ML042960549

PVNGS Updated FSAR, Ldcr 02-F023, Revision 12

ML042960549
Person / Time
Site:	Palo Verde
Issue date:	06/30/2003
From:	Arizona Public Service Co
To:	Office of Nuclear Reactor Regulation
References
FOIA/PA-2004-0307
Download: ML042960549 (13)

Text

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PVNGS UPDATED FSAR 8.2 OFFSITE POWER SYSTEM 8.

2.1 DESCRIPTION

The offsite power system consists of six physically independent circuits from the Arizona-New Mexico-California-Southern Nevada power grid to the PVNGS switchyard. Offsite power from the switchyard through three startup transformers and six intermediate buses is provided to supply two physically independent preferred power circuits to the ac power distribution system of each unit.

The offsite power system is described in this section and is depicted in figures 8.1-1 and 8.2-1.

8.2.1.1 Transmission Network The transmission system associated with PVNGS supplies offsite ac power at 525 kV for startup, normal operation, and safe shutdown of Units 1, 2, and 3. The six 525 kV lines of this system, PVNGS to RUDD, PVNGS to Westwing I, PVNGS to Westwing II, PVNGS to Kyrene, PVNGS to North Gila, and PVNGS to Devers, cover distances of approximately 37, 44, 44, 74, 114, and 235 miles, respectively.

All six transmission lines associated with PVNGS traverse relatively flat terrain and their design meets grade B requirements specified by the National Electrical Safety Code, sixth edition.

The Code specifies loading areas, wind loads for towers and conductors, and safety factors to be used. The conductors and the overhead ground wires are dampened to maintain acceptable levels of vibration. None of the 525 kV lines associated with PVNGS cross one another. There is a crossing of the Westwing I and Westwing II lines by 525 kV line not associated with PVNGS, approximately 43 miles from PVNGS.

June 2003 8.2-1 Revision 12 LDCR 02-F023

PVNGS UPDATED FSAR OFFSITE POWER SYSTEM The six transmission lines associated with the PVNGS switch-yard, and their rights-of-way, are designed so as to minimize line proximities that could result in simultaneous failure of

• more than one circuit. Based oh-historical transmission system data, the frequency of occurrence for breakage of the span of line that crosses the two Westwing and Westwing lines is 1.1 x 105 per year. In the highly unlikely event of grid instability resulting from simultaneous short-circuiting of both Westwing lines, a loss of all nonemergency AC power event could result. This design basis event is evaluated in chapter 15.

8.2.1.2 Switchyard and Connections to the Onsite Power System Prior to the construction of PVNGS there were no transmission lines to, or transmission switchyards in the vicinity of, the site.

Construction of PVNGS includes construction of a 525 kV switchyard of the breaker-and-a-half design in which three breakers are provided for every two terminations, either line or transformers. The switchyard is connected to the six 525 kV transmission lines associated with PVNGS, the 525/24 kV tuibine-generator main transformers, and the 525/13.8 kV startup transformers, as shown in figure 8.2-2. These figures reflect the development of the switchyard as each unit is added.

Each turbine-generator connects to the switchyard through a main transformer, a 525 kV tie line, and two 525 kV switchyard breakers, as shown in figure 8.2-2. Physical connections between the units and the 525 kV switchyard are shown in figure 8.2-1.

June 2003 8.2-2 Revision 12 LDCR 02-F023

PVNGS UPDATED FSAR OFFSITE POWER SYSTEM The three startup transformers connect to the switchyard through two 525 kV switchyard breakers each, and feed six 13.8 kV intermediate buses. These buses are arranged in three pairs, each pair feeding only ode unit.

The intermediate buses for Units 1, 2, and 3 are inter-connected to the startup transformers so that each unit's buses can access all three startup transformers when all startup transformers are connected to the switchyard.

The intermediate buses are connected to the onsite power system by one 13.8 kV transmission line per bus (two per unit). These lines are physically separated to minimize the possibility of simultaneous failure of the lines.

8.2.1.2.1 Switchyard and Offsite Power System Development Figure 8.2-2 depicts the switchyard and 13.8 kV bus arrangements.

Necessary 525 kV breaker installation is accomplished during refueling, if possible, or during operation. All operating 525 kV positions are transferred to the opposite bus: thus, continuity of offsite power is maintained.

