ML13317B138
| ML13317B138 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/29/1982 |
| From: | Krieger R Southern California Edison Co |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-03-04.C, TASK-3-4.C, TASK-RR NUDOCS 8205050155 | |
| Download: ML13317B138 (33) | |
Text
Southern California Edison Company PO. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 April 29, 1982 Director, Office of Nuclear Reactor Regulation Attention:
D. M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
Subject:
Docket No. 50-206 SEP Topic III-4.C San Onofre Nuclear Generating Station Unit 1 Enclosed is the draft assessment for SEP Topic III-4.C, Internally Generated Missiles. If you have any questions on this draft topic assessment or require additional information, please let me know.
Very truly yours, R. W. Krieger Supervising Engineer, San Onofre Unit 1 Licensing Enclosure A00 8205050155 820429 PPDRADOCK 05000206
~'PDR
DRAFT ASSESSMENT OF-.
SEP TOPIC III-4. C INTERNALLY GENERATED MISSILES SAN ONOFRE NUCLEAR GENERATING STATION.
UNIT 1
I.
INTRODUCTION Missiles that are generated internally to the reactor facility(inside or outside containment) may lead to, damage of structures, systems,and components that are necessary for the safe shutdown of:the'reactor facility or accident mitigation and to.the structures,. sjystems and components whose failure could result in a significant release.of radioactivity. The.sources of such 'missiles are valve bonnets and hardware retaining~bolts, relief valve.parts and'.instrument wells,
'pressuree containing equipient such as. accumulators and high pressure bottles, high speed rotating machinery, and rotating segments (e.g.
impellers and fan -blades).,"
Scope of Review The scope of the review is as outlined in the Standard Review Plan (SRP)
Section 3.5.1.1,."Internally Generated* Missiles (Outside Containment),"
and SRP Section 3.5..1..2,. "Internally Generated Missiles (Inside Containment).-"* The review specifically excludes SRP Section 3.6.1, "Plant Design for Protection Against Postulated Piping Failures. in Fluid Systems Outside.Containmeht, " 3.6.2, "Deterriination of Break Locations and Dynamic Effects Associated with the Postulated Rupture of Piping, "
as well.as those SRP sections dea'lin'g with natural phenomena (including.
missiles generated by natural phenomena), missiles. generated outside the fa6ility,: and turbine missiles.
REVIEW CRITERIA..'
The acceptability of the'design ofrrotection of facility structures, systems, and componentsifrom internally generated missiTes is based on meeting the following: criteria:
- 1.
General Design Criterion 4, with respect.to protecting structures, systems and components against the effects of iiternally generated mi'ssiles to maintain.their essential safety functions.
- 2.
Regulatory Guide 1.13, as related to the spent fuel pool systems and.structures being capable of, withstanding the effects of internally generated missiles and preventing missiles from imp'actin'g stored :fuel as semblies.
- 3.
Regulatory Guide 1.27, as related to the ultimate-heat sink and
- .connetin nd'ts b' capdble of nnecing ng capable of wistan ing the effects of internally generated missiles.
In addition,. the following.specific criteria are used in this evaluation:
- 1.
Safe shutdown is assurhed to be cold shutdown.
2..
No single failure "in addition to the missile and its consequences is assumed.
- 3.
Except where specifically discussed, when equipment is struck by a missile, failure of the eqtuipment. is assumed. This is based on failure of the equipment itself or on failure of. auxiliary equipment, such as switches, power supplies, pipe supports or other related equipment. -
-2 III.
RELATED SAFETY TOPICS, AND INTERFACES
-Review Areas Outside the Scope of this Topic As stated previously,"this review specifically excludes the following:
- 1.
SRP Section 3.6.1, "Plant Design for Piotection Against Postulated Piping Failure in Fluid Systems Outside Containment" -
This matter willbecovered under SEP topic III-5.B, "Piping"Break Outside Containment. "
- 2.
SRP.Section 3 6.2, "Determination of Break Locations and Dynamic Effects Associated with the P.ostulated ifupture of Piping" -
This matter will be covered under. SEP topic III-5.A "Effects.of Pipe.
Break on Structures, Systenis and Components Inside Containment."
- 3.
Natural'. Phenomena.-
This matter will be covered under SEP topic 111-6, "Seismic Design Considerations" and III-4.A, "Tornado.
Missiles."
- 4.
This matte'r will be covered under SEP topic III-4.B, "Turbine Missiles."
Interfaces with Other.SEP Safety Topics Satisfactory resolution of the following SEP'topics will depend, at least in' part,. on satisfactory resolution of this topic:
- 1.
Topic VII-3 "Systems Required for Safe Shutdown"
- 2. 'Topic V-II-4 Effects of Failure in 'Non-Safety Related Systems on Selected Engineered Safety Features"
- 3.
Topic IX-1 "Fuel Storage"
- o.
Tpic IX-3. "Station Service and Cooling Water System"
- 5.
Topic II-3.C "Safety Related Water Supply"' (Ultimate Heat'Sink)
'IV.
REVIEW GUIDELINES
- 1. 'Systems and.components needed to performsafety functions were identified 's those.listed in SRP Section 3.2'2, "System Quality Group Classification"..
Systems needed to perform safety functions:
- a.
Reactor Coolant stem
- b.
Chemical and Volume Control System (portfons)
-3
- c.
Auxiliary Coolant System
- d.
Safety Injection System
- e.
Main Steam System (portions)
- f.
Circulating Water System (portions)
Miscellaneous Water System (portions)
- h.
Feedwater and Condensate Systems (portions).
i..-
Compressed Air System
- j.
Air Conditioning System (portions)
- k.
Diesel Generator System
- 1.
Auxiliary Feedwater System
- 2.
Systems whose failure may result in release of unacceptable amounts of radioactivity:.
- a.
Reactor Cycle Sampling. System
- b.
Radioactive Waste Disposal Systems
- c.
Air Conditioning System
- d.
Auxiliary Coolant System (portions)
- 3.
Electrical systems which are necessary to support those fluid systems needed to.perform safety functions are:
- a.
4 16P-Volt System (See' item 1.k for-Dies&I Generators)
- b.
480-Volt System c..;
125-Volt DC System
- d.
120-Volt AC System Additionally, the control room was evaluated because of its importance to safety.
4 V.
REVIEW AND EVALUATION' V,1.:
Systems needed to perform safety functions:
V.1..a.
Reactor Coolant System The reactor-coolant system serves as the pressure retaining boundary for the primary coolant.
The system is comprised of; a reactor pressure vessel and three parallel heat.transfer loops. yEach loop contains one steam generator, one pump, connecting piping and instrumentation.: The pressurizer and associated, relief"'and safety valves are connected by the surge and spray lines to two of the reactor coolant lines. <The purpo.se df the pressurizer is to maintain primary coolant pressure and compensate for coolant volume changes as the. heat load'changes.
All components of. the primary, coolant system are located withiri the-containment building.I Overpressure protection is.provided to assure.that the coolant system pressure does not exceed design;limits.
The reactor vessel is enclosed in a concrete shield with a removable concrete cover and it is therefore coricluded that the vessel will not be affected by missiles outside the shield. There are no potential sources of missiles which could.affect.th.e vessel within the shield. -This shield will also prevent any missiles origirfating frri the reactor 'vessel from affecting other components. The control" rod drive mechanisms are-mounted on the top of the reactor vessel and are considered as 'an extension of the reactor vessel head.
