ML19263D636
| ML19263D636 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/19/1979 |
| From: | Reid R Office of Nuclear Reactor Regulation |
| To: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7904130094 | |
| Download: ML19263D636 (17) | |
Text
~72!4A f " " ' %',,
3 UNITED STATES f
NUCLEAR REGULATORY COMMisslON
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"e W ASHINGTON, D. C. 20555 Q]4)j March 19, 1979 Docket Nos. 50-317 and 50-318 Mr. A. E. Lundvall, Jr.
Vice President - Supply Baltimore Gas & Electric Company P. O. Box 1475 Baltimore, Maryland 21203
Dear Mr. Lundvall:
As a result of our continuing review of the fire protection program for Calvert Cliffs Nuclear Power Plant Units Nos.1 and 2, including our site visit, we find that the additional msponses as requested in the enclosures are required to continue our review. Enclosure 1 contains our evaluation of your October 20, 1978 response on Staff Positions 1 through 8.
formally documents the Staff Positions 9 through 22 ' hat were discussed at our December 1,1978 Fire Protection Review exit meeting.
We request that you provide the additional responses as indicated in the enclosures within 30 days of the date of this letter.
Sincerely.
. /v/. w
. W. Reid, Chief Operating Reactors Branch #4
Enclosures:
As stated cc: See next page 7 9 0 413 00Vl i
i t
Saltinore 3as L Elec ric Company cc:
Jar.es A. Sidcison, Jr.
Mr. R. M. Douglass, Manager General Counsel Quality Assurance Department G and E Builcing Room 923 Gas & Electric Building Charles Center P. O. Box 1475 Bal timore, Maryland 21203 Baltimore, Maryland 21203 George F. Troweridge, Esquire Shaw, Pittnan, Potts and Troweridoe 1800 M Street, M.U.
Washington, D. C.
20036 Mr. R. C. L. Ol son aaltinore Gas and Electric Company Room 922 - G and E Building Post Office Box 1475 Bal tinore, Maryland 21203 Mr. Leon B. Russell, Chief Engineer Calvert Cliffs Huclear Power Plant Baltinore Gas and Electric Company LusDy, Maryland 20657 Bechtel Power Corporation ATTH:
Mr. J. C. Judd Chief Nuclear Engineer 15740 Shady Grove Road Gaithersburg, Maryland 20760 Canbustion Engineering, Inc.
ATTH:
Mr. P. W. Kruse, Manager Engineering Services Post Of fice Box 500 Windsor, Connecticut 06095 Calvert County Libra y Prince Frederick, Maryland 20678 e
e
Calvert Cliffs Nuclear Power Plant Fire Protection Review Staff Positions 1 Through 8 This enclosure documents the status of the first eight positions that BG&E responded to by letter dated October 20, 1978.
" Resolution" or
" Action Requested" is indicated for each staff position.
P-1.
FIRE 000R SUPERVISION.
Staff Position Fire door should be normally closed and locked or electrically super-vised with delayed alarm annunciation in a constantly occupied area.
Evaluation The BG&E response states that fire doors are normally closed, locked or monitored b.y the p' ant security system. The response does not provide assurance that fire doors which are not locked or electrically super-vised will be ktpt closed.
Action Requested BG&E agreed to provide additional information which identifies the doors which are not locked or electrically supervised and the fire hazards on both sides of such doors. Justification for not having these doors locked or electrically supervised should also be provided.
P-2.
ELECTRICAL CABLE PENETRATION QUALIFICATION Staff Position The cable penetration fire barriers should be tested to demonstrate a three-hour rating, as is. required for fire barriers.
The test should br performed or witnessed by a representative of a qualified independent testing laboratory.
The tests should be performed in accordance with ASTM E-119 and the following conditions:
(1) The cables used in the test should incluue the cable insulation materials used in the facility.
(2)
The test sample should be representative of the worst. case configu-ration of cable loading, cable tray arrangements, anchoring and penetration fire barrier size and design.
The test sample should also be representative of the cable si:es in the facility.
Tes ting of the penetration fire barrier in the floor configuration will cualify the fire stop for use in the wall configuration also
2 (3) Cables penetrating the fire barrier should extend at leas ~t three feet on.the unexposed side and at least one foot on the exposed side.
