ML19260D387

Forwards Info Re Short Term Recommendations & Emergency Feedwater Sys Flow Requirements in Response to NRC 791106 Request Re Emergency Feedwater Sys

ML19260D387
Person / Time
Site:	Arkansas Nuclear
Issue date:	01/31/1980
From:	Trimble D ARKANSAS POWER & LIGHT CO.
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
2-010-24, 2-10-24, NUDOCS 8002080647
Download: ML19260D387 (17)

Text

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1 ARKANSAS POWER & LIGHT COMPANY POST OFFICE BOX SS1 LITTLE ROCK. ARKANSAS 72203 (501) 371-400f, January 31, 1980 2-010-24 Director of Nuclear Reactor Regulation ATTil: far. Darrell G. Eisenhut, Acting Director Operating Reactors U.S. Nuclear Regulatory Commission Washington, D. C. 20555

Subject:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Emergency Feedwater System (File: 2-1510.1)

Gentlemen:

In response to your letter of fiovember 6,1979, pertaining to the Emergency Feedwater System for Arkansas Nuclear One - Unit 2, the attached information is provided.

More specifically, Attachment i addresses your recommendations in enclosure 1 and Attachment 2 add: .sses your enclosure 2.

For future reference, the actuation system for emergency feedwater on Unit 2 is the Emergency Feedwater Actuation System (EFAS) not the Engineered Safety Actuation System (ESFAS).

Very truly yours,

.D& 0 f David C. Trimble 14anager, Licensing DCT:DEJ:nak Attachments

.. I 1934 209 8002080 6E7 ;

__mem s_mme s s1. I

b Attachment i I

X.1.3 Recommendations for this Plant The short-term recommendations (both generic, denoted by GS, and plant-specific) identified in this section represent ac-tions to improve AFW system reliability that should be im-plemented by January 1,1980, or as soon thereafter as is practicable. In general, they involve upgrading of Technical Specifications or establishing procedures to avoid or mitigate potential system or operator failures. The long-term recommenda-tions (both generic, denoted by GL, and plant-specific) identi-fied in this section involve system design evaluations and/or modifications to improve AFW system reliability and represent actions that should be implemented by January 1,1981, or as soon thereafter as is practicable.

X.1.3.1 ShortTerm

1. Recommendation GS 6 - The licensee should confirm flow path availability of an AFW system flow train that has been out of service to perform periodic testing or maintenance as follows:

. Procedures should be implemented to re-quire an operator to determine that the AFW system valves are properly aligned and a second operator to independently verify that the valves are properly aligned.

. The licensee should propose Technical Specifications to assure that prior to plant startup, following an extended cold shutdo., ., a flow test would be performed to v-..iy the normal flow path from the primary AFW system water source to the steam generators. The flow test should be conducted with AFW system valves in their normal alignment.

Response

The first section of this recommendation was previously addressed by Arkansas Power and Light Company in our response to question 7 of IE Bulletin 79-06B, dated August 16, 1979.

Question 7 of IE Bulletin 79-06B was stated as follows:

7) Review all safety-related valve positions, positioning requirements and positive controls to assure that valves remain positioned (open or closed) in a manner to ensure the proper operation of engineered safety features. Also, review related procedures, such as those for maintenance, testing, plant and system startup, and supervisory, 1934 210

periodic (e.g., daily / shift checks) surveillance to ensure that such valves are returned to their correct positions following i necessary manipulations and are maintained in their proper posi-tions during all operational modes.

Our response to question 7 was as follows:

We have completed a review of the Engineered Safety Feature (ESF) valves and their positioning requirements. The ESF systems are:

a) Containment Isolation System (CIS) b) Containment Spray System (CSS) c) Containment Cooling System (CCS) d) Safety Injection System (SIS) e) Penetration Rcom Ventilation System (PRVS) f) Main Steam Isolation System (NSIS) g) Emergency Feedwater System (EFS) h) Chemical and Volume Control System (CVCS) i) Diesel Fuel Oil and Starting Air System j) Emergency Boration Systems k) Service Water Based on this review, and our_ review of related procedures, we have concluded that our procedures are adequate to ensure that valves in ESF systems are maintained in their proper position, or are capable of being properly positioned in the event of an Engineered Safety Feature Actuation Signal (ESFAS).