Because of thi's design, we do not consider the drive mechanisms as likely-missiles. The concrete cover :is further protection against potential missile damage to safety systems.
Th pressurizer is enclosed with steam'generator B in a
'concrete shield with a removable concrete' cover and is therefore uifikel'y to:be affected by missiles o'utside the shield. This shield will also prevent any missiles originating from the pressurizer '(primarily the relief valves at the top
'ofthe pressurrizer.from affecting: component's outside the steam.generator B compartment.'
The most likely trajectory for missiles from pressurizer relief valves is vertical.
Since thepressurizeris next'to steam generator B, it 'is unlikely that any such missiles will affect steam generator B.
The possibility that missiles may result fom destructive
'overspeeding of one of the'primary c'oolaht pumps was also examined.
-,It was concluded that potentially damaging impeller missile ejection from' the broken pipe is minimized by a massive steel pump casing.> 'Ge'eration of niissiles from
-5 overspeed of the motor, flywheel, and the impeller is a generic issue'.which-is being reviewed under Task Action:Plan B-68, "Pump Overspeed During a LOCA" The steam geneIators -are partially enclosed in concrete compartments and-are thereforeunlikely to be affected by missiles from 'outside the compartmnts.
- If the primary: side of a :steam generator is affected by a missile at least one safety injection line would remain intact arid could therefore mitigate the-effect of the LOCA.
Any missile affecting the secondary side of the -steam gen'erato the ne-a-r would'no impair'the plant's ability 'to..achieve safe shutdown.
This is because the
-location of' the RHR pumps and heat exchangers at the -10' level of the containment provides separation from the secondary side of the steam generators which are located-from approximately elevation 18' to 55.
The pressurizer relief.tank is used.to condense steam from the discharge of:the.pressurizer relief.valves. Loss of this tank by a missile woulld not impact the plant's-ability to, achieve safe shutdown.
The rupture disc-on this tank is-integral with the manhole b6ver and could become a missile.
Because of the manhole's location on the top of the tank, there is -no essential equi ment which could be damaged by this missile.
The three. loop -of the reactor cdolant piping are arranged so
,that one missile or its consequences would not damage all three safety inj&ction points.
This would ail-ow the safety injection system to mitigate the effects of any condition re uiring safety injection.
Based on the abo e, it is concluded that this system's function,. will not be impaired considering internally generated missfies as identified above.
Further, should a. missile create a break in the primary system, the safety injection system-would mitigate the effects of the LOCA.
V.1.b.
Chemical and Volume Control System The Chemical-and-Volume Codtrol System controls and maintains reactor coolant system in entory and purity through the process 'f letdown, purification and makeup. The-system consists 'of'a regenerative-heat. exchanger (and an excess letdown heat exchanger), which reduces the letdown flbw temperature, orifices to reduce~the pressure,.RHR heat exchanger to cool letdown water treatment equipment to remove' impurities,-a volume control tank which provides a reservoir for volune.changes,-chemical mixing equipment charging pumps which returnl the' treated water to the' reactor coolant system, and.a seal water heat exchanger which reduces the temperature of: the reactor coolant -pump seal water.
-6 The charging pumps and seal wate heat exchanger are located in a separate room in the reactor auxiliary building which
.contains no equipment from other systems which might produce missiles. The only sources of missiles in this 'room.. are the charging pumps themselves and the test.pump.
The charging
- pumps are not missile sources because the impellers, if broken,' will not penetrate the thick steel casing (se6 Appendix.1).
-The test pump 'is not used during plant operation.
Non-safety<
related fans are: provided, for backup charging pump cooling.
These fans are not normally used during plant operation.
The regenerative heat exchanger is located inside the.
pontainment at approximately elevation 16 feet.
If this-heat exchanger is damaged by a missile, charging could be accomplished by*.the reactor coolant pump seal water lines.
%All other equipmentin the chemical and volume control system, with 'the exceptionof the refueling water'storage tank, is located -on the reactor auxiliary.building roof.
-The. refueling water storage -tank can,.act as an alternate 'source' for charging upsuction.arnd is located 100 feet fm the equipment.
It is. unlikely.to be damaged byany missilewhich could damage the chemical and volume.control 'system equipmen't because.of the 'distance and intervening equipm'ent. This tank. can therefore be used as an alternate source for charging pump suction to achieve safe. shutdown.
The CVCS equipment on the reactor auxiliary building 'roof is not required to' mitigate the consequehn es.of a LOCA or'to safety shut; down the plant.
Additionally, if'charging flow is'lost, the safety injection system would be available, to 'achieve safe. shut down.
In addition, the residual heat removal system and the auxiliary feedwater" system would be available.
.Based on the above', it is concluded that this system's.
function 'will' not be'impared considering internally generated missiles'as identified above.
.1 c. ' Auxiliar'y.Coolait System The 'auxiliary coolant system includes the component cooling water system and the residual heat removal system.
-7 N.1.c.1. Component Cooling Water System The component cooling'water system transfers.heat from various components to the circulating water system. The component-cooling water system is a closed system with three motor driven pumps, two horizontal heat exchangers anda surge tank. This equipment is located outside on the reactor auxiliary building roof. The spent fuel pit heat exchanger and the recirculation heat exchanger which are also cooled by the component coolihg water system are located in the same area on the roof 6f the reactor auxiliary building.
A component cooling water pump could become a missile source and, damage-the other. component. cooling water pumps,
<(including.th6ir electric motors or cable), or the component cooling water surge tank.
The safety injection and refueling Water. pumps, which are located in this area are not missile. sources '(see-Appehdix 1).
The spent fuel pit pump, which is also in the' area has a case made of stainless steel, which is a ductile material, and is therefore unlikely to, become a nissile source.
The' spent fuel pit heat exchangers, recirculation heat excharger, and component cooling water heat exchangers are not vulnerable to missiles from' the component cooling water pumps :when the assumed trajectory of missiles from these pumps is: considered. ' The auxiliary. cooling pump, because it's.characteristics are similar to the: componert cooling 'water pumps, could 'become"a missile source.
The auxiliary cooling pump is located beside the reactor auxiliary building, approximately'6" below the elevation of the roof. 'Because of the elevation difference, the probability that missiles from the aukiliary cooling pump would "affect these, heat exchangers is low.
Heat.exchangers required for accident mitigation or "safe shutdown which are'cooled by component codling water are the residual heat removal heat exchangers, residual heat removal pump bearing cooling heat exchangers.,I seal water heat exchahger,.reactor coolant pump thermal barrier and bearing cooling heat exchangers, 'and charging pump oil cooling-heat exchangers. The residual. heat rem ovalpumps and heat exchangers are discussed in section (V.1.c.2).
The reactor coolant pump cooling coils. are includ&d in the discussion of.the reactor coolant pumps'(V.1.a.).
The seal. water heat.exchanger, and. charging pump~cooling are included in the discussion of the CVCS (V.1.b..
-8 High pressure nitrogen bottles are stored in the area of the'component: cooling water system equipment. These bottles are restrained by,arack-and partially enclosed by a concrete wall and therefore are unlikely to damage the component cooling water system equipment.,The shutoff valveson the 'nitrogen.bottle's face away from the component cooling water system equipment.
A liquid nitrogen storage vessel is located tb the west of the spent fuel 'pit heat.exchanger,. recirculation heat exchanger, and component cooling water. heat exchangers.
