new position 28 for a description of the material).
If covering the conduit proves to be impracticable, a design change will be initiated to reroute this cable along the south and eaat walls.
t PF-13 Water Screenhouse - Diesel Driven Cooling Water Pumps - Floor Drains Staff Position Verification should be provided that fuel leakage from the diesel driven cooling water pumps or their fuel systems cannot spread to other areas of the water screenhouse via the floor drainage systems.
Licensee's Response Verification was made by running water into the floor drains and observing the outlets. Drainage from the trenches at the water entrance doors goes to the intake bay.
Drainage from the strainer room goes into the intake bay also. The plant proposes to install an angle across the opening at grid coordinates 91-Cl (NF-39260-lE) to prevent any drainage into the strainer room.
PF-21 Diesel Generator Rooms - Curbs Staff Position Curbs or ramps should be provided at the fire door between the two diesel generator rooms and at the door between generator room No. 1 and Fire Zone 27.
Li:cnace's Response A ramp of 2 inches will be installed in D-1 room which will be totally within the room thus eliminating the need to modify the fire door.
1-1
b PF-21 (con' t)
We do not agree with the recommendation to install ramps or curbs at exit doors (Zone 27). With ramps or curbs, oil leakage with deluge water would flood the room and overflow into Zone 27 anyway.
Zone 27 contains no safe-guards or equipment necessary for safe shutdown and has a very light fire loading.
Zone 27 drains to the turbine building sump.
PF-33 Auxiliary Feedwater Pump Rooms, Fire Zones 31 and 32 Pipe Trench Staff Position A concrete fire barrier should be placed in the pipe trench that passes through the AFW pump rooms at the boundary between the two rooms. Metal covers consisting of 5/16" thick steel plates should be placed over the portion of the pipe trench which runs through each room and should be fastened to the concrete floors to prevent movement and warpage of the plates due to a postulated fire.
Licensee's Response A concrete fire barrier will be poured at the mid-point of the room trench. The existing grating will be notched and a 1/4" thick checkered floor plate will be tack welded in place to provide resistance to buckling.
P F-34 Auxiliary Feedwater Pump Rooms - Water Damage Staff Position Verification should be provided that operation of the wet pipe sprinkler system in the AFW pump rooms will not damage equipment reeded for safe hot shutdown of the plant.
Licensee's Response For the equipment identified in the January 2,1979, re-sponse to New Staff Position PF-12, Safe Shutdown Requirements, all electrical circuitry in the auxiliary feed pump rooms is contained in waterproof cabinetry.
Funor water seepage may occur in a select few cases where control switches or stations protrude through their cabinet enclosures; however, there is re-dundant equipment available in all such cases.
In addition, manual operation of all such cases except the air compressors will provide the necessary shut-down requirements.
Water damage will not deter safe shutdown.
PF-35 Auxiliary Feedwater Pump Room - Hot Shutdown Panels Staff Position Verification should be provided that in the event of fire damage to a hot shutdown panel, safe shutdown can be accomplished using systems and equipment located outside the room.
Licensee's Response Of the equipment identified in the January 2, 1979, re-sponse to New Staff Position PF-12, Safe Shutdown Requirements, only the following have controls at the hot shutdown panels:
a.
Auxiliary feedwater pumps and associated valves.
1-2
PF-35 (con't) b.
Steam generator power operated relief valves.
c.
Charging pumps and boric acid transfer.
d.
Steam generator level indication.
e.
Reactor coolant pressure indication.
In all cases control of redundant equipment is available at the second hot shutdown panel; fire damage would affect only one train.
In addition, items a and b can be perforced manually, item c can be replaced by safety injection pumps (as noted in Safe Shutdown Equipment List) and items d and e are un-necessary since normal contro1 room indication is operable. Other equipment useable for plant shutdown that is not identified on the Safe Shutdown Equip-ment List would be operable from the control room.
PF-44 Fire Brigade Practice Sessions Staff Position Practice sessions should be held for fire brigade members on the proper method of fighting various types of fires that could occur in a nuclear power plant considering such factors as the magnitude of the fire, and the complexity and difficulty of fire fighting. These sessions should be designed to provida brigade members with experience in actual fire extinguishment and the use of emergency breathing apparatus under strenuous working conditions. The sessions should be in addition to the scheduled fire brigade training sessions and fire drills and should include fire fighting strategies, (i.e., simple plans showing fire fighting equipment locations, entry and egress points, ventilation, communications and emergency lighting locations and controls).