The procedures reviewed are summarized as follows:

Maintenance Prior to taking an ESF system out of service, the Control Room must be notified as required by procedure. The re-dundant train of the affected ESF system will be inspected to verify operability prior to taking the aforementioned system out of service. The inspection will include checking control board in-dications, MOV status, alarm status, and verification that the last surveillance test was within the surveillance interval and dem-onstrated operability. The out-of-service system includes com-ponents for which maintenance is to be performed as well as the valve (s) used to isolate the component for maintenance. Tags are placed on the affected out-of-service equipment, both at the equip-ment proper and at Motor Control Center (MCC) breakers, if appli-cable. Additionally, the out-of-service equipment is entered into the station log. Following completion of maintenance, and removal of out-of-service tags, the system is realigned to its proper con-figuration by the operator, the Control Room is notified of system return to service, and entry is made in the station log. Surveil-lance tests are performed to verify the operability of the affected equipment.

Testing All ESF systems are required by ASME Section XI and/or ANO-2 Technical Specifications to be tested to ensure operability.

Test frequencies vary according to the component being tested, and

~~

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the reason for testing. Upon completion of ESF system testing, for whatever reason, the subject system is verified as required by procedure to be properly aligned to allow the system to perform its safety function. The verification of lineup is done by the opera-tor using sign-offs in the procedure.

During our review, all manually operated valves were found to be procedurally required to be in their correct position. The proce-dures further require the system lineups to be verified correct prior to declaring the system operable. However, several of these valves in systems not classified as ASME Codes 1, 2, or 3 were not subject to the " Category E" listing (i.e., required to be locked, sealed or otherwise secured in their proper position). These valves, in the Diesel Fuel Oil System and Diesel Starting Air System, though not classified as Class 1, 2, or 3 will be added to the " Category E" procedure list and, as such, are required to be and will be locked, sealed, or otherwise secured in their proper position during operation, thus further assuring proper valve positioning of all safety-related valves in their associated system.

These procedural changes will be implemented by June 1,1979.

Thus, based on procedural controls and this review, we feel assured that all safety-related valves are positioned in, or are capable of being positioned in their ESF position upon receipt of an ESFAS, thereby ensuring the required response of systems to postulated events.

Startup - All safety-related systems are required to be operable (valves in the correct position) prior to and/or during plant startup as appropriate.

To address the second part of this recommendation, the following is provided:

The ANO-2 motor driven emergency feedwater pump is designed to supply condensate to the steam generators during plant startup. By supplying the feedwater to the steam generators during startup, this assures the normal flow path of the B EFW train from the primary EFW system water source to the steam generators is available prior to operations follow-ing an extended cold shutdown.

We will evaluate a proposed Technical Specification to assure that, following a refueling outage and once sufficient steam is available, a flow test would be performed for the steam driven EFW pump. This test would verify the normal flow path of the A EFW train from the primary EFW system water source to the steam generators. The results of this evaluation will be provided by March 1, 1980.

2. Recommendation GS 7 - The licensee should verify that the automatic start AFW system signals and associated circui-try are safety-grade. If this cannot be verified, the AFW system automatic initiation system should be modified in the short-term to meet the functional requirements listed below.

_3 1934 212

For the longer term, the automatic initiation sig-nals and circuits should be upgraded to meet safety-grade requirements as indicated in Recommendation GL-5.

. The design should provide for the automatic ini-tiation of the auxiliary feedwater system flow.

. The automatic initiation signals and circuits should be designed so that a single failure will not result in the loss of auxiliary feedwater system function.

. Testability of the initiation signals and circuits shall be a feature of the design.

. The initiation signals and circuits should be power-ed from the emergency buses.

. Manual capability to initiate the auxiliary feed-water system from the control room should be re-tained and should be implemented so that a single failure in the manual circuits will not result in the loss of system function.

. The alternating current motor-driven pumps and valves in the auxiliary feedwater system should be included in the automatic actuation (simultaneous and/or sequential) of the loads to the e:nergency buses.

. The automatic initiation signals and circuits shall be designed so that their failure will not result in the loss of manual capability to initiate the AFW system from the control room.

Response

The existing ANO-2 EFW system meets your recommendations.

3. Recommendation - The Surveillance Requirements section of the Technical Specifications should add pressure and flow acceptance criteria for the periodic (31-day) testing of the motor driven pumps.