This vessel-could generate missiles that could damage these heat exchangers.
Based on the above, it is con'cluded. that the function of the component cooling water pumps,. component cooling water surge.tanks, and the recirculation'heat exchanger could be impaired by rfiissiles from. component cooling water pumps.
It is concluded that the-r~dmainder of the. system's function will not be impaired considering internally generated.mi si1es as identified, above.
V.1.c.2. Residual Heat Removal (RHR).System The residual heat removal heat exchanger and pumps are provided to remove heat from the reactor coolant system when the reactor coolant system is below 350oF and 350:
psig.
The 'residual heat removal heat'exchanger is also used during normal operation to further 'cool the letdown after it leaves the regenerative or excess letdown. heat.
exchanger.
To achieve.cold shutdown', the RHR pumps take
,suction' from thereactor coolant 'system and pump reactor coolant through' the RHR heat exchangerswhere it is cooled by component-cooling water. The cooled reactorcoolant is the' returned to the reactor cool'ant system".
This system is not :used after.LOCA.
The RHR pumps.and heat exchangers are located.insid' the containment at elevation -10 feet.
The RHR pumps and heat exchangers are required. after a loss of secondary coolant, such as a' Main Steam Line Break (MSLB). -Any missile causing a MSLB is unlikely to damage the RHR pumps and heat exchangers.
The power supply to the RHR pumps'and the main steam lines are loca ted in the same area. 'However, it is unlikely that a missile could damage both items.;
The RHR heat exchangers are located 'below and to the southeast of the pressurizer.nelieftank.
This tank is constructedt'o ASME-Section VIII Standards' and is equipped' with',a power operated pressure'control valveaid a.rupture disc'.
Since the rupture 'disc is integral with'the manway and is located on the top of the tank, the RHR heat
-9 exchangers are not likely to be targets of missiles from this source.
No' other missile sources are in: the area of the RHR heat exchangers.
The RHR pumps are located adjacent to each other.
However, the RHR pump cases: are made:.of stainless steel and are therefore unlikely to b;ecome mis'sile" sources'.
The only other potential missile source which could: impact the RHR pumps is the'reactor cavity dewatering pump. This pump is only used to dewater the react6r. cavity after refueling and i.s also made of stainless steel. It, is unlikely to be a missile source.
Based on, the-above, it is concluided that the RHR 's'ystem's function will. not -be impaired considering internally generated missiles as.. identified above..
V.1.d.
Safety Injection System The SONGS 1 safetyinjection system provides water to the reactor co6lant system in':the event of a loss of primary coolant. Water is pumped from the. refueling water storage tank by the.safety injection pumps to-.the sucti6ri of the -main feedwater pumps which are'used to pump the water 'to the reactor coolant system. 'During the recirculation mode of operation therecirdulation pumps supply water from the containment sump through the. reoirculatiori heat exchanger to the. suction of: the charging pumps' which are used to return the water to the reactor cold leg injection lines.
The equipment evaluated in this sedtion will be limited to the safety injection pumps and the recirculation pumps.
The charging pumps are evaluated in section V..1.b.
The refueling water storage tarik is evaluated in sectionV.1.g. The mai feedwater pumps are evaluated in section V.1.h.
The safety injection pumps are located outside to the west of the turbine -building next to the refueling-water storage tank and auxiliary, transformers 2 an4 3.
The.iearby 4160/480V service transformers 2 -and 3 east of the s'afetyi'Injection pumps could explode but would not generate riissiles (see
'Appendi.2)- The safety injection pumps will not generate missiles (see Appendix 1).
The recirculation pumps are-located next to each-other in the containment sump at approximately'elevation -14 feet.
The only other items that could become missile sources-in this area are 'the sphere sump pumps. The sphere sump pumps are not used during a'LOCA.
They are made of stainless steel. and are therefore, not likely to become missile sources.- The recirculation. pumps are also made of stainless steel and are n6t likely -to becomejriissile sources.
-10 V.1.e.
Main Steam System (Portions)
The. main steam system transports steam -fr6mi the steam generators through the-steam lines to the turbine.
The safety related portion of. the main steam system includes the steam generators, the main steam lines down to the turbine stop valves,,the aux-iliary feedwater;;pump turbine steam supply line, the power operated relief'.valves, and the safety valves. The steam generators are discussed in Section V.1.a.
The steam generators'discharge into a common header at approximately elevatk.39' inside the containment.
The two ends of-the header form two main steam lines which then penetrate the cdntainment and enter the turbine building. The safety valves ahd steam dump valves are located on a header off each main steam line. Both headers are located between the containment and the turbine building.
A supply line for the auxiliary feedwater pump turbine is connectedto one steam line..The two main steam line, then run parallel to-each other under.the turbine deck., The lines then penetrate the turbine deck and are connected.to the turbine stop valves..
The steam lines are of heavy walled design and'construction and'are not likely to-be affected by' missiles. The consequences of.a main steam line break are discussed in Topic XV-2, Spectrum of Steam System Piping Failure Inside and Outside Containifient.
-The atmospheric dump and safety valves can produce missiles.
However, the Sphere Enclosure Building and the Control Building on one side and the Spent Fuel Building on'the other will contain any missiles and direct-them in a.vertical direction;i There is no equipment above these-alves, however, equipiment located outside could be damaged.by falling'valve parts.
However,. the probability is considered -low,that such a missile could. impact a safety related component and it is considered.improbable that redundant safety related components could be impacted.- There are no-other missile--sources in the vicinity, of the valves.',
-Based on the above, it is concluded that this system's function will not be impaired considering internally generated missiles as identified above.
V.1.f.
-CirculatingWater System (Portioris)
The portions -of the circulating water system which are used for safe shutdown or accident mitigation are :the --salt water cooling pumps, the auxiliary salt water cooling pump, and the component cooling water heat exchangers.
The component cooling water heat exchangers are discussed iri Section V.c.1.
~~1 1
The salt water cooling pumps. take suction from the intake structure and pump sea-water through the tube side of the component cooling water heat exchangers, where; heat is removed from the component cooling water.An auxiliary salt water cooling pump is provided for cooling if the salt water cooling pumps fail.
The auxiliary salt water cooling pump takes suction from the plant intake line upstream of the stop gates.
The salt water cooling pumps are located in te open intake
... structure." The auxiliary salt water' cooling pump' is located in a Iseparate pit remote fr om th e salt water cooling pumps.
It is' therefbre incredible that, a.missile could damage' both.
the auxiliary salt! water cooling pump andthe salt water cooling pumps.
Since credit is n6t. taken for the auxiliary salt water cooling pump in determining the operability of the'salt ater cooling system, the effects of internally generated missiles on the.
salt Water cooling pumps were evaluated.
The. salt water cooling.pumps are vertical pumps which take suction frorm the intake structure. Their' cases are' stainless steel and are continuously submerged. The ductile nature of the' case material and the dissipative.effect of the water on impeller fragment energy make it. unlikely that a missile from.
one salt water 'cooling pump could affect the other.
Other items that could affect the salt water cooling pumps are
'the circulating water pumps which are located approximately 27" from the salt.water cooling pumps and 'the" screen wash pumps which are located 7' from the salt water cooling pumps.
These pumps are made of the same materials'and are of' the same type as the salt water cooling pumps.' The same conclusions that were reached for the salt water cooling pumps.apply.'to these pumps." The"-circulating water pumps normilly turn slowly (200-300 rpm) and cannot produce.a very 'enengetic missile.