These practice sessions should be provided at regular intervals, but not exceeding a one year interval for each fire bri-gade member.
_ Licensee's Response We agree to schedule fire brigade practice sessions as described above at least annually. We cannot provide assurance, however, that 100% of the fire brigade members will be available to attend each scheduled practice session. Due ' to vacation, sickness, offsite training, and unexpected schedule changes, some fire brigade members may miss a session. Because of the amount of preparation and planning that goes into a practice session, it is impractical to schedule makeup sessions. We therefore propose tc require at least 85% of all fire brigade members to attend each practice session.
1-3
Attachment (2) to NSP letter dated March 9,1979 Director of Nuclear Reactor Regulation RESPONSE TO NEW STAFF POSITIONS PF-6 Fire Brigade Training Staff Concern The fire brigade will not maintain a high level of fire fighting expertise unless:
1.
Classroom instructions and fire drills are provided on a more frequent schedule than the proposed 6 month interval for classroom instructions and the semi annual fire drills; 2.
Fire brigade members are each evaluated during fire drills to assure their proficiency in fire fighting techniques; 3.
Periodic critiques of the fire brigade are performed by qualified in-dividuals independent of the plant staff to update and correct the existing fire fighting techniques.
Staff Position a.
Regularly planned meetings should be held every 3 months to repeat the initial classroom instruction programs over a two year interval, b.
During fire drills, an evaluation should be made at each fire brigade member's proficiency in the use of fire fighting procedures.
c.
Fire drills should be critiqued at three year intervals by individuals independent of the plant's staff, d.
Fire drilla should be performed at regular intervals but not to exceed 3 months for each fire brigade.
Licensee's Response a.
The classroom instruction program will be conducted annually and drills will be condu *ed twice annually for all brigades. There will be a session following each drill to critique the drill and discuss portions of the original training program. This results in at least three planned meetings each year. We cannot reasonably accamodate a more frequent meeting schedule and still satisfy all of the other requirements placed on our staff.
b.
Agree with the staff's position.
c.
Agree with the staff's position.
d.
With our six (6) fire brigades, this would require a minimum of 24 drills a year. We consider this excessive and are concerned it could lead to perfunctory performance on the part of those participating in the drills as well as an unwarranted state of confusion for others at the facility. We believe 2 drills per brigade per year is the maximum.
2-1
4 PF-ll Electrical and Mechanical Penetration Qualification Staff Concern The NRC staff has taken the position that all electrical and mechanical penetrations in fire barriers surrounding safety-related areas should be sealed by methods demonstrated effective by testing.
The licensee has identified typical electrical (cable and trays and conduits) and mechanical (pipes and ventilation ducts) penetration seals that exist at the plant. The licensee has provided some information concerning the adequacy of seals during the site visit and has stated that test results which demonstrated the effectiveness of the fire stops are not presently available.
Staff Position Demonstrate by test that the penetration seals presently installed in the plant have a rating equivalent to the fire severity present on either side of the seal using the test criteria and guidance as discussed in PF-1.
Any new penetration seals that arc installed in the plant in the future or existing seals which must be replaced should be qualified to the test guidance and criteria of PF-1.
Licensee's Response In response letter dated 4/18/78, a description of the typical cable pene-tration seal used at Prairie Island is described. The area surrounding pipe and conduit penetrations was sealed by a variety of material such as grout, thermal insulation wool, and polyurethane foam for penetration of large pipe (12 or more inches).
In 1975. a review of all safeguard room cable penetraions was conducted and repairs made as necessary.
In 1977, a review of pipe and conduit penetrations was conducted.
All of these seals were in place but some did not have the outer coating.
At that time Flamastic 71A was usti to coat all of the uncoated seals.
A review of the documentation verifying the criteria used in selecting the seal material was conducted.
It was concluded that the material and pro-cedure used has tne approval of the American Nuclear Insurers (formerly NEL-PIA) and met criteria for fire stops in effect at that time. We were unable to find data indicating that the seal as a unit had been tested.
The plant has received information on new materials which have been tested in accorda nce with ASTM-119 and which meet criteria for 3-hour fire stops.