(4)
The fire barrier should be tested in both directions unless the fire barrier is symmetrical.
(5)
The fire barrier should be tested with a pressure differential across it that is equivalent to the maximum pressure differential a fire barrier in the plant is expected to experience.
(6) The temperature levels of the cable insulation, cable conductor, cable tray, conduit, and fire stop material should be recorded for the unexposed side of the fire barrier.
(7)
Acceptance Criteria - The test is successful if:
(a)
The cable penetration fire barrier has withstood the fire endurance test without passage of flame or igni-tion of cables on the unexposed side for a period of three hours, and (b)
The temperature levels recorded for the unexposed side are analyzed and demonstrate that the maximum temperature is sufficiently below the cable insulation ignition temperature, and (c) The fire barrier remains intact and does not allow projection of water beycnd the unexpcse: surface during the hose stream test.
If previous tests can be shown to meet the above pcsition, -he ti:e see should provide the results of the tests to show that the above ;osi-ion is met.
. Evalua tion BG&E takes exception to this requirement for testing the cable pene-trations. They provided the sketches of the penetration designs and contended that various components in the designs have been success-fully tested and the design was approved and accepted by NELPIA.
The information provided is not sufficient to establish the fire resistance rating of the penetration.
It did not describe the tests, the results or the extent of NELPIA's review.
Action Requested BG&E is requested to prnvide additional information concerning the tests and NELPIA's docenentation that is sufficient to establish the fire rating of the penetrations.
P-3.
SELF-CONTAINED BREATHING APPARATUS Staff Position Ten self-contained breathing apparatus should be provided. Each self-contained breathing unit should be provided with two spare bottles and six hours onsite reserve of air.
Evaluation BG&E states that the prescribed equipment has been provided. The staff has verified and accepted the licensee's provision of self-contained breathing apparatus.
Action Recuested _
Nore, item is resolved.
P-4.
FIRE WATER VALVE SUPERVISION Staff Position All valves in the fire water systems should be either elect-ically super-vised, or Iccked in :r::er csition or previded wi.- s ar:ar :r::'
seal, and administrat vely c:ntrolled.
i Evaluation SG&E says that the main OS&Y valves in the fire protection systems are electrically supervised. Water storage tank isolation valves and sec-tional valves in the yard fire main are locked open.
The staff has verified and accepted the licensee's method of water valve supervision.
. Action Recuested None, item is~ resolved. ~ ~ --
~
P-5.
RCS PUMP LUBE OIL COLLECTION SYSTEM Staff Desition Each reactor coolant pump should be provided with an oil collection system to contain lube oil leakage and drain the leaked oil to a safe place.
Evaluation BG&E has said that the RCS pumps have been equipped with an oil collection system. The information provided is not sufficient to permit an evaluation of the collection system.
Action Requested BG&E agreed to provide sketches and a description of the RCS pump lube oil collection system.
P-6.
FIRE DETECTOR IN CONTROL ROOM CABINETS AND CONSOLES Staff Position Each of safety-related cabinets and consoles in the centrol room should be provided with a fire detector.
Evaluation BG&E responds that the control roo.a cabinets and consoles are open at the top and that detectors have been strategically provided at the top.
The staff accepts this design.
Action Recuested None, item is-resolved.
P-7.
BATTERV ROOM VENTILATION AIR FLOW MONIT00 Staff Position A ventilation air ficw menitor should be installed in each of the station battery rocms to alarm and annunciate, in the control roca, the 1 css of the ventilation air ficw.
. Evaluation BG&E does not accept this position on the ground that the venti-lation system consists of two fans (one supply and one discharge as verified in the exit meeting) with independent power supplies anc that hydrogen are only generated during occasional high-charging periods which are supervised.
The BCaE response does not include sufficient infonnation; (1) to substantiate their. contention that two fans, one supply and one discharge, do provide redundancy for the battery rooms ventilation system; (2) describing the method of supervision to be provided.
There is no indication to alert the operator of the interruption of ventilation air flow and the sabsequent hydrogen buildup if a damper in the ventilation system were to close inadvertently. Hydrogen generation is not limited to the high-charging periods and hydrogen buildup cannot be detected by physical senses of the human being.
Action Requested BG&E is requested to provide the air flow monitor for the battery rooms as indicated in our staff position.
