ML20136F646

Forwards Info Addressing Remaining Concerns Re Outstanding Issue 11 Concerning Instrumentation & Control for Safe Shutdown.Resolution of Issue Should Be Reflected in Next Sser

ML20136F646
Person / Time
Site:	Perry, Seabrook
Issue date:	12/31/1985
From:	Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:	Noonan V Office of Nuclear Reactor Regulation
References
SBN-917, NUDOCS 8601070452
Download: ML20136F646 (13)

Text

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SEABROOK STATION Engineering Office Pub 5c Service of New Hampshko Mew Hampshire Yonkee Division December 31, 1985 SBN-917 T.F.

B7.1.2 United States Nuclear Regulatory Commission Washington, DC 20555 Attention:

Mr. Vincent S. Noonan, Project Director PWR Project Directorate No. 5

References:

(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444

Subject:

Instrumentation and Control for Safe Shutdown (SER Outstanding Issue No. 11)

Dear Sir:

Provided herewith are Attachments 1 and 2 which address the remaining concerns identified by the staff in regards to the above referenced SER outstanding issue. These concerns were identified during our November 1985 meeting with the staff (ICSB) as clarified by our telecon of December 30, 1985.

We believe that the enclosed completes our response to the above referenced SER outstanding issue. Accordingly, we request that the resolution of this issue be reflected in the next supplement to Seabrook Station's SER.

Very truly yours, j

John DeVincentis, Director Engineering and Licensing

. Attachments cc: Atomic Safety and Licensing Board Service List Oh1070452851231 h

ADOCK 05000443

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PDR AD - J. Knight (Itc only)

EB (BALLAHD)

'.EICSB (ROSA)

PSS (GAMMILL)

P.O. Box 300 + Seobrook. NH O3874. Telephone (603) 474-9521

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SBN-917 (TTACHMENT 1 Response to Remaining Concerns Item 1 Explain your position on disabling the automatic actuation of engineered safety features. Address why, how, what is disabled, and actions required to restore automatic actuation.

Reuponse Discussion of the disabling of automatic actuation of engineered safety features is provided in the attached markup of FSAR Section 7.4.5.2 (Attachment 2).

Itti 2 What is the effect of nonseismic service water pipe failures that are not large enough to cause automatic cooling tower actuation?

Response

The adequacy of reduced service water flew without cooling tower actuation is provided in the attached markup of FSAR Section 7.4.5.5 (Attachment 2).

Item 3 Verify that all RSS instrumentation is seismically quallfled.

Response

The RSS instrumentation will be seismically qualified as discussed in FSAR Section 7.4.6.

Item 4 Address testing of RSS controls.

Response

Testing of RSS controls is discussed in the attached markup of FSAR Section 7.4.6 (Attachment 2).

Item 5 Address the evaluation deleted from FSAR Section 7.4.6 in Amendment 56.

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SBN-917 ATTACHMENT 1 Response to Remaining Concerns (Continued)

Response

This evaluation is contained in the attached markup of FSAR Section 7.4.6 (Attachment 2).

Item 6 Address the backup air su; ply for the ASDVs.

Response

The backup air supplies for the ASDVs are discussed in the attached markup of FSAR Section 7.4.6 (Attachment 2).

Item 7 Discuss controls for Tower Actuation at RSS locations.

Response

Discussion of the automatic actuation of the cooling tower and associated RSS controls is provided in the attached markup of FSAR Section 7.4.5.5 (Attachment 2).

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SBN-917 ATTACHMENT 2 Revised FSAR Section 7.4 Excerpts Seabrook Station f

SB 1 & 2 Amentimen t 56 FSAR November 1985 tg dlOb by U u W.w y

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nK the' RSS locations the operators will transfer control of safe shutdown A

at equipment to the RSS locations by means of key-locked REMOTE-LOCAL selector switches. Access to the keys required for operation of the RSS location controls is administrative 1y controlled and will be available when the main l

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control room is evacuated.

Initially, control and monitoring of iital plant parameters for the functions listed in Subsection 7.4.5 will be performed by the minimum on-site operating crev. Hence, indications and controls for all pumps, fans, and critical valves, which may be operated initially by a limited number of operators, have been consolidated into a minimal number of locations.

Equipment that was operating prior to transfer to the RSS locations will continue to operate during and after the transfer.

7.4.5 Systems and Equipment to Support Safe Shutdown Functions Redundant safety-grade equipment is available to support safe shutdown functions. Control and monitoring capability is provided both in the main control room and RSC locations, unless stated otherwise. Further details for each of the scfe shutdown functions is provided below.

