ML20044G289

Forwards Response to Inquiries Re Amend 27 Covering Suppression Pool Cooling

ML20044G289
Person / Time
Site:	05200001
Issue date:	05/21/1993
From:	Fox J GENERAL ELECTRIC CO.
To:	Poslusny C Office of Nuclear Reactor Regulation
References
NUDOCS 9306020279
Download: ML20044G289 (4)

Text

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GE Nuclear Energy

-:"s c.m A.we w xc [A 95:n May 21,1993 Docket No. STN 52-001' I

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Chet Poslusny, Senior Project Manager Standardization Project Directorate Associate Directorate for Advanced Reactors and License Renewal Office of the Nuclear Reactor Regulation

Subject:

Submittal Supporting Accelerated ABWR Review Schedule - Inquiries Pertaining to Amendment 27

Dear Chet:

Responses to George Thomas pertaining to Amendment 27 are provided below:

(1)

The suppression pool cooling has changed from manual to automatic. Herefore, the information previously as manual under Subsection 5.4.7.2.6 (3) has been moved to Subsection 5.4.7.1.1.5 as automatic. The redundant information on page 5.4-22 will be deleted.

(2)

Subsection 7.6.1.7 is underdevelopment and will reflect automatic scram.

(3)

FPC Subsection 7.6.1.4 was deleted and relocated to Subsection 7.7.1.10 (safety to non-safety).

(4)

Two sentences of Subsection 93.5 deleted (attached).

(5)

A description of the 8 minute high drywell bypass timer has been added to Subsection 633.4 (attached).

Please provide a copy of this transmittal to George Thomas.

Sincerely, W

.lack Fox Advanced Reactor Programs cc: Frank Paradiso (GE)

BillTaft (GE) l i

Norman Fletcher (DOE)

Paul Billig(GE) 0-

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e operated pump suction valves, and associated

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i the secondary containment outside the drywell and

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'l wetwell. The liquid is piped into the reactor '" '" The psmp and system design pressure j

vessel throughout the high pressure core flooder between the injection valves and the pump and (HPCF) line downstream of the HPCF inboard check system design pressure bgtween relief valves are f

vake.

approximately 110 kg/cm a. To prevent bypass l flow from one pump in case of relief valve l

The boron absorbs thermal neutrons and thereby failure in the line from the other pump, a check terminates the nuclear fission chain reaction in valve is installed downstream of each relief the uranium fuel valve line in the pump discharge pipe.

l The specified neutron absorber solution is The SLCS is automatically initiated after i

sodium pentaborate (Na B 0 H O).

receiving an anticipated transient without scram

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lt is prepared by dissolving stoichiometric (ATWS) signal or can be manually actuated by l

quantitics of borax and boric acid in deminera-either of two keylocked, spring-return switches l

lized water. An air sparger is provided in the on the control room console. This assures that j

tank for mixing. To prevent system plugging, the switching from the STOP position is a deliberate tank outlet is raised above the bottom of the act. Changing either switch status to START tank.

starts an injection pump, opens one motor-operated injection valve, opens one pump suction At all times when it is possible to make the motor-operated valve, and closes one of the l reactor critical, the SLCS shall be able to reactor cleanup system outboard isolation valves i

deliver enough sodium pentaborate solution into to prevent loss of boron.

l the reactor (Figure 9.3-2) to assure reactor shutdown. This is accomplished by placing sodium An ATWS condition exists when either of the pentaborate in the standby liquid control tank following occurs and filling it with demineralized water to at 2

least the low level alarm point. The solution (a) High RPV pressure (79.1 kg/cm g) and l l

l can be diluted with water to within 36 cm of the average power range monitor (APRM) not j

overflow level volume to allow for evaporation down scale for 3 minutes, or j

losses or to lower the saturation temperature.

(b) Low RPV level (Level 2) and APRM not

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The minimum temperature of the fluid in the down scale for 3 minutes.

tank and piping shall be consistent with that obtained from Figure 9.3-3 for the solution A light in the control room indicates that temperature. The saturation temperature of the power is available to the pump motor contactor recommended solution is 15 C at the low level and that the contactor is deenergized (pump not alarm volume and a lower temperature at 36 cm running). Another light indicates that the

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below the tank overflow volume (Figures 9.3-2 and contactor is energized (pump running).