Oeof. the screen wash pumps is' powered 2by a gasoline engine.
The fuel storage tank i-s located immediately outside and at the edge of the intake -structure-..It is, possibl4 that this' engine -or its'local..fuel storage. tank 'could be 'a" source of missiles. "A failure of thi's engine could disable the salt water coolihg pump (including'its electric motor br cable) im*mediately adjacent to it as well as'the other salt water cooling pump (including its electric' motor or cable)'.
'An explosion of the fuel storage' tank could damage both pumps (including their electric motors or cables).
-1 2 The circulating water system is not a potential source of damaging missiles.. However, the salt water cooling pumps are susceptible to loss of function due to missile-damage.
If the remote.auxiliary salt water -cooling pump can be used, the essential furiction of the system'can be maintained.
Certain
'pipihg located in the salt water cooling pump-area, if damaged, by a missile, could affect cooling from all three salt water cooling puips...
Connections are provided to connect fire water to the component cooling water side-of the heat exchanger in the
-event that all salt water cooling capabilities are lost.
V.1.g.
Miscellaneous Water Systems (Portions)
The miscellaneous water system includes the containnent spray
<system and the plant makeup system.,
V.1.g.1. Containment Spray System The containment spray system is an open heat exchange system.designed -to remove heat from the containment during and after a LOCA or MSLB/FWLB.:
It-consists of the refueling water storage tank, the refueling water pumps, the contaihment spray nozzles, the -recirculation pumps, and-the recirculation heat exchanger. The refueling water
-pumps provide water to; the containmeht spray nozzles. The containment spray water collects in the containment sump.
..The recirculation pumps supply water from the sump through the recirculation heat exchanger to the suction of the refueling water pumps.
The refueling water storage tank act s as the -sourceof water for the safety injection pumps and also. acts as the source for the refueling water pumps and charging umps.
The refueling water storage-tank is also used as an alternate source of water for safe shutdown when certain CVCS equipment is unavailable.
The containment spray systein is used only after a LOCA and MSLB/FWLB. ;The recirculation heat exchanger. is also discussed in Section V.1.d.
The refueling water pump s;located to the, west of the turbilioe. building, could be struck by missiles from the uxi li-ary cooling pump which-is also located to the west of the turbine building. Since there is a six foot
-elevation difference between the roof of the reactor auxiliary building, where the component cooling pumps are located,-and the location of the refueling water pumps, the.refueling. water pumps will not be affected by missiles from the component-cooling-pump.-
-13 The refueling, water pumps will not generate destructive mnissiles (see Appendix 1).
The spent f uel pit'pump also has a stainless steel case which would contain' any" missiles generated by the impeller.
The refueling water sorage tank is located near the refueling water pumps and is subject to missiles from both the component cooling water pumps and the auxiliary cooling pump.
The refueling water storage t ank. is adjacent to auxiliary transformers.2 and 3.' These.
transformers could explode, but will not generate damaging missiles:(see Appendix 2)... The refueling-water storage tank could also be subject to missiles from the primary plant makeup pumps.
These pumps are -made'of stainless steel and are, therefore, unlikely to generate missiles.
The cbntainment spray nozzles are on top of the
,containment and are protected from damaging missiles by the concrete shielding around the reactor, pressurizer, and steam geerators.
V.1. g.2. Plant Makeup System:
The plant makeupsystem consists of the'primary plant makeup tank, the primary plant makeup pumps.and the condensate storage tank. The safety' function of this system is to provide water to the suction of the auxiliary feedwatert pumps. The condensate storage tank is connected to the condenser hotwell and to the' auxiliary feedwater pump suction... When the.condensate storage tank. reaches a low level, the primary plant makeup pumps can be activated to fill the condensate storage tank from the primary plant makeup tank'.
A backup water source to the auxiliary feedwater pumps is provided..by means'of a hose connection through the fire protectioni:system: from. the service water reservoir. At least 3Q minutes is available to realign.,the-suction of the-auxiliary feedwater pumps. The service water reservoir is remote from the condensate storage tank and the primary plant makeup tank and pumps.
It is therefore:
incredible that..it could be damaged by any-missile which could damage the plant makeup system equipment.
Safe.
shutdown can. be achieved in the event of missile damage to the, plant makeup system.
Based on the above, it is concluded that the refueling water storage tank.and refueling water pumps are vulnerable 'to damage from missiles from the component cooling water. pump and the auxiliary coblant pump a.s identified.above. jThe containment spray system is'not a source of missiles.
It is'concluded that the plant makeup system's function will not be imnpaired consider ing internally generated missiles as identified.
above.
-14 V.1.h.
Feedwater and Condensate Systems (Portions)
The feedwater system is arranged such that the main feedwater pumps are.used in conjunction with the safety injection pumps to provide flow to the reactor coolant. system in the event Of a safety injection 'system actuation.
The essential portions of the feedwater systenm are the feedwater pumps and the'inain feedwater lines between the first check valves upstream of the containment and' the steam generators.
The.individual feedwater linesdownstream of the check valves are not likely:to be damaged by internally.
generated missiles because of their location and routing.
During. activation of the safety injection system, the main feedwater pumps are used in series with the safety injection pumps to provide 'bor.ated water from the RWST to the reactor.
coolant system through the' safety injection lines.
- This, requires realignment of valves to terminate feedwater flow and establish safety injection flow..
The main feedwater pumps are located on opposite sides of the turbine building and could.not be affected by the same missile.. Either pump alone-can provide sufficient safety injection flow.
Because the main feedwater-pumps are motor driven with stainless steel cases, it is unlikely that they will become missile sources.
The valves used to realign the' feed pump suction and di-scharge: from feedwater to safety injection are powered by.
hydraUlic actuators. The actuator and its associated accumulator are designed'and fabricated to ASME Section III, Class 2'.
The volume,6f the accumulator' is 1000 in3 with a design. pressure of '4000 psig. The small, volume of gas used in these actuators will' limit the energy of any missiles generated. The valves are located on opposite 'sides' of the.
turbine buildihgadjagent to the feedwater pumps. ' Therefore, potential missiles from the valves in one train could not affect the Other, train The auxiliary 'feedwater; pumps are lodated in the vicihity of the valves on the west side o'f the building; however, 'they are'protected by a massive steel pipe' whip barrier.
Based on the above;: it'is concluded that this system's function will not' be impaired considering internally, generated missiles-as identified above.,".
.Compressed -Air System The compressed air; system consists of the service :air system
'and instrument air 'system.
V.1.i.1. Service Air System The service air-system provides compressed air for the instrument airsystem (see V.1.i.2).
The system consists of three. service air compressors, three aftercoolers,, abd three air receivers.
The compressors and aftercoolets are located in -the turbine
-building.
The air'.red 'ivers are located outside, south of, the turbine building.
While the service air system provides compressed air to.
the instrument air system under normal conditions, during abnormal 'condit ions instrument air can be provided by t he emergency.air compressor and receiver or by local accumulators.
Local nitrogen bottles are also provided for some equipment In addition, there is 'a portable diesel driven'air compressor.available." Because these backups are provided, the service air system does not require'evaluation as apossible missile target.
The service air compressors could generate missiles. The only safety related equipment' that would be affected by these missiles would be the emergency air compressor. The service air receivers (located outside) are ASME Section
'III pressure vessels and are provided with safety valves on top. These relief valves could generate missiles.