We feel these new materials, silicone foam, Marinite board, Kaowool, and cellular concrete have or will have in the near future sufficient documen-tation for their qualified use.
We propose the use of these new materials in all future sealing work.
PF-12 Safe Shutdown Requirements Staff Concern The licensee has submitted a preliminary shutdown analysis. This shutdown analysis did not consider such items as the capability for makeup to the primary system during hot shutdown and the provisions for boration in achiev-ing and maintaining hot shutdown. The licensee has not developed fully the list of minimum systems needed for achieving and maintaining hot and cold 2-2
PF-12 (con't) condition. The licensee is continuing to refine the list of minimum systems and equipment needed for achieving and maintaining both hot and cold shutdown conditions. Further, the licensee is continuing the effort to determine the exact location of electrical raceways for those systems and auxiliaries required to safely shutdown and cooldown the plant.
Finally, the licensee hat not demonstrated that the plant can be safely shutdown in the event of a fire in any fire area.
Staff Position Provide a list of minimum systems and equipment need for achieving and maintaining safe hot shutdown and safe cold shutdown following a severe fire in the plant considering the following shutdown functions:
1.
Placing the reactor in a subcritical condition and maintaining the reactor subcritical.
2.
Bringing the reactor to safe hot shutdown ccnditions and maintaining it at hot shutdown for an extended period of time (i.e., longer than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />) using only onsite power sources and onsite water supplies.
3.
Maintaining the reactor coolant system inventory using only onsite sources of makeup water.
4.
Bringing the reactor to safe cold shutdown conditions within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> using either onsite or of fsite power sources.
Hot shutdown should be achievable from the control room or the remote shutdown panels. Where a fire in a given fire zone causes inoperability of hot shutdown equipment f rom the control room or remote shutdown panels, remote manual operation of valves and breakers is permissible provided it can be shown that there is sufficient time and manpower to accomplish these manual operations. Manual operation of valves and breakers and replacing of cables for achieving and maintaining safe cold shutdown is permissible provided it can be shown that these operations can be done within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Demonstrate that the plant can be safely shutdown using any one or com-bination of the following in the event of a fire in any fire zone:
1.
Redundant systems and equipment are located in separate fire areas.
(Fire areas are defined as areas bounded on all sides by three-hour fire rated boundaries.)
2.
If redundant systems are located in the same fire area, there is reasonable assurance that redundant systems will not be damaged considering potential exposure fires, flame spread characteristics and fire protection features within the zone.
(Note: Sole reliance should not be placed on active, automatic fire suppression systems.)
3.
An alternate shutdown system will be provided which is independent of the influence of the fire within the fire zone by rerouting cables and relocating equipment.
2-3
PF-12 (con't)
Licensee's Response Equipment required to place and maintain reactor in a subcritical hot shutdown condition (per unit):
a.
Steam generator safety valves b.
An emergency diesel generator c.
A battery d.
An auxiliary feedwater pump and associated valves needed to feed one steam generator c.
A station air compressor f.
A cooling water pump g.
A steam generator power operated relief valve h.
A boration path, either one of the following:
1)
Emergency boration which includes a charging pump, a boric acid transfer pump, a boric acid storage tank or refueling water storage tank and heat tracing associated with the path,
- 11) liigh head injection which includes a safety injection pump, a boric acid storage tank or refueling water storage tank, supply valves to pump and associated boric acid supply heat tracing.
i.
Steam generator level indication j.
Reactor coolant pressure indication Equipment needed to maintain the reactor coolant system inventory using onif onsite sources of makeup water.
The refueling water storage tank through one of the boration paths itemized in the response above will provide makeup.
Equipment needed to bring the reactor to safe cold shutdown conditions within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> using either onsite or offsite power sources, a.
Those items listed in the response above, items d through.j.
b.
In addition, the following:
1)
A residual hat removal pump, heat exchanger and valves needed for recirculation from and back to reactor coolant loop,
- 11) A component cooling pump, heat exchanger and componeat cooling loop isolation valves.
iii) Cooling water valves to supply the omponent cooling heat exchanger.
iv)
Reactor coolant temperature indication.
v)
Pressurizer level indication.
I 2-4
PF-12 (con't)
Demoastrate that the plant can be safely shutdown using any one o-com-bination of methods described in the staff position.