8.2.1.2.2 Water Reclamation Facility Load Shedding The Water Reclamation Facility loads are load shed from the Unit 1 intermediate buses upon a Unit 1 BOP ESFAS Mode 1 signal concurrent with switchyard voltage at or below a value which could result in a trip of offsite power in the event of a safe shutdown or emergency event.

June 2003 8.2-3 Revision 12

PVNGS UPDATED FSAR OFFSITE POWER SYSTEM 8.2.1.3 Compliance with Design Criteria and Standards The following analysis demonstrates compliance with General Design Criteria 17 and 18 of 10CFR50, Appendix A, and Regulatory Guide 1.32.

8.2.1.3.1 Criterion 17 -- Electric Power Systems In addition to the features detailed in paragraphs 8.2.1.1 and 8.2.1.2, compliance with Criterion 17 is further demonstrated by the following:

A. If one of the two 13.8 kV startup transmission lines per unit is interrupted, the remaining line can supply offsite power to both engineered safety features (ESF) buses, as shown in engineering drawing 01, 02, 03-E-MAA-002.

B. The two 13.8 kV transmission lines, supported on independent structures, are separated so as to avoid the possibility that the structural collapse of one will cause an outage of the other 13.8 kV line.

C. The. 13.8 kV system is protected from lightning and switching surges by lightning protective equipment and by overhead static lines.

D. Design of the 125 V-dc system-for the switchyards con-sists of two independent dc.systems. Each of the two systems consist of a separate 125 V-dc battery, battery charger, and distribution system. Cable separation is maintained between the two systems. A-single failure caused by a malfunction of either of the two 125 V-dc systems does not affect the performance of the other system. The ability of the switchyards to supply off-site power to the plant is not affected by the loss of one of the two 125 V-dc systems.

June 2003 8 :2-4 Revision 12

PVNGS UPDATED FSAR OFFSITE POWER SYSTEM E. Two isolated 13.8 kV supplies from the intermediate 13.8 kV buses are provided to the switchyards. The ac load is divided between two power panels and loss of one feeder from the.plant does not jeopardize con-tinued operation of the switchyard equipment.

F. For reliability and operating flexibility, the switch-.

yard design includes a breaker-and-a-half arrangement for each circuit along with breaker failure backup protection. Each breaker has two trip coils on separate, -isolated dc control circuits. These pro-visions permit the following:

1. Any transmission line can be cleared under normal or fault conditions without affecting any other transmission line.

2. Any circuit breaker can be isolated for maintenance without interrupting the power or protection to any circuit (subject to'limitations of power system development paragraph 8.2.1.2.1).

3. Short circuits on a section of bus can be isolated without interrupting service to any circuit other than that connected to the faulty bus section.

G. The offsite sources from the 525 kV switchyards to the startup transformers are separate and independent. The failure or structural collapse of one system or structure does not affect other offsite sources.

H. The offsite sources from the startup transformers to the 13.8 kV switchgear located at the units are independently and separately routed.

I. Two physically independent circuits are provided for offsite power to the onsite distribution system for June 2003 .8.2-5 Revision 12

PVNGS UPDATED FSAR OFFSITE POWER SYSTEM each unit. The offsite source normally connected to each ESF bus is immediately available to supply components important to safety following a postulated loss-of-coolant acciderit. Either of the two offsite sources to each ESF bus, if available, can be connected by control switch operation in the control room.

(subject to the limitations of power system development paragraph 8.2.1.2.1).

8.2.1.3.2 Criterion 18 -- Inspection and Testing of Electric Power Systems The 13.8 kV and 4.16 kV circuit breakers can be inspected, maintained, and tested on a routine basis. This can be accomplished without removing the generators, transformers, or transmission lines from service (subject to limitations of power system development paragraph 8.2.1.2.1).

Transmission line protective relays can be tested on a routine basis. This can be accomplished without removing the transmission lines from service. Generator, main transformer, and service transformer relays are tested on a routine basis when the generator is offline.

Onsite power components will be periodically inspected and maintained as required. This can be accomplished without removing the transmission lines, generators, or transformers from service.

8.2.1.3.3 Regulatory Guide 1.32 As described in paragraph 8.2.1.3.1, listing I, an independent immediate access circuit is provided to each Class lE bus for each unit.

June 2003 8. 2-6 Revision 12

PVNGS UPDATED FSAR OFFSITE POWER SYSTEM 8.2.1.3.4 Industry Standards The design complies with applicable standards and recommendations of:

• Institute of Electrical and Electronics Engineers, Inc.