There is no' equipment above these safety ralves.
- However, outside equipnfent could 'be damaged by. the falling debris.
The probability is donsidered low that such a missile
'could impact;a safety related component and it is consideied improbable that redundant safety related componen t could'be'impacted.
V.1.i.2. Instrument Air' System The InstrumentAir, System provides clean, dry air to operate various safety related items.,
The' system consists of an.emergency air compressor, a two-vessel dryer,.two air filters, and accumulators at various locations in the plant.
Backup nitrogen bottles are provided for the safety.reated instrumentation
-,required for safe shutdown.or acdident mitigation.
The Insti-ument Air System could produce missiles.
The nitrogen bottles used. for -instrument-air backup could impact an. instrument air header directly overhead.
'-In the Ventilation Building., anotfier nitrogen bottle could impact
-,an overhead instrument air header.
The containment instrument air has only six pneumatic valves, with 'no" instrument air'headers above them.
-16 It is conclUded that the instrument air system's function could.be impaired considering internally generated missiles as identified above.
V.1.j Air Conditioning System (Portions)
The Air Conditioning. System consists of several subsystems which will be described separately.
V.1:j.1. Reactor Auxiliary Buildin Ventilati n System The Reactor Auxiliary Building Ventilating Systeni (RABVS) provides.ventilatiori to the reactor auxiliary building.
Essential equipment required.for safe 'shutdown or accident mitigation located in the reactor auxiliary building are the charging pumps. Failure of the RABVS. is discussed in topic IX-75 Ventilation Systems.
The sys em consists of one air handling unit, which proyides air to the reactor auxiliary building.
The ContainmentSphere.Purging and Exhaust Systein provides exhaust fans to remove the air 'fromnthe.building. The air handling unit is located in the reactor auxiliary building, above the flash, tank pumps.
Equipment which can generate missiles which.could damage the air handling unit are monitor tank pumps, flash tank pumps, the gas stripper'pump,. the decontamination drain tank pump and thie radio-chemistry laboratory drain tank pump. These pumps all have-cases of either ductile iron or stainless steel and are therefore not likely to generate missiles.
The air handling unit could generate missiles
- However, these missiles will-not, effect any equipment whi h would impair-theplant' s ability to achieve safe shutdown or mitigate an accident.
V.1..2. Control Area Heating Ventilating and Air Conditioning Systein The control room Hike is going to be replaced as part of TMI related requirements.
The new design will be protected against the effects of missiles.
The fControl Area Heating Ventilating atd, Air Conditioning.
System (CAHVACS) maintains a. habitable environment in the.
Control Room. -. The system consists of a heat.pump air conditioning unit, an emergency air intake unit, high effi-ciency:and actiVated charcoal filters and exhaust-fans.
-The equipment for this system is located on the second floor of the control and administration building.
Missiles from the heat pump air conditioning unit could damage the Emergency-Air Intake Unit.
Missiles from the emergency air handling units could damge the heat pump air.
conditioning unit.
Additionally, exhaust fan-units could' produce missiles that could disable.. the CAHVACS:.
V.1.j.3. Diesel Generator Building Heatihg and Ventilating System..
The Diesel Generator Building Heating and Ventilating System provides ventilation.to the.Diesel Generator B~ildingduqing normal and abnormal conditions.
The essential portions on this system consist of four -fans for each diesel generator. room.
Since'eachtrai of the.
system is separated from -the other, it is incredible that any missile affecting one train could affect the other (see.Section V.1.k).
V.1.j.I.
16OV Roomn Ventilating System This system provides ventilation for the 416OV Switchgear Room. This system consists of one exhaust fan.
If the fan is damaged by a missile, sufficient,time.is
.,available to arrange alternate cooling before excessive tempeaitures are -reached.
No items required for safe shutdown or accident mitigation,:,
can be.damaged by missiles from the fan.
V.1.j.5.: 4ov Room Ventilating System This-system provides ventilation for: the'480V switchgear room.
This system consists of one exhaust fan.
If the fan is damaged by a missile sufficient tim is available to arrange -alternate cooling before excessive temperatures are reached..
No -items required for safe shutdown or accident mitigation can be damaged-by missiles'from the fan.
It is concluded that-these systems' function. will not be.
impaired.considering internally generated missiles as identified above..
V..k.
Diesel Generators and Auxiliary Systems The diesel generators and their auxiliaries provide-a source of AC. power when the turbine generator is not in operation and, offsite power. is unavailable.-
-8 Two diesel generators are, located in a separate building. The two units-and "their auxiliaries are separated by concrete
'walls. 'Each diesel generator has:'its own separate buried fuel dil 'storage tank... The pumps which supply fuel to the diesel generators 'are approximately 70,' apart and are not likely to be disabled by--the same missile.
It is,concluded that this system's function will not be-,
impaired considering internally generated 'missiles as identified 'above'.
V.1.1.
Auxiliary Feedwater System The safety function of the auxiliary feedwater system is to provide. an assured source of feedwater to the steam generators when-the main feedwaterpumps.are not available. The system consists~ ofone turbine driven pump and one electric motor driven pump'. "These pumps take suction from. theicondens'ate storage tank and inject water into the main' feedWater lines
'immediately u pstream of'the containment"penetrations. The condensate' storage tank 'is discussed. in. SectionV.g.2.
Both auxiliary fe'edwater pumps arelocated in the turbine building at elevation14'.
The pumps are partially enclosed by a 1/8". thick steel enclosure..originally designed for pipe whip and j't impingement protection. The most likely 'source of missiles affecting the auxiliary feedwater system is'the pumps themselves.
Both pumps have cast steel casings.
Because of the thickness of these casings and their ductility iti's unlikely-that they could produce missiles. -The steam turbine" also has a cat steel case which would tend to 'contai any missiles-generated by a turbine rotor. failure.
The turbine is equipped with, normal and emergency"governors to prevent overspeed._- The steel enclosure would tend to prevent' the effects of missiles on' the pumps and contain any missiles generated :by them.*
Other-sources of missiles' that could affect the auxiliary feedwater pump's or their auxiliaries 'are the. west feedwater/safety injection realighment valves actuators and the emergency air compressor.
-A safety valve is provided 'on the steam supply line to the turbine.: "This valve is only' under pressure when the steam driven auxidliary, feedwater'pump is in operation. This.. safety valve is located on the west wall of the turbine building and
- _.-.could become a missile.- While. no equipment is located above this safety valve, damages could.occur to safety related equipment when 'debris falls back to the ground.
HoweVer, the probability is--considered low that such-a'missile could impact.
a Safety. elated comorent 'and.it is considered improbable
-that redundant -safety related -component s could be impacted.
-1 9 Based on the above, it is concluded that this. system's function will rot, be impaired considering internally generated missiles as identified above.
V.2.
Systems'whose failure may result in release of unacceptable amounts of radioactivity:
V.2.a.- Reactor Cycle Sampling System The reactor. cycle sampling' system provides samples for
'laboratory analyses which serve to guide the operation of the reactpr coolant.system and the. cliemical and 'volume control system The system.:consists.of',a, delay coil, sample heat exchangers, and sample pressure vessels. 'Samples are obtained by conducting the sample through a heat exchahger into,.a sample pressure vesselv.
A delay coil is provided for reactor coolant samples.
.The system is operated intermittently.
If a missile strikes t'he system:while it is not in operation, no significant release of radioactivity will result.