P-8.*
CABLE SPREADING ROOM PROTECTION Staff Position In addition to detection and manual suppression capabilities:
(1) An automatic fire suppression system should be installed in the cable spreading room, and (2) Shutdown capability independent of cabling and equipment in the cable spreading room enould be provided unless it can be demonstrated that at least one division of cabling and equipment can be preserved for safe shutdown during and following a major fire.
- This position combines previous positions P-8 and P-14.
. Evaluation There are two cable spreading rooms in the plant; one for each unit.
Each cable spreading room contains, in addition to redundant safety and shutdown system cables, both divisions of safety-related electrical equipment cabinets that are e sceptible to heat and water damage. The minimum separation between cable trays from redundant divisions is about 9" vertically and essentially nothing horizontally because trays from redundant divisions cross eacn other in several instances.
In these cases, Marinite boards, flush with the width of the try, are provided at the top and the bottom of tray
- of one division until they are approximately 3' away from trays r the other division.
Conduits of redundant divisions are routed to within a couple Df inches of each other, or of trays, in many places.
Trays are generally stacked 5
-6 trays deep. The access for manual fire fighting is fair, each cable spreading room has one access from outside in addition to the intert.onnecting doorway between the two rooms.
Smoke' detectors and portable extinguishers are provided to protect cabling in the room while total flooding Halon 1301 systems, actuated automatically by heat detectors protect electrical equipment cabinets in the room. A manual hose station is available from outside the rooms; however, it has not been demonstrated that the existing hose can effectively reach every point in the rooms. The licensee indicated that he does not favor using water to suppress a fire in the room. Effectiveness of portable extinguishers in fighting a major fire is not demonstrated.
The existing detection and manual fire fighting system may not be adequate to ensure that atileast one division of cables and equipment can.be preserved for safe shutdown in the event of a fire in these rooms.
BG&E does not accent the cosition that autoratic # ire suppression syster.s should be installed in the rcom on the grounds tnat the superior fire resistance of the silicone rubber insulated cabies have been verified by their own tests.
Silicone rubber insulated, asbestos jacketed cables are used for instrumentation, control and small power application. All medium and large power applications use cables insulated with conventional materials such as cross-linked polyethylene, ethylene proplyene rubber and hypalon. Flame propagation tests were conducted in the process of selecting such cables for these services. The procedures and the results of the tests were summarized in the paper titled,
" Flame Propagation Tests on 600 volt Control and Power Cables in Trays for Calvert Cliffs Nuclear Power Plant" which was submitted to IEEE International Symposium on January 28, 1971. This paper was referenced in page 0-29 of the licensee's submittal, "The Fire Protection Program Evaluation."
. The flame propagation tests were conducted on a single tray and a horizontal stacked tray (2 trays) configurations which include an 8' horizontal section with a 4' vertical section on each end.
Each tray was loaded with on.e layer of test cables, one-hal f diameter apart and subjected to 5 minute exposure to transil oil fire in a 5 gallon open-top can.
" Circuit integrity" was indicated by measuring ieakage currents in open circuits.
Among the major test conclusions are:
1.
Silicone ruboer cables can maintain the " circuit integrity",
provided no water spray was applied, under the fire condition for 40 minutes or more when energized with 120V circuit fused for one ampere.
2.
Silicone rubber burns but produces less visible smoke.
3.
Under the test condition (maximum of 2 tray stacking, one layer cable fill, 5 minute exposure) silicone rubber cables exhibited a limited flame propagation and self-extinguished 20-25 minutes after the ignition source was removed.
4 Metal corduits deiayed, but could not prevent failure of contained cables.
5.
With pro;,erly applied flame retardant coating, the cable fire self-extinguished under the test conditions as soon as the fire source was remoyed while the uncoated silicone rubber cable fires generally lasted 20-25 minutes af ter the ignition source was removed.
The licensee cites these test results as justification for taking exceptions to guidelines of Appendix A to BTP 9.5-1.
The staff has reviewed the report cited above and concludes that these tests results alone do not provide adequate justification for taking such exceptions.
For example:
1.
Section F.3.(a).1 of Appendix A to BTP 9.5-1 provides: "The primary fire suppression in the cable spreading room should -
be an automatic water system".