Response

The motor driven emergency feedwater pump for AN0-2 is a ASME Code Class 3 component which is required to meet surveillance requirement 4.0.5 of AN0-2's Technical Specifications. This specification requires that all ASME Code Class 1, 2, and 3 pumps shall be tested in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable addenda as required by 10 CFR 50, Section 50.55a(g), except where speci-fic written relief has been granted by the Commission pursuant to 10 CFR 50, Section 50.55a(g)(6)(i).Section XI of the ASME Boiler and Pressure Vessel Code specifies acceptance criteria for pressure and flow rates.

1934 213

X.1.3.2 Additional Short-Term Recommendations The following additional short-term recommendations resulted from the staff's Lessons Learned Task Force review and the Bulletins and Orders Task Force review of AFW systems at Babcock & Wilcox designed operating plants subsequent to our review of the AFW system designs at W and C-E designed operating plants. They have not been examined for specific applicability to this facility.

1. Reconnendation - The licensee should provide redundant level indications and low level alarms in the control room for the AFW system primary water supply to allow the operator to anticipate the need to make up water or trans-fer to an alternate water supply and prevent a low pump suction pressure condition from occur-ring. The low level alarm setpoint should allow at least 20 minutes for operator action, assuming that the largest capacity AFW pump is operating.

Response

Redundant means of determining if sufficient coolant is available to the EFW pumps through the condensate storage tank are provided by safety-grade pressure switches located in the suction piping to the EFW pumps, as shown ir figure 10.4-2 of the Unit 2 FSAR. Should the pressure at either of these switches drop to 7 (+1, -0) psig, from its normal 10 psig, local and control room alarms will be actuated. If the pressure drops to 5 (+1, -0) psig, the pressure switch will automatically close the affected condensate line isolation valves and will simultaneously open suction to the service water system.

2. _ Recommendation - The licensee should perform a 72-hour endurance test on all AFW system pumps, if such a test or continuous period of opera-tion has not been accomplished to date. Fol-lowing the 72-hour pump run, the pumps should be shut down and cooled down and then restarted and run for one hour. Test acceptance criteria should include demonstrating that the pumps remain within the design limits with respect to bearing / bearing oil temperatures and vibration and that pump room ambient conditions (tempera-ture, humidity) do not exceed environmental qualification limits for safety-related equip-ment in the room.

Response

During hot functional testing of Unit 2, the motor driven EFW pump was used to supply condensate to the steam generators. In order to supply 1934 214

sufficient condensate during those tests, the motor driven pump was required to function continuously for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. While operating during this test, the pump remained within the design limits with respect to bearing / bearing oil temperature and vibration and one pump room ambient conditions did not exceed environmental qualification limits.

Arkansas Power and Light will perform the recommended 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> endurance test, as outlined in your letter of December 13, 1979, on the steam driven EFW pump. This test will be conducted following the current outage for Unit 2.

3. Recomendation - The licensee should implement the following requirements as specified by Item 2.1.7.b on page A-32 of NUREG-0578:

" Safety-grade indication of auxiliary feedwater flow to each steam generator shall be provided in the control room.

The auxiliary feedwater flow instrument chan-nels shall be powered from the emergency buses consistent with satisfying the emergency power diversity requirements for the auxiliary feed-water system set forth in Auxiliary Systems Branch Technical position 10-1 of the Standard Review Plan, Section 10.4.9."

Response

The ANO-2 EFW system currently meets these recommendations.

4. Recommendation - Licensees with plants which require local manual realignment of valves to conduct periodic tests on one AFW system train, and there is only one remaining AFW train available for operation should propose the Technical Specifications to provide that a dedicated individual who is in communication with the control room be stationed at the manual valves. Upon instruction from the control room, this operator would realign the valves in the AFW system train from the test mode to its operational alignment.

Response

The AN0-2 EFW system does not require local manual realignment of valves to conduct periedic tests.

X.1.3.3 Long-Term Long-term recomendations for improvir- the system are as follows:

1934 215

1. Recommendation - GL The licensee should upgrade the AFW system automatic initiation signals and circuits to meet safety-grade requirements.

Response

The AN0-2 EFW system currently meets this recommendation.

2. Recommendation - The Arkansas Unit 2 AFW system design does not meet the high energy line break criteria in SRP-10.4.9 and Branch Technical Position 10-1; namely, that the AFW system should requiredmaintain AFW flowthe capability to the to supplys) steam generator (the assuming a pipe break anywhere in the AFW pump discharge lines concurrent with a single active failure.