If.
a missile strikes the system while it is in'operation, the 6ontainment isolation valves provided will be closed and no signifi.cant release of radioactivity will resuit.
The sample pressure vessels are designed for 2585 psig and.
6500F, and have.
maximum volume of' 75 ml. Because of thei small size, it i.s:highly unlikely that they could become damaging missiles.
It is concluded that 'this system' s ability to contain radioactivity will not be impaired considering internally generated missiles as identified above.
V.2.b.'.Radioactive Waste Disposal Systems The radioa'ctive waste disposal system consists of four
'subsystems -which will be described separately.
V 2.b.1. Radioactive Liquid Waste System The-'radioactive liquid waste system holds. liquid wastes for radioactive deday of short half-life radioactive contaminants, processes liquid-wastes to remove. long half-life radioactive contaminants, arid discharge liquid wastes to the envirohmedt under controlled conditions.
The system :consists of a flash tank, flash t ank pumps, a radiochemistry laboratory drain tank, a radiochemistry labratory' drain tank pump, a decontamination drain tank, a decontaminati6n draih tank pump, liquid radwaste holdup
tanks, holdup tank..pumps, a circulating pump, radwaste ion exchangers,.a gas'stripper, a gas 'stripper pump, monitor tanks, and monito'r-tank'pumps.
-20.
All the radioactive liquid wastes system equipment is located in the lower level of the reactor auxiliary build i
-g If damaged by a missile,: the liquid would, be contained within the. reactor auxiliary building and would not. result in a significant release of radioactivity. 'Any gases or suspended'.particles would be controlled by. the Containmient Sphere Purging aind Exhaust System.
It is concluded that this system's ability to-control radio'activity' will not be impaired considering internally' geherated'..missiles as identified above.
V.2.b.2. Radioactive Gaseous Waste System The radioactive gaseous waste system holds'gaseous.wastes for radioactive decay of short half-life radioactive-.
contaminants and -discharges:gasebus wastes 'to the environment under controlled conditions. This system consi.sts. of a waste gas surge tahk, waste gas compressors, and waste gas decay tanks..
The equipment for this system is located in the lower level of-the reactor auxiliary building.
The waste gas.
system is operated at pressures less-'than 120.psig. 'The' total pressurized gas volume is.apprdximately 500 ft3.
Missile damage to this system could result in' release of radioactivity.
The waste gas surge tank a'nd the. waste gas decay t;aks -are located in a common shielded room.
The shielding: will prevent any missiles from entering the room. The tanks are all designed to the ASME Code and are equipped with relief valves.
The relief valves are.located butside the room. It.is our judgement that these tanks ar'e unlikely to generate iissiles.
Missile damage to the waste gas compre ssor' will not result in a significant release of radioactivity.
It is condluded that tfhis system's ability to control radioactivity will, no' be impaird considerin internaly generated'missiles as identified above.
V.2,;.3. Radioactive, SolidW aste System The Radioadtive Solid Waste System, holds wastes for radioactive,idecay of-short half-life radioactive contaminants. This system consists of' a baler 'and shipping drums.
The baler compresses soft, material into. a compact form for placement in drums.
Noncompressible solids,are.also to-be placed. in drums. This equipment is. located on the roof of the react6r auxiliary, building., Missile -damage to this system will not result in a sign ficant release of' radioactivity.'
-21 It is concluded that this system' s ab.ility to control radioactivity will not be impaired considering internally generated missile's-as identified above.
V.2.b'.4.' Resin Supply and Removal System The resin s ppiy and removal system nemoves depleted radioactive -resin.sfrom" various plant demineralizers, store's such."resins prior 'to removal, and provides new resins to ion "exchangers.
The, system consists of a new' resin slurry tank and a, spent resin storage tank.
This equipment' is located on the lower level of the reactor auxiliary building.
If.damnaged'.by a missile,' the contents of the.system would be contained within the reactor auxiliary'-building-and would, not -result in' a significant release of'radioactivity:.':
It, is cocluded that this system' s-ability to control radioactivity will not be impaired considering: internally generated missile s-as identified above.
V.2.c.
Air 'Conditioni'ng.System (Portions)
V.2.c.1.
Contaiinment Sphere Cooling and Filtering System,.Control Rod Dri reMechanism, Cooling System,"' Reactor.Cavity Cooling System,.Reactor Auxiliary Building Ventilating System (RABVS), 'Coi'trol. Area Heating Ventilating and Air Conditioning System, Administration'Building Heating, Ventilating abd Air.Condi'tioning System, Diesel'!Generator Building Heating and Ventil'ating'.System, 4160V Room Ventilating.System; and 480 Rooin Veritilating System Failure of these systems will not result in significant release of radioactivity.
V.2.c.2. Fuel Storage Building Ventilation System The function, of the Fuel Storage Building' Ventilation System (FSBVS)"is to maintain ventilation in.the spent fuel i.ool equipment areas, to permit personnel access, and to control airborne radioactivityih the area during.
normal.operation, anticipated operational transients, and followingpostulated" fudel handling 'accidents.
Based on. our 'review of the FSBVS fuel handling accide'nt analysis in'the SONGS I.
FSA, 'we find that the. system is not required.th prevent' an unacceptable release of radioactivity'.
-22
'V.2.c.3. Containment Sphere Purging and Exhaust System The function ofthe Containment Sphere Purging and Exhaust System (.CSPES) is to exhaust air from 'the RABVS and the FSBVS after filti'ation or other treatmet. and' also. to supply 6utside air:to the containment sphere. wheh personnel access is required. During normal operation, the.CSPES is used to exhaust air, from the. RABVS aiid the FSBVS,.
Purging and exhaust from the containment is used only during shutdown and is isolated during normal
-operation by isolation valves.
The-CSPES consists of three air handling units, A-21, A-22 and A-24 and associated ducting.
Suction dampers (PO-19 and PO-20) and discharge damper s (PO-17 and PO-18) are also provided on air handling units A-22 and A-24, respectively..
HEPA filters are provided on'Units.A-22 -and A A prefilter is provided on Unit A-21..
Failure of both air handling units. A-22'and A-24 simultaneously would result' in loss of. ventilation to the reactor auxiliary building or containment 'sphere.
The equipment used in' the CSPES is-located, in an equipment room located adjacent to 'the spent fuel' building.
The onlyequipment located in this room that;could be the source of missiles is.the ventilation equipment itself.
Air handling units'A-22 and :A-24 are arranged so that missiles from either of these items will'. not "impact other equipment..However. a missile from,air. handling unit A-21 could-disable both air: handling units A-22 and A-24' itaneously.
However, this air handling unit has a case which would probably contain,,any missiles.
In any.
case, there should be ample time to effect repairs to this system.
Two hydrogenr Iecombiners are provided to remove hyrogen from the containment after a LOCA. They are located on opposite sid s of the containment so that.a missile damaging one'will not' damage' the other.
It is cohcluded that thissystem sability to contain radioactivity will not be impaired consideringinternally generated missiles as identified above.
V.2.d.'
Auxiliary Coolant Systei (PQ ntiohs)
The auxiliary coolant syst em provides cooling to the spent fuel pool which is used to prevent boiling ahd a. subsequent release-of unacceptable amounts of radioactivity. The.system
'is'a closed loop system consisting of one spent fuel'pit pump and'onespent fuel pit heat exchangeri>.