Licensee's Response We agree with the staff position and will demonstrate that the plant can be safely shutdown using the safe shutdown equiprent identified in the January 2, 1979, response to New Staff Position PF-12, Safe Shutdown Requirements.
This demonstration involves identifying locations of the safe shutdown equipment, control circuit components,and interconnecting wiring to de-lineate redundant equipment spatial or zone separation. Where such separation is insufficient to provide assurance that redundant systems will not be damaged additional fire protective measures or alter-nate shutdown equipment will be incorporated.
The identification processes is nearing the final stages of completion.
PF-13 Cable Spreading & Relay Room Alternate Shutdown Requirements Staff Concern The cable spreading and relay room contains cables, in close proximity, of redundant sys tems of both Units 1 and 2 that are required for safe shutdown.
The room is protected by a double shot CO,ble in the room and system actuated by thermal detectors.
Portable extinguishers are availa hose s tations are nearby near vicinity. Fowever, there is a heavy con-centration of combus tible cables, especially in the ceiling area of the room and access to this area is limited to the extent that manual suppres-sion of the fire would be difficult.
It is the staff's concern that (1)
CO, system may not be effective in suppressing a deep seated fire, (2) the spatial separation between redundant divisions of safe shutdown systems may not be sufficient to prevent an exposure fire f rom damaging both divi-sions.
Staff Position An alternate shutdown capability should be provided independent of the cable spreading and relay room such that the conditions specified for safe shutdown in PF-12 are met.
Licensee's Response Agree with the staf f position and propose to address the cable spreading and relay room as a part of the response to new position PF-12.
2-5
t 1
PF-15 Containmcat Fire Hose Standpipe Staff Concern During normal operation the containment hose stations are dry.
Following detection of a fire in containment it is necessary to remove c ontainmen t fire hose standpipe system flanges attached at the inner and outer containment boundaries and to install spool pieces in the fire water system. The licensee's description of his procedure to reestablish fire water to containment indicates that fire suppression water would not be available for a period of 6 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> following detection of a fire in containment because of containment integrity considerations prior to cooldown to 200*F.
A more timely method for providing fire water to containment hose stations is needed to assure prompt extinguishment of a fire within containment.
Staff Position The containment fire hose standpipe system should be solidly piped to the fire water supply header outside containment.
A valve may be provided on the outside of containment to maintain the fire water piping inside containment dry until needed to suppress a containment fire.
Licensee's Response Agree with the staff's concern and will provide a more timely method for providing fire water to containment.
Possible methods under investigation include a solidly piped supply header, use of available plant make up water, and use of available cooling water in containment.
PF-17 Diesel Generator Rooms - Penetration Seals Staff Concern Each diesel generator room contains approximately 700 gallons of combus-tible liquids.
The diesel generator rooms are located adjacent to each other at the 695' elevation and are contiguous to the east boundary of the auxiliary building in the vicinity of Firs Zone 58.
Fire Zone 58 contains redundant systems required for safe shutdown.
The walls surrounding the diesel generator rooms have a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire resistance.
However, the licensee is not certain that the penetration seals in these walls have a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire resistance.
2-6
PF-17 (con't)
Staff Position All penetration seals between the diesel generator rooms and the auxiliary building should have 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire resistance.
Licensee's Response Investigation reveiled that all the penetrations are scaled.
Refer to new staff position PF-ll for response to existing penetration seals.
PF-18 Turbine Building, Fire Zone 69 & 70 - Hydrogen Seal Oil Units Curbs Staf f Concern The hydrogen seal oil units are located at the east and west ends of the tr '.ine building at the 695' elevation.
Each unit contains a significant quantity of lube oil and rupture of either unit may permit the spread of oil such that in the event of a lube oil fire the structural integrity of portions of the turbine building and the adjacent auxiliary building could have an adverse af fect on safety-related and safe shutdown syster -
Staff Position A curb should be provided around each hydrogen seal oil uni. of sufficient height to contain the entire contents of the unit plus a margin for fire suppression water.
Licensee's Response Employee access routes past the hydrogen seal oil unit would not allow a curb to be used (OSIIA).
Also, a curb arrangement would require some type of drainage piping installed. We feel the most reasonable solution is to extend the present drain trough around the. seal unit.
The new trough would be approximately 6" x 6" with a grating surface.