1 9.3-3). The equipment containing the solution is' j

installed in a room in which the air temperature Storage tank liquid level, tank outlet valve l

is to be maintained within the range of 15 C to position, pump discharge pressure, and injection 38 C. An electrical resistance heater system valve position indicate that the system is provides a backup heat source which maintains the functioning. If any of these items indicates solution temperature at 24 C (automatic that the liquid may not be' flowing, the operator operation) to 30 C (automatic shutoff) to shallimmediately change the other switch to the prevent precipitation of the sodium p:ntaborate START position, thereby activating the redundant i

from the solution during storage. High or low train of the SLCS. Tbc local switch cannot temperature, or high or low liquid level, causes prevent the operation of the pump from the an alarm in the control room.

control room. Pump discharge pressure and valve status are indicated in the control room.

p,rement pump h aud ta t

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to valve motion in the case of the high pressure either the ADS initiating signal or the l

system provides a suitably conservative allowance overpressure signal opens the safety-relief l

for valves available for this application. In valve, no conflict exists.

I the case of the low pressure system. the time delay for valve motion is such that the pumps are The LPFL subsystem is configured from the RHR at rated speed prior to the time the vessel pumps and some of the R.HR valves and piping.

I pressure scaches the pump shutoff pressure.

When the reactor water level is low, the LPFL subsystem (line up) has priority through the The ADS actuation log,ic includes a 29 second valve control logic over the other RHR delay timer to confirm the presence of low water subsystems for containment cooling. Immediately level 1 (LWL 1) initiation signal. This timer is following a LOCA, the RHR system is directed to l

initiated upon receipt of a high drywc!! pressure the LPFL mode. When the RHR shutdov coelireg signal (which is sealed-in) and a LWL 1 signal. mode is utilized, the transfer to the l' mode i

The timer setting is consistent with the startup must be remote manually initiated.

time of the ECCS which also must be running before ADS operation can occur. Once the ADS 633.6 Limits on ECCS System Parameters timer is initiated, it is automatically reset if

..f the reactor water level is restored above the LWL Limits on ECCS parameters are given in the r#

1 setpoint before ADS operation occurs The ADS sections and tables refernced in Subsections x

~ control system also provides the operator with an 633.1 and 633.7.1. Any number of components ADS inhibit switch which the operator can use to in any given system may be out of service, up to prevent automatic ADS operation as covered by the the entire system. The maximum allowable engineering operating procedures. fer fu the e out-of-service time is a function of the level i

de t% rder To Sa65uten 7d.

of redundancy and the specified test intervals.

The flow delivery rates analyzed in Subsection 633 can be determined from the head. flow curves 633.7 ECCS Analyses for LOCA in Figures 6.3-4, 6.3 5 and 6.3-6 and t h e pressure versus time plots discussed in 633.7.1 LOCA Analysis Procedures and input Subsection 6.33.7. Simplified piping and Variables instrumentation and process diagrams for the ECCS are referenced in Subsection 6.3.2.

The The methods used in the analysis have been operational sequence of ECCS for the limiting approved by the NRC or meet the change criterion t

i case is shown in Table 63 2.

in 10CFR50.46. For the system res anse l

analysis, the LAMB / SCAT and SAFER /GESTR Operator action is not required, except as a models approved by the NRC were used. The monitoring function, during the short-term significant input variables used for the cooling period following the LOCA. During the response analysis are listed in Table 63-1 and long-term cooling period, the cperator may need Figure 63-11.

to take action as specified in Subsection 6.2.2.2 to place the containment cooling system into 633.7.2 Accident Description l

operation for some LOCA events.

The operation sequence of events for the 633.5 Use of Dual Function Components for limiting case is shown in Table 63-2.

ECCS 4

633.73 Break Spectrum Calculations i

With the exception of the LPFL systems, the systems of the ECCS are designed to accomplish A complete spectrum of postulated break only one function; to cool the reactor core sizes and locations were evaluated to following a loss of reactor coolant. To this demonstrate ECCS system performance. For case extent, components or portions of these systems of reference, a summary of figures presented in g

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(except for pressure relief) are not required for Subsection t@pis shown in Table 63-5.

A operation of other systems which have emergency

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core cooling functions, or vice versa. Because A summary of results of the break spectrum calculations is shown in tabular form in Table Amendment 18 WI I

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t' For defense-in-depth protection against inventory decreasing events I

where a high drywell pressure is not present, the ADS actuation logic also includes an 8 minute high drywell bypass timer. This timer is initiated upon i

receipt of a LWL 1 signal and is automatically reset if the reactor water level is restored above the LWL 1. After this timer runs out, the need for a high drywell pressure signal to initiate the ADS 29 second delay timer is bypassed (i.e. the 7

29 second delay timer would require only a LWL1 signal to initiate).

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