The pump takes.suction from the spent fuel pit "and provides. borated water to the spent fuel it heat exchanger.
The cooled borated water.-is then returned to spent fuel pool.
-23 The spent fuel pit heat exchanger is located on the roof of the reactor auxiliary building. The. spent fuel pit !pump is located next to the refueling water storage tank to the-west of the turbine building.
Should aby of this equipment become inoperable due to missile damage, there is sufficient time to-make r.epairs or arrange alternate -cooling. :The spent fuel pit-pump, is made with a stainless steel-case and is therefore unlikely to be-a source of missiles.
It is concluded that this system's ability to contain radioactivity will not be impaired considering internally
-generated missiles as identified above.
V.3 -'Electrical Systems Needed to Support Systems Required to Perform Safety Fun.ctions
.3.a 4160V System The 4160V System includes the'4160V Switchgears No. 1A, 1B, 1C, and 2C, and Emergency Diesel Generators Nos. 1 and 2.'
Switchgears No.
1A and 1B provide power to Reactor Coolant Pumps A, B, and-C, and the generator exciter.
This equipment is not-heeded for a safe shutdown of the plarit.
Switchgears No. 1C and 2C are redundan-t and provide,power to equipment required for-a safe shutdown of. the plant. They are located.-in:, theI kV switchgear room in two cubicles facing each other five feet apart.
As indicated in Appendix-2, the compartment doors of the 4 kV switchgears could become missiles'.
A compartment door originating froin -one. 4 kV switchgear could hit the other switchgear. However, the energy remaining at the impact would be limited because of the energy reqiired to break the hinges and-to displace a heavy door.-:
This could impact the safe shutdown of the plant because both redundant-switchgears would be damaged. -H6 wever, as indicated.
in-Appendix -2, such an event has a very low probability.
-'480V Motor Control Center No.1, located behind 4 kV switchgear 2C,- could also be a source.of ~missiles hitting 4 kV switchgeai' No9.2C;, however;, the backup)4>kV.switchgear No.
iC would still be-available for a safe shutdown of the plant.
24 With the exception of a small ventilating fan, the kV
- 'switchgear room does not -contain any mechanical equipment which could be a potential source of missiles.
The small; ventilating fan near the :east door could.possibl.generate.
missiles, but the filter and fan shroud would-probably absorb the fragments of the rotor.
If a missile occurred, it could hit the nearby relay bar'd 'and damage some 'elays; however, no safety 'furiction would, be affected because these relays are generator protection relays 'and do, not support safety related equipment.,,
Emergency Diesel Generators No. 1 and 2 are redundant and physically separated;the refore, any missiles generated in these areas would not..affect the safe shutdown of the plant (see V'.1.k).
Based on the. above, it is concluded that this. system's.
functioqn ~could be impaired considering internall generated missiles from the 4 kV switchgear as identified above.
X1.3.b
'480V System The 480V System consists ofA80V switchgears.1, 2, and 3 served respectively. by 4160/480V service-transformers 1, 2 and 3,.'and motor control. centers 1 through 3.
480V switchgears 1 and"2,are.redundant and provide power to equipmeht required for a safe shutdown of>.the plant (safety related load).
480V switchgear 3 serves only one safety related load; the Component Cooling Pump C.
Switchgear No. 1' i-s located in the 4 kV switchgear room separate from its backup switchgear No.
2' located in the 480V switchgear,'room with switchgear No. 3 and the lighting:
distribution switchboard.
_480V Motor Control Center o
2,'located in front of 480V swi-tchgears Nos.'2 and 3-pouild be a. source of missiles hitting 480V switchgears.2 and 3; however, the backup 480V switchgear No." 1 would still be available for a. safe shutdown
-of the plant.
As -indicated by Appendix-2-j 4160/480 V'service transformers 1 2, and 3 cannot-be a source of missiles. Reduidant*
transformers 1 and 2 are physically separated (No. 1 near the health physics building, Nos. 2 and 3 west'of the 480V switchgears No.2'and 3.room).
Therefore, separation of the redundant 480V equipment will always ensure a' safe shutdown of the plant.
-25 Based on the above, it is concluded-'that this system' s function will not be impaired considering internally generated missiles as identified above.
V.3.0 1 5V DC System The 1.25V DC System consists of two redundant sets, No.
1 and No. 2; each containing a bus, a battery, and two battery chargers.
No. 1 set is located: in the south side of the administration an'd control building separate from. No.: 2 which is. lobated.in the Emergency Diesel building.
In each location, the battery is located in a room separate from the room where the switchgear and the two battery chargers are located-Therefore,.explosion of one. battery as indicated in Appendix 2.would generate missiles affecting only. this battery.
For each of the'three motor operated safety injection valves 850 A, 850 B, and 850.C located inside containment an
'independent power source is provided. Valves 850 A. and 850 B "areserved through,Motor Control Centers 1 and.2 respectively, which are powered from.48(V switchgear 1 and.2.
Valve 850 C is served through Moto_ Control Center 3 wh*ich is powered from 480V swi-tchgear No. 3, with-an uniterruptible'power supply system.
This uninterrupted power supply includes -a separate 125V DC battery used as a backup.
This battery islocated south of the 'condense'r near the hydrogen seal unit.
Explosion and generation'of missiles from this battery would not affect the normal operation of' the valve, 'assuming only single failure.
The battery is isolated by a fence from the battery charger and the inverter.
In addition, the other two valves' 'and their power suppliefs could not be affected.
Because of this. separation of the redundant equipment, the safe shutdown of the plant would not be affectedby intbernally generated missiles Based. on the above, it is concluded that this system's function will not be impaired considering internally generated missiles as identified above.'.
V.3.e 120 AC System The 120V AC'Systemyequired for the safety functions of the plant includes.120V.ac Vital Buses 1 through 6, located in the cntrol rooi.
Inverters 1, 2, and 3 serving 120V AC Vital Buses 1 through 3A are'located in the DC.swit'hgearroomof 125V. DC; Bus No.
- 1. Inverter 5 serving 120 V AC vital buses 5 and 6 is located -in the 480V switchgear room near the lighting switchboard. An additional inverter, served from 125V-DC bus No. '2, providing 120V.AC power for the containment spray.
activation system, is located in the control room..
-26 None of this equipment has the potential of generatihg missiles or -being damaged by missiles generated by other equipment.
It is concluded that this system's functiof'will not be impaired considering internally generated infissiles as identified above.
V'A The control room is designed to provide a central location friom which the status of the plant can be determined, and modified as required.
The-control room is located at eleVation 42" 0" immediately east of the turbine deck., It is-enclosed with walls on the north, east, and west that would-deflect or, stop any internally generated missile originating outside the control room. The s6uth'wall and roof p'rovide less resistance to missiles. 'However, no missiles can reach the.control rooi from the south wall'.
The roof can be impacted.by missiles generated by main steam, safety valves, the steam:dump,valyes, the auxiliary feedwater pump steam supply safety valve, and the air receiver safety valves.
- However, it is, considered improbable that such 'a missile would impact safety related.equipment in. the cont'rol room." In..addition, safe shutdown can be achleve'd from the remote shutdown panel.(C-38-).
LOCA mitigation requires access-to the control room.
The only items capable of generating missiles inside the control room are oxygen bottles and fire extinguishers. The oxygen bottles are rated at-t2500 psig and are of the type used 'in hospitals.