The licensee contends that automatic water systems are not necessary because safe shutdown of the plant is assured by the capability of silicone rubber cables to maintain the " circuit integrity" during and following a fire and because the cables are difficult to ignite, slow to propagate fire and self-extinguishing in the absence of an igc.ition source.
8 The staff concludes that while these statements may be true for the test configuration they may not be true for the actual configu ration.
In the configuration observed in the CCNPP cable spreading room, a large concentration of cables presents in a confined space (s tacks of 5-6 trays, less than one foot between trays, up to and exceeding 100% tray fill). A fire involving cables in such a confi-guration is likely to be prolonged and sustained because of a heat energy feedback to the fire that is higher than that of the test con figura tion.
The licensee's tests do not establish that such a cable fire would self-extinguish.
While the tests showed that when silicone rubber cables are exposed to a fire, leakage current in open circuits is less than 1 ampere at 120 volts they do not dcmonstrate that silicone rubber cables involved in a fire are capable of actually carrying loads required by their functions for an extended period of time during and following a fire. Moreover, the rooms also contain some conventional cables that are susceptible to fire damage.
The licensee's contention that the circuit integrity can be maintained to preserve the safe shutdown capability in the event of a fire in the cable spreading room, therefc e, carnc be substantiated.
Furthermore, the licensee has not shv :ha t 9e rcs casualty crocedures that benefit from such circu't ccn ir.it.
or how fire fightihg effort would be affected by suc :rcc d. es.
The cabit..preading rooms also contain electrical equipment which are susceptible to heat and water damage. The licensee has not evaluatec the effects of a fire or fire fighting activities on such equipment.
It has not been demonstrated that the plant can be safely shut down without these equipment.
2.
Section F.3.(a).3 of Appendix A to BTP 9.5-1 provides:
"Each cable spreading room should have divisional cable separation by 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire wall.
For cable spreading room that do not provide divisional cable separation by 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire wall.
all cables should b: coated with a fire retardant coating and adequate divisional cable separation should be provided."
The licensee contends that the silicone rubber cables are covered with glass. braid and asbestos jacket which by design has a fire retardant coating (asbestos). An additional fire retardant coating is, therefore, not required.
The staff concludes that based on the licensee's tests, the asbestos jacket is not equivalent to retardant coating. The licenser has not evaluated the effects of non-silicone rubber cables which are in the cable spreading mom on flame propagation.
_g.
Divisional separation of cables in trays and in conduits were discussed in the " Staff Concern".
The licensee contends that the separation is adequate. The staff concludes that the licensee has not provided adequate evidence to justify his contention that at least one division of safety-related cables can be preserved for safe shutdown in a room with the above described configuration when the effects of a fire or fire fighting activities, including a possible spray of fire water, are taken into account.
Action Requested BG&E is requested to provide:
(1) an automatic fire suppression system in the cable spreading room; and (2) an alternate shutdown capability independent of the cabling and equipment in the cable spreading room.
CALVERT CLIFFS NUCLEAR POWER PLANT FIRE PROTECTION REVIFW STAFF POSITIONS 9 THROUGH 22 This enclosure documents the staff position discussed with BG&E at the December 1, 1978, Fire Protection Review exit meeting. BG&E is requested to document their response'to each staff position.
P-9.
Seraration Criteria STAFF CONCERN The tests, as referred in the licensee's submittal, " Fire Protection Program Evaluation", dated March 1977, which were performed during the process of selecting silicene rubber insulated, asbestos jacketed cables to be used at Calvert Cliffs Nuclear Power Plant (CCNFP) do not represent actual configurations of tray loading and raceway arrangement generally observed in the plant. In addition, silicene rubber cables are used only for instrumentation, centrol and small power application.
Cables insulated with cross-linked polyethylene, ethylene proplyene rubber, and hypalon are used for larger power applica-tien. The staff, therefore, is unable to conclude that cables used in CCNPP ccmbined with the separation provided at the plant provide adequate protection in the event of an unmitigated fire.
STAFF POSITION Provide the results of tests or analysis to demonstrate the effectiveness of CCNPP cables, in the configuration found at the plant, in preventing simultaneous loss of function to redundant divisions of cables required for shutdown from an exposure fire; or provide modifications necessary to preserve the opera-bility of at least ene division of systems required for safe shutdown.