2-7
PF-19 Turbine Building, Fire Zone 69 & 70 - Lube 011 Reservoirs Staf f Concern The turbine lube oil reservoirs are located at the west and east ends of Fire Zones 69 and 70 respectively.
Each reservoir contains a large quantity of lube oil.
A fire at either reservoir could result in the loss of structural integrity of the turbine building.
Such a loss of turbine building structural integrity could have an adverse affect on safety-related and safe shutdown systems and components in adjacent areas.
Staff Position A.
Verify that the design density, coverage and nozzle locations of the Reservoir Fire Suppression Systems are adequate to suppress a fire involving rupture of the turbine lube oil reservoirs.
B.
Apply a U.L. listed fire retardant coating, suitable for protection of structural members, to the turbine building columns adjacent to the lubc oil reservoirs.
Licensee's Response A.
The deluge systems to the turbine oil reservoir, hydrogen seal oil units and annulus cable penetrations are design to conform with NFPA standard 15 with water densities of 0.30 gpm per square foot.
Hydralic calculations for this and other deluge and wet pipe systems are filed in our plant records.
B.
Several materials are being considered for the structural member coatings, one of which is Pyrocrete, a Carboline Co. UL listed product.
A suitable material will be applied.
P F-2 2 Cable Spreading & Relay Room - Safe Shutdown Equipment Staff Concern The cable spreading and relay room contains control and power circuits for systems normally used to shutdown the plant. Notwithstanding the provision for an alternate shutdown capability independent of the cable spreading and relay room, a fire in the room may cause sufficient damage to cabling to cause spurious actuation of equipment resulting in adverse effects on the safe shutdown capability of the plant.
2-8
i PF-22 (con't)
Staff Position Verify that a fire in the cable spreading and relay room would not cause the types of spurious movements of components that would adversely affect the ability to safcly shutdown the plant.
Licensee's Response In addition to the safe shutdown equipment identified in the January 2, 1979 response to Nrw Staff Position PF-12 spurious operation of the following valves may affect shutdown capability:
a.
Main Steam Isolation Valves b.
Feedwater Isolation Valves c.
Residual heat removal to letdown valves d.
Coincidental spurious operation of the pressurizer power operated reliefs with inoperability of their motorized isolation valves.
Portions of the control circuitry for each of these is in the relay room. Susceptibility of these circuits is being analyzed.
If analysis shows susceptibility, corrective measures will be taken.
PF-27 Piping Containing Flammable Gases Staff Concern One oxygen line (3/4") and one hydrogen line (l") pass from the gas house through the cast end of the turbine building into Fire Zones 58 and 73 in the auxiliary building. The hydrogen line is fitted with a high flow shutoff and the oxygen line which provides low volume, low pressure supply to the recombiner, has a manual emergency shutoff.
Fire Zones 58 and 73 contain safety related systems and equipment that may be required for shutdown in the event of a fire and a fire or explosion in these zones could damage systems needed for shutdown of the plant.
Staff Position Provide an analysis to demonstrate that the quantity of hydrogen or oxygen that could be leaked before detection and isolation of either gas line is not sufficient to jeopardize safety related systems and equipment needed to shutdown.
2-9
PF-27 (con't)
Licensee's Response H Analysis For Fire Zones 58, 73, 84, 2
59, and 74 A.
Zone 58 3
Max H feed rate through reg = 130 to / min SI Pump Area 1110 RHR Pump Area 675 Charge Pump 500 CC Pump JB@)
330 2
Gen Area (6-ll)(J-K) 2380 1190 2
Aux Bldg Sump Area 4785 2392 2
TOTAL AIR FLOW 6147 "2
2.1% non-explosive concentration
=
6147 + 130 (voluine)
B.
Zone 73 Aux Bldg Sump 2342 General Area 6-llK 1190 General Area ll-12K 3110 CC Pump 330 TOTAL AIR FLOW 6972
- "2 f" d 130 1.8% (by volume)
=
6972 30 2-10
PF-27 (con't)
C.
Fire Zone 84 Air flow 4710 ft / min 2.7%
% 11 feed
-4710 + 130 130
=
2 D.
Fire Zone 59 Air flow 4600 ft / min
%H f ed 130(ft / min) 2*8%
2
=
4600 + 130(ftJ/ min)
E.