The licensee should evaluate the postulated pipe breaks stated above and (1) determir.e any AFW system design changes or procedures neces-sary to detect and isolate the break and direct the required feedwater flow to the steam gen-arator(s) before they boil dry or (2) describe how the plant can be brought to a safe shutdown condition by use of other systems which would be available following such postulated events.

Response

If t"h EFW trains for ANO-2 were rendered inoperable, the operators would follow Emergency Operating Procedure 2202.06, Revision 1, dated 12/20/79,Section II 3.5. According to this procedure, once the operator recognizes that the RCS pressure is increasing in a saturated condition and RCS temperature and pressure are greater than secondary pressure and temperature, he..t transfer to the secondary system via natural circula-tion or re-condensation plus HPSI flow is not sufficient for core cool-ing, he should open the pressurizer ECCS vent valves 2CV-4697-2 and 2CV-4698-1 to lower RCS pressure and provide greater HPSI flow. This ECCS vent line is sufficient to remove decay heat. Thus, the HPSI and LPSI system can be used to cool the core.

3. Recommendation - Concern was expressed to the licensee about the capability of the design to isolate a break occurring downstream of the steam admission valve to the turbine-driven pump during AFWS operation concurrent with a single active failure c. the DC emergency Division II.

Assuming th e without DC, the corresponding diesel c nerator will not be able to start, the break could not be isolated because of the loss of OC and AC power in Division II. The licensee .

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advised that analysis has been performed show-ing that there is sufficient residual magnetism to flash the diesel generator field and conse-quently the Division II diesel generator can be brought up to speed and voltage without the need of DC from the emergency batteries. Thus, the break could be isolated if the failure of the DC emergency Division II does not result also in the loss of AC in the same division.

The licensee should submit for staff review the analysis with regard to starting the diesel generator without DC emergency power available.

Response

DC flashing of the generator field is not essential for the generator to develop rated voltage. It simply accelerates the time in which the generator develops rated voltage.

The ANO-2 Diesel Generator manufacturer has indicated that reaching full voltage depends upon the rate of acceleration to rated diesel engine speed. Their experience has shown that without DC flashing the gene-rator will reach full rated voltage in 5 9.5 seconds, within the ANO-2 acceptance criteria.

1934 217

Atta.nment 2 BASES FOR E!1ERGEtlCY FEEDWATER SYSTE!! FLOW REQUIREl1EllTS Desian Bases for EFS Punp Capacity The design base requirement for Energency Feedwater System (EFS) pump capacity, as stated in FSAR Section 10.4.9 is that each pump must be capable of delivering sufficient energency feedwater to the stean generator (s) to preserve their function as a secondary heat sink for normal shutdowns and the pumo must also provide sufficient feedwater in combination with pressurizer sprays or the' RCS safety valves to preclude overpressurization of the RCS for feedwater line break accidents.

Emergency Feeduater Puno Desinn Point Based on the above requirenents, the following conditions were used to size each EFS pump.

1. Steam generator water level is to be naintained when either steam generator is being used to renove up to 2.95;; full power in decay heat.

2. The naximun stean generator pressure against which the EFS punp must provide sufficient flow is 1220 psia, which is 110% of the steam generator design pressure.

3. Suction pressure available to the EFS pump corresponds to the one foot water level in condensate storage tanks 2T41A or B.

4 Each EFS pump recirculation line capacity is a maxinun of 75 gpn.

5. The maximun energency feedwater temperature is 100 F.

p The resulting rating of each EFS pump is 575 gpm at 2000 ft. The net flow rate supplied to either stean generator is 500 gpm at 1220 psi. For conservatism, 285 gpn is used in analyses as the nininum EFS flowrate to either steam generator. The 485 gpn flow rate is the assuned EFS flow rate for the FSAR Chapter 15 Safety Analyses.

1934 218

f. 11axinum pressure at which steam is released for steam tenerator(s) -

anu against which the ARI pump nust develop sufficient head.

Each Enl will develop sufficient head against a pressure of 1220 psi which is 110 percent of steam generator design pressure.

9 11ininun number of steam generators that must receive ARl flow; e.g.

1 out of 2?, 2 out of 4?

9 Only one of two steam generators is required to assure adequate removal of decay heat during all plant accident and operating conditions.

h. RC flow condition - continued operation of RC punps or natural circulation.