(IEEE) National Electrical Manufacturer's Association (NtMA)

• National Electrical Code (NEC)

• American Society of Civil Engineers (ASCE)

• Underwriters' Laboratory, Inc. (UL)

• American Iron and Steel Institute (AISI) 8.2.2 ANALYSIS TIfe transmission system associated with PVNGS is planned so that the loss-of a single transmission element (i.e., line or transformer) does not result in loss of load, transmission overload, undervoltage condition, or loss of system stability to the Arizona-New Mexico-California-Southern Nevada extra high voltage (EHV) grid. Offsite power supply reliability is determined by the performance of the six 525 kV supply circuits associated with PVNGS. The source stations for these circuits (RUDD Westwing, Kyrene, Miguel, and Devers) all have three or more connected circuits of 230 kV and above, which provide the appropriate reliability.

Power flow studies conducted for the described system indicate that the system can reliably deliver power to all project par-ticipants using the above planning criteria. Dynamic stability studies.have shown that the system can withstand the following disturbances without loss of system stability or loss of load:

June 2003 8.2-7 Revision 12 LDCR 02-F023

PVNGS UPDATED FSAR OFFSITE POWER SYSTEM A. A permanent 3-phase fault on the switchyard 525 kV bus with subsequent loss of the critical 525 kV line.

B. A sudden loss of one of the three PVNGS units with no underfrequency load shedding measures in effect.

C. The sudden loss of the largest single load on the Arizona-New Mexico-California-Southern Nevada system.

In-withstanding these-disturbances, which are used as design criteria, the system exhibits a very stable response, with significant positive damping achieved and with system frequency deviation held within acceptable limits. (Salt River Project letter to APS # SALT RIVER PROJECT 20020206, "Final Report for the 2002 Palo Verde / Hassayampa Operating Study",

2/6/2002). These results represent the response of the system associated with PVNGS with 7t generation stability margin.

Although these studies conclude that a PVNGS unit trip would not cause grid instability, certain chapter 15 accident analyses conservatively assume that offsite power is lost as a consequence of a PVNGS turbine trip. Refer to section 8.3.4 and table 15.0-0.

Grid availability data on EHV systems in the area indicate an outage rate of 2.08 total outages per year per 100 line miles.

Of these, 1.08 are due to.planned outages and 1.00 are due to forced outages. Due to all causes, the outage ratio for 500 kV lines in the area is 0.00180.

On 230 kV systems in the area, similar data indicate outage rates of 6.59 total outages per year per 100 line miles. Of these, 2.97 are due to planned outages and 3.61 are due to forced outages. Due to all causes, the outage ratio for 230 kV lines in the area is 0.0394.

June 2003 8.2-8 Revision 12

PVNGS UPDATED FSAR OFFSITE POWER SYSTEM These outages are most commonly attributable to lightning.

Other causes are fog, contamination, flooding, other aspects of weather, falling objects, equipment failure, emergency maintenance, employee error, arid, hypothetically, dust contamination. The chief constituents of dust storms are nonconducting clay dust (usually quartz) and conducting gypsum (calcium sulphate) which can contaminate the insulators. This contamination increases the probability of flashover, especially with fog or dew, by disclosing the salts to form an electrolyte.

However, dust buildup is reduced by the self-clearing action of the" "VI"'string insulator configuration used in EHV line construction and by the abrasive action of the dust and sand.

Also, any adverse conditions resulting from insulator contamination within the switchyard can be corrected by washing the insulators.

APS has never experienced a flashover in any of its EHV switchyards due strictly to dust on insulators and has found that dust storms contribute little to the outage frequency of EHV transmission lines.

Likewise, APS has not experienced any known dust-caused insulation failures at the 15 kV or 4 kV voltage levels in ei'ther'open substation facilities or enclosed switchgear.-

Therefore, it is felt that dust loading on the 13.8 kV system will not be a problem. The system is designed such that, with rare exceptions, forced outages do not result in.loss of load..

Other forms of contamination that increase the probability of flashover in certain areas, especially near the Pacific coast, are sea-salt deposits and industrial contaminations. The insulators can become contaminated by the salt deposits and June 2003 8. 2-9 Revision 12

PVNGS UPDATED FSAR OFFSITE POWER SYSTEM when fogging conditions exist, flashovers are more likely to occur.