Fire Zone 74 Air flow 6700 ft / min
%H f ed 130 1*9%
2
=
6700 + 130 2-11
PF-27 (con't)
Conclusion - H Analysis 2
An explosive mixture could be developed in the VCT room, but a f ailure of this tank would not jeopardize the ability to shut the plant down safely.
The H line passes through, or could affect, fire zones 58, 73, 84, 7
3/ min, and is thus 74, aHd 59.
The H regulator will pass 130 ft themaximumleakr$te.
The H is diluted by the aux Bldg air ventilation 2
system.
Calculations show that an explosive mixture would not occur in these zones.
Conclusion - 0 Analysis 2
The 0 regulator passes about 100 ft / min using the same dilution factors 2
as in the H, case, the 0 ncentration will rise in any given area 3% at 2
most.
It in our judgement that this will not jeopardize systems needed to shut the plant down.
PF-28 Diesel Fuel Oil Transfer System Staff Concern There are a number of areas in the plant in which are located diesel driven auxiliaries and their associated day tanks. Diesel oil is transferred to these day tanks from storage tanks located underground outside the main-plant.
The areas where these diesel driven auxiliarie-are locat2d are:
1.
The screenhouse (Fire Zone 41) contains two diesel driven cooling water pumps and a diesel driven fire prap.
2.
Fire Zones 25 and 26 each contain an emergency diesel generator.
The transfer piping for the diesel driven auxiliaries in the screenhouse enters the east wall of the building and runs along the ceiling across the area in which the electric driven fire pump is located. In the vicin-ity of the diesel driven fire pump two of the lines which provide diesel oil for the diesel driven cooling water pumps enter the upper level of the screenhouse and are piped to their respective day tanks. The remain-ing line is piped directly to the diesel driven fire pump day tank.
Diesel oil transfer piping for the emergency diesel generators is buried until it reaches the rooms in which the day tanks are located.
A fire fed by the day tank fuel supply could have serious consequences if provisions are not adequate to automatically or manually stop the transfer of diesel oil from the storage tank to the day tank in the event of a 2-12
PF-28 (con't) rupture of one of the fuel transfer lines or a fire at the day tank.
This is especially serious in the case of the fire pumps since the day tank for the diesel driven fire pump is located approx-imately 17 feet from the electric driven fire pump outlined in Item 4 of Enclosure 3, failure to cutoff the supply of diesel oil 'could result in an aggravated exposure fire.
Staff Position 1.
All diesel oil transfer piping that enters the screenhouse should be replaced with double jacketed pipe along its full length from its point of entry to the building to its termination at each day tank.
2.
A fusible link actuated shutoff valve should be provided in the diesel driven fire pump fuel transfer line at a point as close as possible to where the line enters the diesel driven fire pump day tank.
3.
Pre-fire plan strategies should be developed for all diesel fuel day tank areas to provide for tripping the diesel oil transfer pumps and/or isolating the fuel supply lines to the day tank in the event of a fire or a piping rupture.
Licensee's Response 1.
Several products have been reviewed for use as a pipe insulator, one of which is Pittsburgh Corning Foamglas. This material is UL listed
- R2844, has a flame spread of 5, fuel contributed of 25 and smoke developed of 0.
This material will provide adequate protection to oil piping and is practical to install. We propose the use of Foamglas or a similar material as an alternative to double piping.
263 A fusible link actuated valve would be slow in 're' acting. We feel the best approach is manual isolation by opening the pump breakers.
As suggested in the Staff Position 3, pre-fire plan strategies will be developed to provide tripping of the diesel oil transfer pumps.
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PF-30 Mechanical Penetration Seals and Fire Dampers Staff Concern A number of mechanical (piping, ventilation ducts and cable conduit) penetrations between fire zones are unsealed.
Dampers are not provided in most vet.t ducts where the ducts penetrate fire barriers.
These unsealed penetrations and open ducts could provide a path for the spread of fire, smoke, and hot gases from one fire zone to another. The consequences of fire damage in two or more fire zones, has not been deter-mined.
In addition, the spread of fire to other zones would increase the difficulty in manually fighting a fire. The potential for spread of fire, smoke and hot gases could result in additional requirements for fire bri-gade personnel above that recommended in staff position PF-7.
Staff Position The mechanical penetration seals and ventilation dampers in fire barriers should be upgraded as indicated below:
1.