For the feedwater line break cases, reactor coolant pumps are assumed operating except when offsite AC power is unavailable. During plant cnoldown, reactor coolant pumps are assumed operating.

i. Ilaxinum ARI inlet temperature.

The naxinum EFS inlet tenperature is assuned to be 100 F.

j. Followingapostulatedsteamorfeedlinebreak,tinedeSayassumed to isnlate break and direct ARI flow to intact stean generator (s).

ARl punp flow capacity allowance to accommodate the time delay and naintain minimun steam generator wate.r level. Also identify credit taken for primary system heat removal due to bloudown. -

For the main feedwater line break analysis (FSAR, 15.1.14), the conditions necessary to identify and isolate the affected steam generator occur at 57.6 seconds subsequent to the initiation of the event. EFil flow enters the intact stean generator at 123.5 seconds, flo credit was taken for primary heat removal due to blowdown.

k. Volune and maximum temperature of water in nain feed lines between stean generator (s) and ARIS connection to nain feed linpC)} 4 2 } 9 Initial main feeduater temperature is assumed to be 452 F, which

cnrresponds to full load plant conditions. For the feedwater line break case, main feedwater flow is assumed to be automatically reduced to zero percent in 20 seconds. When EFW flow is assumed to enter the steam generator no credit is taken for the volume of feedwater that

- would normally be available in the feedline between the steam generator and the EFU system convection. ,

1. Operating condition of steam generator normal blowdown following initiating event.

Stean generator normal blowdown is not considered subsequent to the initiating event. During plant accident conditions blowdown is isolated upon a nain steam isolation signal (f1 SIS) resulting from low steam generator pressure,

m. Primary and secondary system water and netal sensible heat used for cooldown and AFW flow sizing.

6 1.54 x 10 BTU / F

n. Tine at hot standby and tine to cooldown RCS to RHP, system cut in temperature to size AFW water source inventory.

The condensate storage tank water volune is adequate to enable one hour of hot standby operation followed by a three to four hour plant cool-down to sh'utdown cooling systen initiation tenperature.

3. Verify that the AFW pumps in your plant will supply the necessary flow to the stean generator (s) as detemined by items 1 and 2 above considering a single failure. Identify the margin in sizing the pump flod to allow for pump recirculation flow, seal leakage and pump wear.

The EFU system will supply the necessary flow to naintain the function of the steam generators as effective heat sinks. Each EFU pump can provide the required system flowrate to either stean generator. Redundant valves, piping, pumps, and control systems and diverse conpucent power supplies ensure that given a single failure, sufficient feedwatt:r is supplied ~

to the steam generators. FSAR Table 10 A-11 and Appendix 3A provide additional information with respect to the ability of the EFS to perform its design function in the event of a single failure.

The allowance for EFW pump recirculation is 75 gpn per pump.

4 220

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. The reactor power, including instrument error, at the time of the initiating event is conservatively assumed to be 2900 !!Wt, which is 103 percent of licensed core power.

b. Tine delay from initiating event to recetor trip. ,

For the main feedline break case, 58.5 seconds is assumed.

c. Plant paraneter(s) which initiates AFWS flow and time delay between initiating event and introduction of AFWS flow into steam generator (s).

Low steam generator level coincident with no iow pressure trip present and low stean generator level coincident with a differential pressure between the two steam generators, with the higher pressure steam gen-erator..being ' feed, are the parameter which automatically initiates EFW flow. For the main feedwater line break case, EFW flow is assumed to enter the intack steam generator at 123.5 seconds.

d.  !!inimum stean generator water level when initiating event occurs.

For the feeduater line break case, the initial steam generator inventory is 181610 lbm. mis corresponds to a level at the high end of the in-dicating range chosen such that reactor trip on high pressure will occur simultaneously with a reactcr trip on low steam generator level.

Such a choice assures that 1) the most limiting RCS transient prior to reactor trip ht, occurred and that 2) a. mininum socnndarv hoat sir!k.<

is assuned for the subsequent cooldown of the RCS.

e. Initial steam generator water inventory and depletion rate before and after AFUS flow comnences - identify reactor decay heat rate used.