To minimize the effect of both salt and industrial contamination, the insulators are washed with demineralized water. The frequency of washing depends on the area. Some areas near the Pacific Coast require washing once a month while areas farther inland require washing every 90 days. The use of semi-conducting glazed insulators also reduces the flashover rates in areas' of high contamination. No washing of insulators is anticipated in the desert regions.

June 2003 8.2-10 Revision 12

10 CFR Ch. i(i-19 Pt. 50, App. A

,r .. kdaory Commission Anticipated OPerional cecu ated operational 0 TTnes'. -out the unit, particularly in loca- rations which can result in conditions ex-onditions Of normalOcrene l cd as the containment and control ceeding specified acceptable fuel design lim-ected to occur one or inc jre detection and fighting systems of its are not possible or can be reliably and fe of the nuclear Power ure timesdn A- ate capacity and capability shall be readily detected and suppressed.

-enot lImited to loss ofnpt and lnc'ed eand designed to milhinize the ad- Criterion13-Instrumentatfon and control. In-latlon pumps, tripping of the to kal Beifects of fires on structures, systems, strumentation shall be provided to monitor

• ator set, isolation of the main turie - mponents important to safety. Fire- variables and systems over their anticipated id loss of all otfslte pow er malnden l~r systems shall be designed to assure ranges for normal operation, for anticipated l l rupture or Inadvertent operation operational occurrences. and for accident C~rrERUI o significantly impair the safety ca- conditions as appropriate to assure adequate t of these structures, systems, and safety, including those variables and systems

1. Overall Requfreents

'rlsehlOn i--Qualify Standrad are e

' IPoflen i-Environmental and dynamic ef- that can affect the fisslon process, the Integ-rity of the reactor core, the reactor coolant ructures. systems, and components gdesign bases- Structures, systems, and pressure boundary, and the containment and cat to safety shall be d POefa o Qpponents important to safety shall be de- its associated systems. Appropriate controls

)ctedf and tested to . Pged to accommodate the effects of and to zognied cdes ndquaity, qanCtidt 8 lt standaids eandr Coy. shall be provided to maintain these variables ompatible with the environmental condl-Induti with the ImPortance of the at Pons associated with, normal operation, and systems within prescribed operating Ictouns to be performed Where set ranges.

Vsintenance. testing, and postulated acci-agnied codnens and standard, ar ased, -dents. including loss-of-coolant accidents. Criterion 14-Reactor coolant pressure bound-Jy shall be Identified and evaluated to de- ary. The reactor coolant pressure boundary mine their applicability adequacy.ant these structures, systems, and components hpill be appropriately protected against iy- shall be designed, fabricated, erected, and nciency and shall bt supplemented Or lamic effects, including the effects of mis- tested so as to have an extremely low prob:

difled as necessary toeassur oa siles. pipe whipping, and discharging fluids, ability of abnormal leakage, of rapidly prop-duct in keeping with the requiredsfty that may result from equipment failures and agating failure, and of gross rupture.

action A quality establisbed assurance PrOgrn

t. from events and conditions outside the nu- Criterion 15-Reactor coolant system design.

and Implemented In order to vide adequate assurance that these struc_ elear power unit. However, dynamic effects The reactor coolant system and associated 5n, systems. and components will satinrac. associated with postulated pipe ruptures In auxiliary, control, and protection systems JlY Perform their safety-functiOns- Appro puclear power units may be excluded from shall be designed with sufficient margin to ite records Of the design, fabrication, the design basis when analyses reviewed and assure that the design conditions of the reac-Wton. and testing of structures sstm approved by the Commission demonstrate that the probability of fluid system piping tor coolant pressure boundary are not ex-components important tp saey shaiem ceeded during any condition of normal oper-ntind bry or under the control of the rapture is extremely low under conditions consistent with the design basis for the pip- ation, Including anticipated operational oc-lerpwer unit licensee throughout the- Ing. currences.