Fire Zones 8, 9, 14, 69 and 70 at the boundaries of these zones and the Auxiliary Building - Fire dampers and mechanical penetration seals having a three hour rating.
2.
Fire Zenes 12,15, and 83 - Fire dampers and mechanical penetration seals of a rating equivalent to the combustible loading in each zone.
3.
Fire Zones 13, 18, 18A, 19, 31, 32, 61 and 66 - Fire dampers and mechanical penetration seals having a three hour fire rating.
4.
Fire Zones 33, 34, 35, 36, 80 and 81 - Fire dampers and mechanical penetration seals having a three hour fire rating at the zone bounda-ries contiguona with the turbine building.
5.
Fire Zones 37 and 38 - Fire dampers and mechanical penetration seals having a three hour fire rating at the zone bouadaries.ontiguous with the turbine building and with Fire Zone 24.
6.
Fire Zones 58 and 73 - Mechanical penetration seals between charging pump cubicles o' a rating equivalent to the combustible loading in each cubicle.
7.
Fire Zone 68 and 72 - Mechanical penetration seals having a fire rating of three hours at the boundaries between each zone and the Auxiliary Building.
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PF-30 (con't)
Licensee's Response 1.
A review of each penetration in zones 8, 9, 14, 69 and 70 has been completed.
Several were found with open paths between zor.es, many others werd questionable. We agree to re-examine each penetration and up-grade those seals that are found deficient.
Material will coaform to products listed in PF-ll or equivalent.
Two ventilation duct penetrations were found in zone 70 to the Auxiliary Building. These ducts will be fitted with approved dampers.
2.
No pipe or conduit was found with open paths. We agree to inspect each penetration and upgrade seal as needed.
Each of the zones have walls penetrated by ventilation ducts.
Ducts into the access control rcom will be fitted with approved dampers.
Ducts penetrating the records and I6C room walls are small (4" x 8" or 5" diameter) and penetrate into areas containing no safeguard or safe shutdown equipment.
These openings do not prescat a serious fire threat.
S.
Comments in Item 2 above apply for pipe and conduit.
The Control Room ceiling is penetrated by the supply and return air ducts. This equipment is rated QA Type I.
We feel the addition of a Type III damper in QA Type I systems is not justified.
There is very little combustible material in the zone above the Control Room.
Ventilation ducts affecting zones 18, 19, 31 and 32 will be fitted with r pproved dampers as referred to in comments to Item 4.
4.
In this group of zones, no pipe or conduit penetrations were found to be deficient.
When the plant was constructed fire dampers were installed in the ducts for Unit ! only. To correct this situation a study of ducts and vents was made and a list canpiled of deficient penetrations for both units. A purchase order has been written to <esign, supply, and install fire dampers.
A problem encountered at. tat time was the rating and designation between fire dampers and fire doors.
The suppliers we talked with could not supply 3-hour fire dampers. To get the 3-hour rating, a fire door was necessary.
Review of the installed duct work showed the doors could not physically be installed in the required locations.
Review of codes and discussion with American Nuclear Insurers lead us to a solution using two 1 1/2-hour rated fire dampecs.
One damper would be installed on either side of the wall.
2-15
PF-30 (con't)
We feel this is an adequate solution and will implement this fix where 3-hour dampers cannot be obtained or are unsuitable.
5.
No deficient pipe or conduit penetrations were found. The walls are penetrated by scaled bus ducts, and the battery room exhaust fan duct.
The air duct has or will have (Item 4) dampers at the wall into the battery rooms. The location of the penetration in the turbine room contains very little combustibles and the 480 normal switchgear ruom contains no power supply to safeguard or safe shutdown equipment.
For these reasons we do not feel the installation of a damper is necessary.
6.
The charging pump cubicles were found to have many unsealed pipe penetrations between the rooms. We agr.e to seal all openings with a approved material. No ventilation ducts penetrate these rooms.
7.
All cable, pipe and conduit penetration of the shield building have seals.
The annulus vertilation duct penetrations are located in upper levels of Auxiliary Building where very little combustibles (cable) are installed.
The annulus in the area of the penetration contains no conbustibles.
In addition, each ventilation duct contains three isolation dampers although not rated for fire dut:*.
For these reasons we do not plan to install additional dampers in these ventilation ducts.
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