P-10.
Cable In Cenduit STAFF CCNCERN The infor=ation provided in Section 8 5 5.h of Calvert Cliffs FSAR Rev. 5/3/73 and the cbservations during the site visit revealed that no separation criteria have been established for the routing of conduits containing sefety related cable.
STAFF POSITICN 1.
Provide the results of test or analysis to demenstrate that the asbestos jacketed silicene rubber cable routed in conduit will maintain its function during and follcwirg a fire.
. Forothertypesofinsulated(safety-related)4 cables 2.
routed in conduit within a fire area additional protection should be provided unless it can be demonstrated that the loss of such cables will not produce adverse effects on the shutdown capability of the plant or result in excessive radioactivity release.
P-11.
Fira Hazards Analysis STAFF CCNCETdl The licensee's analysis, dated March 15, 1977, has not provided sufficient infomation for the staff to conclude that the capability to safely shutdown the plant will be preserved in the event of a major fire.
STAFF POSITION Provide an analysis which will demonstrate that a safe shutdown capability will be maintained, and excessive radioactivity release will not result, in the event of a major fire in any area of the plant. The size of the postulated fire should be based on the combustibles in the area and a @"
amount of transient combustible that may be reasonably expected to be brought into or moved through the areas for maintenance and routine operation. The analysis should include the following
' consideration:
1.
Ioss of offsite power simultaneous with the fire, 2.
Damage to cabling and equipment resulting frem the fire water application and from other fire fighting related activities, 3
Spurious system transients resulting from fire induced faulting of. electrical cables.
L Effects of smoke and heat building up within the fire area and their propagation via unsealed cpenings and penetrations in barriers, 5
Where assu=ptions are made as to the operability of cables orequipmentduringand/orfollowingthepostulated fire such assu=ptiens should be demonstrated by tests and/cr verified by analyses.
Where it cannot be shown that a safe shutdown capability exists Safety-related systems are systems serving those functions as identified in Regulato:7 Guide 1.29.
. during and following the postulated fire, the licensee shall propose appropriate modifications such as an alternate shutdown capability or barriers to protect the equipn:ent. Additional suppression in lieu of barriers may be considered en a case b case basis.
/
P-12.
Detection STAFF CONCERN During the site visit it was observed that many safety related areas are not provided with automatic fire detection. Therefore, a fire in these areas may not be promptly detected.
STAFF POSITIGI Fire detection should be provided in all areas which contain redundant division of safety related cables and/or coc:ponents.
P-13 Fire Hose Coversee STAFF CQ1CEPJJ During the site visit it was observed that many plant areas are beyond the reach of presently provided interior hose.
STAFF POSITION Hose stretch tests should be perfomed and additional interior hose or hose station provided as necessary to ensure that all points in each safety related area and area containing large fire ha::ards which may expose safety-related equipment can be reached by at least one effective hose stream. The length of the hose at each station should be lind.ted to 100 feet maximum.
P-14.
Cembined with P-8.
P-15 Ccemunication STAFF CCN 3 1 A fire at the common electrical penetratien contairdng both normalsoundpoweredandpage/partysystemscoulddisable both communication systems into the containment.
STAFF POSITICN These two systems should be separated in such a manner that a single fire will not disable both com=unication systems into the containment.
. F-16.
Valve Identification STAFF CCNCERN P.I.V.'s and control valves for Fire Suppression Systems should be easily identified to permit rapid control for the Fire Suppression Systems in the event of need due to failure or fire control requirements.
STAFF POSITIQi Provide identification tags, stencils, labels or appropriate signs, on the valve that will allow for the ready identification of each.of the valves control area without need for reference to written descriptions or reference numbers.
P-17.
Manual Fira Flahtine Ecuirment STAFF CCNCERN Manual fire fighting is either the primary or the secondary fire suppression system for many areas of the plant and requires adequate fire fighting equipment to effectively carry out the functions of fire fighting.
STAFF POSITIQi Provide the following additional equipment for each exterior hose cabinet; 200' - 2 1/2" hose (single jacket-lined-s one(1)21/2"x11/2"x11/2"gatedwye;one(1)21/ynthetic);
2" combinationfog/(1)11/2" fog /straightstreamnozzlerated straight stream nozzle rated at 250 GFM (ormore);one at 60-$O GFM; 2 each of 21/2" and 11/2" hose gaskets.