Of the unit. Criterion 5-Sharing of structures, systems. Criterion 16-Containment design. Reactor iterion 2-Desig, bases for protectio and components. Structures, systems, and containment and associated systems shall be nst natural Phenomena. Structures, Sys- components Important to safety shall not be provided to establish an essentially leak-

nonizYed prodecin 8tutres

3. and component imnportant to renerii safety shared among nuclear power units unless it tight barrier against the uncontrolled re-I be designed to withstand the effects of can be shown that such sharing will not sMg- lease of radioactivity to the environment ral Phenomena such as earthquakes. tor. nlficantly impair their ability to perform and to assure that the containment design

,es. hurricanes, floods, tun1ami, and' their safety functions, including, in the conditions Important to safety are not ex-1eeawithout lossof`Capability to perform event of an accident in one unit, an orderly ceeded for as long as postulated accident

• safety functions. The design bases for shutdown and cooldown of the remaining conditions require.

3 structures. systems, and components units.

reflect: (1) Appropriate consideration of Criterion 17-Electric power systems. An on-Most severe of the natural phenomena 11. Protectionby Multiple FissionProduct site electric power system and an offslte have been historically reported for the Barriers electric power system shall be provided to and surrounding area, with sufficient permit functioning of structures, systems, Criterion 10-Reactor design. The reactor and components important to safety. The In for the limited accuracy, quantity. core and associated coolant, control. and

?eriod of time In which the historical safety function for each system (assuming protection systems shall be designed with the other system is not functioning) shall be have been accumulated. (2) appropriate appropriate margin to assure that specified inatiObs of the effects of normal and ac- to provide sufficient capacity and capability acceptable fuel design limits are not exceed- to assure that (1) specified acceptable fuel t conditions with the effects of the flat- ed during any condition of normal operation, phenomena and (3) the importance of including the effects of anticipated oper- design limits and design conditions of the re-J.ety functions to be performed. ational occurrences. actor coolant pressure boundary are not ex-

,omn 3 -Fire Protection. Structures, sys- Criterion 1i-Reactor inherent protection. ceeded as a result of anticipated operational and components important to safety The reactor core and associated coolant sys- occurrences and (2) the core is cooled and tems shall be designed so that in the, power containment integrity and other.vital func-tentwit othr sfetyreqireents, Operating range the net effect of the prompt tions are maintained In the event of postu-Inherent nuclear feedback characteristics lated accidents.

Noncmbusibleand eat esitant tends to compensate for a rapid Increase In The onsite electric power supplies, includ-lalsshall beuse wheeverpratical reactivity. ing the batteries, and the onsite electric dis-Criterion12-Suppression of reactor power os- tributlon system, shall have sufficient inde-ered in designing the system against a cillaffons. The reactor core and associated pendence, redundancy, and testability to per-failure are under development. coolant, control. and protection systems form their safety functions assuming a sin-shall be designed to assure that power oscil- gle failure.

819

Pt. 50, App. A 10 CFR Ch. 1(1-103 Edi lear Regulatory Coff Electric power from the transmission net- cluding necessary instrumentati e used to the extent prac work to the onsite electric distribution sys- trols to maintain the unit in a s *tsof 1the protection functic tem shall be supplied by two physically inde- during hot shutdown, and (2) with i cxiteinon 23-Protectionsyst pendent circuits (not necessarily on separate capability for subsequent cold Ibe protection system shat rights of way) designed and located so as to the reactor through the use of suitabe Ztil into a safe state or In minimize to the extent practical the likell- cedures. -Cstrated to be acceptable 0:

hood of their simultaneous failure under o,- Applicants for and holders of constructl i ined basis if conditions suc erating and postulated accident and environs permits and operating licenses undert',J4 Mtion of the system, loss of e mental conditions. A switchyard common to part.who apply on or after January 10, igt *tric power. instrument air), £ both circuits Is acceptable. Each of these cir- applicants for design certifications weir verse environments (e.g., e cuits shall be designed to be available in suf- part 52 of this chapter who apply On Or ij cold. rare, pressure, steam, flcient time following a loss of all onsite al- January 10, 1997, applicants for and boljA ition) are experienced.

ternating current power supplies and the of combined licenses under part 52 orU4s . Criterion 24-Separation oj other offsite electric power circuit, to assure chapter who do not reference a standar by, control systems.. The protecti that specified acceptable fuel design limits sign certification, or holders of operati.I be separated from control sy and design conditions of the reactor coolant censes using an alternative source tio ,tent that failure of any sin pressure boundary are not exceeded. One of under 150.67, shall meet the requiremelati'b *tem component or channel, these circuits shall be designed to be avail- this criterion, except that with regarde16 .noval from service of any s able within a few seconds following a loss-of- control room access and occupancy ;s& system component or chann, coolant accident to assure that core cooling, quate radiation protection shall be profidid aon to the control and pro containment integrity, and other vital safe- to ensure that radiation exposures shail ' leaves intact a system sat ty functions are maintained. exceed 0.05 Ev (5 rem) total effectiveioW, ability, redundancy, and ir Provisions shall be Included to minimize equivalent (TEDE) as defined In S50.2 for X. quirerments of the protectio2 the probability of losing electric power from duration of the accident. i. connection of the protection any of the remaining supplies as a result of, tes shall be limited so a.