They are not considei d'to be missile' sources. The fire extinguishers are of two types; aCO bottle pressurized at 1800 psig and a.
Halon bottle pressurized at' 175 psig.
If these items were to generate missiles from the valves at the :top "of.the bottles, the ceiling would be the only location affected.
There is no safety related equipment located on the. ceiling.
It is 'concluded that the control room's function will rot be impaired considering' internally generated missiles,, 'as identified above.
V I.-
CONCLUSIONS From our review of the systems and components needed to perform-safety functions,., we' conclude that the design of protection from'internally generated missiles meet the intent of the criteria listed in Section. II Review Criteria and" are, therefore,: considered to. be acceptable except
'for' those items listed' below:,'
A.
Component.,Coolitg Wat '& Pumps
'B. Component'.Cooling aWter Surge Tan k C. Recirculation Heat Exchanger D. Salt Water Cooling PPmps E. Refueling Water Pumps
-27 F. Refueling WaterStorage Tank G. Instrument Air Header H. Auxiliary Feediwater Pumps kV Switchgear VII. REFERENCES
- 1.
SONGS 1 Final Safety Analysis KEvans:1222 2
1-1 APPENDIX 1 PUMP MISSILE ANALYSIS I.
MISSILE SOURCES We have performed an analysis of the Safety Injection Pumps, Refueling Water Pudips., Charging Pumps, and 'Comporient-Cooling Water Pumps to determine whether these pumps can become missile sources.
These 'pumps are lopated, in the same area on or near the roof-of the reactor auxiliary.building.
jIn-the analysis, pump impellers were assumed to fail in the manner that
-would generate a, fragment of maximum energy.
The fragment energy and trajectory was determined.
The :m6mentum and.energy tran.fer between the fragment and the' pump 'casing was evaluated.,
The energies available in the pump'casing to prevent failire on fragment impact were determined.
The various faillure modes of the pump casings were evaluated' to determine if a' missile'can be ejected from 'the pump.
The.analysi-s makes several conservative assumptions, such as infinite -impeller hardness, unreinforced pump casings and 'a maximum energy :impeller fragment.
The. 'analysis. shows that no impellee fragment could-penetrate the casing of" any o'f. the pumps analyzed, except for the component cooling water pumps.
"The component cool'ing.water pumps fail to contain missiles for' two reasons:
- 1.
The pump casing is made with cast -ion which is a very poor, absorber of energy because of its lack of -ductility.
2.'
The pump casing walls are thin (3/8").
The auxiliary coolant pup-has characteristics (speed', material and capicity) simila to the' component cooling water pumps.
Therefore, the three component cooling water pumps and the auxiliary coolant pump can be-considered as potential missile sources.
All other pumps in the -plant with ductile casings (stainless steel.or cast steel) will not be'a'ssumed t6 be missile sources.' This is based on the large
-margin of safety available, for thepumps analyzed.
These pumps all have stainless steel-cases.
1I.
MISSILE TRAJECTORIES When '-turbi'es', piUmps or other rotating equipment fail,'the most likely trajecory. of the resulting missile is normal,.to the shaft axis. The.
data -available< for turbine missiles indicate that missiles have been ejected at angles 4at from 0o to,220 from normal to the shaft axis.
(References 1.A-and 1.B) The missiles not ejected at- 00 from normal were deflected by stationary p'arts' of. the turbine.
-oe wih o
r, e s-2.
c In order to define the space over whichpump missile ources-will act it will:be -assumed that impeller fragments are ejected at.angles from
-30 0 -to +300 from normal to the shaft axis. The -range of the missiles will.be limited by the first large item of equipment encbuntered. Missileswil1l also be-assumed to be blocked by walls.
This missile trajectory -space would enclose all the missiles that have
-been ejected :from; the turbines of references 1.A and 1.B.
Once a missile is ejected from a pump it is likely that other missiles will also be ejected from the same pump-due to the-unbalance and subsequent
'disintegration of the impeller.- Therefore, it will be assumbd that all equipmentwi hin the missile trajectory space could be affected.
III.
REFERENCES--
1.A S. H. Bush, "Probability of-Damage to Nuclear -Components Due to Turbitie Failure,"fol. 1 4, No. 3, NuclearSafety, May-June 1973, pp.
187-201 1.B S. N. Semanderes, "Methods of Determining the Probability of a Turbine Missile Hitting a Particular Plant Region", USAEC Report WCAP-7861 Westinghouse Electric Corp., February 1972 KEvans:1222
2-1 APPENDIX 2 ELECTRICAL EQUIPMENT MISSILES ANALYSIS I.
ELECTRICAL EQUIPMENT AS POTENTIAL SOURCE OF MISSILES The potent-ialfr generation of missiles' was evaluated for the electrical equipment at the.San Onofre nuclear plant Unit. Nd. 1.
A.
Transformers Explosions:of transfdrmers with ensuing oil fires are caused by tfailure of winding insulation with arcing resulting in sudden generatibn of gas bubbles.
If. this-generation of gas is too-fast to be interrupted-by sudden pressure, relays, or if these relays fail to operate properly, or if spring loaded safety valves'operate too
'late, 'exessive pressure can break and project, the bushings and bur st open the walls and seam~s-of the-oil. tank. 'This is accompanied by projection of ignited.oil. -'Therefore, only the bushings can become missiles..
The.-main 230/18 kV transformers, and the'230/4.16 kV auxiliary transformers A, B, and C, have bushings which can become missiles.
However-,-the 4160/480V service. transformers 1, 2, and 3 have buhifg 'which' are within the enclosure of the ducts of the incomingi celils.
Incase of transformer failure, this enclosure would prevent the bushings from becoming missiles.
B.
Electric Motors Generation of missiles by electric motors is such an unlikely event that it can be reasonably neglected.
If a rotor fails, protection is.provided by the stator, and the stator enclosure-which surround it, and by, the motor casing.: The' fan blades on the end's of-the rotor.core can break and become missiles-; but, -because, of. their lightweight constiruction and small inertia, they are..likely to remain within the m'otor casihg.
C.
41160V 'and '480V Switchgears and Motor Control Centers 4160V 'and 480V switchgears and motor dontrol centers can generate missiles as a result of -failure of the inconing cables or the circuit breaker, which could be caused 'by failure of a relay to operate properly. Combustion' of cable -material due to excessive current generates gas, which can create excessive pressure and sresult in bursting open a compartment-door if the door is not bolted
-shut. Depending on the pressure-generated, the door. can swing on
,, its h'inges, or break its hinges 'and become, a missile.
This type of event -has occurred 'at several nonnuclear locations during the operating history of-Southern-California Edison Company.
2-2 In the worst case, the hinges broke but the door was displaced by only one or two: feet. Therefore, even though this type of event is
- possible, it' is still a very. unlikely' event..
D.
125V DC Batteries 125V DG-batteries can become a source of missiles.. Batteries can explode if a spark is produced in their vicinity, where hydrogen accumulates and' can form an.explosive mixture with air. Sparks 'can be caused by accidental. contact of battery terminals with metallic objects resulting in short circuits. The explosion Can project battery caps or fragments of the battery walls.
II.
ELECTRICAL.EQUIPMENT AS POTENTIAL MISSILE IMPACT, All electrical equipment can be damaged by missiles generated by failure of other equipment (electrical or mechanical).. In particular, electric motors and cables or cable trays could be damaged by' missiles generated by failure of impellers of nearby pumps.
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