All hoses, 21/2" and 11/2" stored in the exterior hose cabinets should be stored in donut rolls.
All exterior hose cabinets should be cleaned and equipment contained therein should be maintained in proper working order at all times.
Interior standpipe hose stations should be provided with one (1) universal type hose spanner that can be used as a hose valve wrench and as a hose coupling spanner for both 21/2" and 11/2" hose.
Additional fire fighting equipment to be provided in each portable fire equipment cabinet includes the following:
50' - 2 1/2" Fire Hose 1 - Hallig/2" Fire Hose an type forcible entry tool ICO' - 1 1
~5-Fire fighting equipment that should be cunided at a suitable central location should include: one (^1) heat sensing device; ten (10) sets of fire fighting protective clothing i.e. - 10 (ten)firefightinghelmets;10turnoutcoatsw/removableliner; 10 pair fire fighting boots; 10 pair gloves.
Provide proper saniti::ing solution for the saniti::ation of self-contained breathing apparatus face masks.
Relocate the self-contained breathing apparatus recharging system frem the present location in warehouse #1 to a suitable central location within the Unit 1 - Unit 2 cperating areas.
Provide a cooling water tank for each cascade system for air cylinders being recharged.
F-18.
Emereenev Lichtirg STAFF CCNCERN Many of the fixed sealed beam emergency lighting units were observed to have a rating of only 11/2 hours as compared to the 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> rating prescribed by appendix A to BTP9 5-1.
STAFF POSITICN Fixed sealed beam lighting units should be providad to facilitate access for fire fighting, egress, and emergency operation of equipment in safety related areas. Each lighting unit should have a rating of at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
P-19.
Fira Pt e Seearation STAFF CCNCERN Redundant fire pu=ps as well as diesel day tank are located in the scoe room and are subject to damage frem a single fire in the m house.
STAF PCSI"ICN
~
A three-hour rated fire barrier should be provided to separate the redundant fire water pu=ps so that the availability of at least one fire water m can be assured in the event of a fire in the pu=c house.
F-20.
Fire Water Usace STAE CCNCE:2; 3.e licensee's Fire Protecticn P:cgrsm Ivaluatien, dated March, 1977 (page 3-12), stated that when water stored in fire
. water tanks is used for services other than fire protection it will be drawn through the intemal standpipe thereby assuring that the + 4 mum of 300,000 gallons per tank will be reserved for fire protecticn. However, during the site visit it was observed, contrary to +he above statement,that fire water drawn through the fire pu.*.ps was used for unidentified purposes other than fire protection.
STAFF POSITION (1) Fire water should be physically dedicated for fire use.
Use of water stored in the tenks for services other than fire protection should be limited to that drtwn through the internal standpipe without usinE the fit : pumps.
or (2) Identify all other uses (including purpose, ilow rate, consumption etc.) of fire water and provide the results of an analysis to demonstrate that such uses will have no adverse effects on the availability of water for fire use.
P-21.
Control of Cembustibles STAFF CONCEPR Excessive combustible materials were observed in some plant areas, posing unnecessary fire hazards.
STAFF PCSITION Combustible materials which are not required for routine plant operational and maintenance activities should be removed from the safety related areas. Storage of combustible materials in safety related areas which are needed for plant operational and maintentance should be restricted to approximately one week's supply. Storage of combustible materials in the close croximity ordirectlyundersafetyrelatedcablingorccieponents{e.g., hot machine shop and nearby hallway) should be prohibited.
P-22.
Fire Water Svstam Overtressura STAFT CCNCEPS During the site visit, steady pressures of up to 275 psig were observed in the sprinkler systems in the turbine building, the fire pu=p house, and elsewhere. Fire pc-o shut-off head as confirmed by the licensee is 175 psig.
The cause of such abnormally high pressure in ti fire water system is unknown; it cannot be produced by the fira pump.
Such overpressurization could be detrimental to the fire water system.
STAF7 POSIICN Ihe cause of overpressurization should be identified and corrected unless it can be demonstrated that the cause and consequences of such overpressurization are not detrimental to the fire water system or to the plant safety.