or coincident with, the loss of power gen- 111. Protectionand Reactivity Control Sysleng safety is not significantly Im erated by the nuclear power unit. the loss of Criterion 20-Protection system funcho@. CNterion 25-Protection sys power from the transmission network. or the .for reactivity control malfunct The protection system shall be designedi) Stfon system shall be designe loss of power from the onsite electric power to initiate automatically the operation'o supplies. specified acceptable fuel de appropriate systems Including the renichid mot exceeded for any single Criterion18-Inspection and testing of electric control systems, to assure that specids6d'-

power systems. Electric power systems impor- the reactivity control syster ceptable fuel design limits are not exceM. Aentalwithdrawal (not eject tant to safety shall be designed to permit ap- as a result of anticipated operational occii.

propriate periodic Inspection and testing of Letcontrol rods.

rences and (2) to sense accident conditfion , Critexion 26-Reactivity cont Important areas and features, such as wiring, and to initiate the operation of systemnsiA :dancy and capability. Two In Insulation, connections, and switchboards, to components important to safety.

assess the continuity of the systems and the MVty control systems of Criterion 21-Protection system rellabilifla principles shall be provided.

condition of their components. The systems testability. The protection system shall bde tens shall use control rod.

shall be designed with a capability to test signed for high functional reliability Sa eluding a positive means fc periodically (1) the operability and func-. service testability commensurate with*. rods, and shall be capable of:

tional performance of the components of the safety functions to be performed. Go:-' hog reactivity changes to al systems. such as onsite power sources, re- dancy and Independence designed Inty'1h ;qndtlons of normal opera lays, switches, and buses, and (2) the oper- protection system shall be sufficient a iaticipated operational oc ability of the systems as a whole and. under sure that (1) no single failure results l Mith appropriate margin fc conditions as close to design as practical, the of the protection function and (2) rem0$f Arch as stuck rods, specified full operation sequence that brings the sys- from service of any component or ch .

1. 41sgn limits are not excee(

tems into operation, Including operation of does not result in loss of the requke . itactivity control system sh.

applicable portions of the protection system, Imum redundancy unless the acceptable ?eliably controlling the rat and the transfer of power among the nuclear ability of operation of the protection BYE *anges resulting from p power unit. the offsite power system. and the can be otherwise demonstrated. The PrS~j er changes (including xe.

onsite power system. tion system shall be designed to petni~h Asre acceptable fuel desigi Criterion 191-Control rooan. A control room odic testing of its functioning when th&a tZceeded. One Of the system shall be provided from which actions can be tor is In operation, Including a capabi Ale of holding the reactor taken to operate the nuclear power unit safe- test channels Independently to de Paler cold conditions.

ly under normal conditions and to maintain failures and losses of redundancy ~Cfleriteon 27-Corbined react It In a safe condition under accident condi- have occurred. MPS Capability. The reactive tions, Including loss-of-coolant accidents. Criterion 22-ProtectiOn system shall be designed to h Adequate radiation protection shall be pro- The protection system shall be desiib gPability in conjunction w vided to permit access and occupancy of the assure that the effects of Mat r by the emergency core control room under accident conditions nomena. and of normal operating Go E reliabiS controlling reacti without personnel receiving radiation expo- nance, testing, and postulated acci i Ure that under postulated.

sures in excess of 5 rem whole body, or its ditions on redundant channels do n Ls and with appropriate n equivalent to any part of the body, for the in loss of the protection function, o g the capability to cool tI duration of the accident. Equipment at ap- demonstrated to be acceptable on Ztd propriate locations outside the control room defined basis. Design techniQues gC~lerlon 25-Reactidity hin shall be provided (1) with a design capability functional diversity or diversitY systems shall I for prompt hot shutdown of the reactor, in- nent design and principles Of operaf i .

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