Initial stean generator inventories and depletion rates have the greatest inpact on the feedwater line break case with' respect to assuring that 1) the most liniting RCS transient prior to reactor trip has occurred, and that 2) a worst case secondary heat sink exists for the subsequent cooldown of the RCS. Table 15.1.14-21 of FSAR Section 15.1.14 shows the generator depletion rate for the feedwater line break case. Additionally, the case nresented in Section 15.1.14 demonstrates that EFU pump capacity is sufficient in combination with either the pressurizer sprays or the RCS safety valves to prevent overpressurization of the RCS.

Once EFU flou enters the intact steam generator, sufficient EFU pump capacity exists to remove decay heat and maintain steam generator water level. 1934 222

. Requested Information Regarding Design Base Transients and Accident Conditions.

The following infomation is provided in accordance with the flRC request for additional information regarding energency feedwater systen flow requirements.

1.a. Identify the plant transient and accident conditions considered in establishing AFilS flow requirenents. .

1) Loss of liain Feedwater (Lf1Fil)

Although not a design base event for detemining EFS pump capacity, the adequacy of EFS flow to maintain steam generator heat renoval capability is shown by FSAR analysis 15.1.8.

2) LI-1Fil with loss of offsite AC power.

Although not a design base event for determining EFS flowrate re-quirements, the adequacy of available EFS flow is shown by FSAR analysis 15.1.9.

3) Ll1Fil with loss of onsite and offsite AC power.

Although not a design base event for detemining EFS punp capacity, the required flow rate is the same as that for a LliFil uith loss of offsite AC power. In the remote case of failure of nomal, perferred and energency electrical power, the required flow is delivered by the turbine driven EFS pump.

4) Plant Cooldown.

• Asa design base event for sizing the EFil cumps, each EFl! punp has sufficient capacity to ensure adequate flow to naintain stean generator water level when either stean generator is being used to remove reactor decay heat, RCP heat, and primary and secondary systen water and metal sensible heat. These requirements are illustrated in Figure 1.

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5) Turbine Trip Uith and Without Bypass.

Although not a design base event for dctermining EFS pump capacity, the adequacy of EFS flow for turbine trip without bypass is shown by FSAR Analysis 15.1.7. A turbine trip with the steam bypass system available will not result in actuation of the EF5.

6) Main Steam Isolation Valve Closure.

This event is enveloped by the loss of main feedwater event discussed in FSAR Analysis 15.1.8.

7) Main Feedline Break.

As a design base event for sizing the EFW pumps, the cases in FSAR Section 15.1.14 denonstrate that the capacity of each EFW pump is sufficient in conbination with either the pressurizer sprays if AC power is available,or the RCS safety valves if AC power is lost,to prevent overpressurization of the reactor coolant system.

8) Main Steam Line Break.

Although not a design basis for determining EFS pump capacity, FSAR Section 15.1.14 verifies that EFW pump capacity is adequate to maintain a water level' in the intact steam generator during the transient, thus preserving the secondary heat sink.

9) Snall Break LOCA.

Although not a design basis event for determining EFS pump capacity, analysis of this event shows that the EFU systen will maintain sufficient mass in the stean generator (s) to maintain.them as effective heat sinks.

10) Other transient or accident conditions not listed above.

a) Plant Startup EFS flow requirement is less than that required for plant cooldown.

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b) Hot standby and hot shutdoun Although not a design base event for detennining EFS pump capacity, the EFil system is placed in operation to maintain steam generator water level. Pump flow requirement is less than that required for plant cooldown.

1.b. Describe the plant protection acceptance criteria and corresponding technical bases used for each initiating event identified above.

1) flain Feedline Break Criteria -

a) The RCS pressure does not exceed 110 percent of the design value, b) The DNBP, in the limiting coolant channel in the core shall not be less than 1.3.

c) The peak local power density in the limiting fuel pin in the core shall not be sufficient to initiate centerline fuel nelting.

There are no specific cooldown rates or stean generator water level acceptance criteria for this event.

2) Plant Cooldown.

a) Steam generator nornal water level is naintained in either steam generator until RCS temperature is cooled to 350 F and shutdown cooling has been initiated, b) RCS Cooling rate is limited to no more than 100 F per hour based on thermal stress considerations.

c) Maximum RCS pressure does not exceed the tenperature dependent Technical Specification limits based on low temperature over-pressure protection.

2. Describe the analyses and assumptions and corresponding technical justi-fication used with plant conditions consi.iered in 1.a above includina:

a. flaxinun reactor power (including instrument error allowance) at the tine of the initiating transient or accident.

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