7.4.5.1 Decay Heat Removal

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Decay heat transfer is made possible by natural circulation in the RCS.

It will be monitored by T ot, Tcold, and RCS pressure indication.

h RCS temperature is controlled by the steam generator atmospheric relief valves (ARVs). Steam generator water inventory is controlled by operating the emergency feed pump (s) and associated emergency feedwater flow control valves for each steam generator.

Long-term plant cooldown is provided by the RHR System which transfers decay heat from the RCS to the primary component cooling water (PCCW) system.

7.4.5.2 Reactor Coolant Inventory and Pressure Control Operation of portions of the chemical and volume control system (CVCS) to for RCS leakage and cooldown volume shrink is accomplished using compensate a centrifugal charging pump and a borated water supply. The charging flow path will be established through the cold leg injection lines by opening the charging flow isolation valves. RCS inventory will be monitored through 61 %

pressurizer level. The source of borated water for the charging flow will be from the boric acid tanks (BAT) and/or the refueling water storage tank (RWST) with the volume control tank (VCT) isolated. The pressurizer power-operated relief valves (PORVs) and pressurizer heaters, if available, are

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used for RCS pressure control.

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Following the initiation of plant cooldown and depressurization from the RSS locations for a remote shutdown without a fire, the solid-state protection c

7.4-3

SB 1 & 2 Amendment 56 FSAR November 1985

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52 7.4.5.3 Negative Reactivity Addition Control Operation of the boration portion of the CVCS to assure sufficient shutdown margin for a plant cooldown is accomplished by operating a single centrifugal charging pt.mp taking suction from one of the boric acid tanks and the refueling water storage tank.

7.4.5.4 Electrical Power Supply Emergency electric power (EDE System) controls and instruments which are required for RSS are provided at RSS locations. The EDE System, which includes the diesel generators, emergency buses, inverters, batteries, and their associated equipment, is designed to provide electric power to equip-52 ment required for safe shutdown.

The diesel generator units start automatically following a loss of offsite power or on a safety injection (SI) signal. Manual control of diesel startup is provided locally at the diesel generators as well as in the control room. Upon loss of offsite power, selected loads connected to thc.

emergency electric power system are tripped by undervoltage relays. If diesel generator control has been transferred to the RSS locations, the 52 operators will have to manually clese the diesel generator breakers to energize the emergency buses.

7 Those loads that do not have their control transferred to the RSS locations will be automatically sequenced onto the diesel by the EPS. The loads that have been transferred to the RSS locations must be manually loaded on to the l

diesel generator. Manual loading will be coordinated with the operator at l%

52 the diesel generator to prevent overloading.

7.4.5.5 Plant Cooling System Operation of at least one service water /PCCW train is required to maintain

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equipment cooling and for subsequent RHR operation. C: ling ter : ::::: tic:

b 1 12,_ R ti::lly i: initirt:f fr-- ler cervice 2 ter per; diccherg: pre:-

Cooling tower actuation, loss of offsite power, or safety injection,

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isolates the non-seismic SW piping to ensure adequate flow to the safety users.

49 54 7.4-4

SB 1 & 2 Amendment 56 FSAR November 1985 The indication of bypass of systems required for safe shutdown is discussed in Subsection 7.1.2.6.

Instrumentation at the RSS locations is independent of the main control room instrumentation. It is activated continuously so that its availability can be monitored. Provisions have been made for testing instrumentation channels during power operation. The RSS instrumentation will be available following all natural phenomena. 'iL K65 c'e. (w/5 ch /j, Ic-<le./

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Portions of the instrument air system may be used for the RHR air-operated valves necessary for safe shutdown. Normal operation of the RHR System utilizes instrument air for the control of the RHR heat exchanger outlet and bypass valves. Should the instrument air system be unavailable, the RHR l

5L heat exchanger bypass valve will fail to the closed position and the RHR heat exchanger outlet valve will fail to the full-open }.osition. This failure mode provides full RHR flow through the RHR heat exchanger.

Analysis of system startup and operation under these conditions has shown that an acceptable cooldown rate of less than 500F/hr will result.

Therefore, plant operation at hot standby and cooldown to cold shutdown can be accomplished without the use of the instrument air system.

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The station service water system is explained in Subsection 9.2.1.

The safety evaluation is presented in Subsection 9.2.1.3.

The primary component cooling water system is explained in Subsection 9.2.2 and the safety p sE d evaluation is presented in Subsection 9.2.2.3, in detail.

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The results of the analysis which determined the applicability of the NRC General Design Criteria, IEEE Standard 279-1971, applicable NRC Regulatory Guides, and other industry standards, to the equipment required for safe shutdown, are presented in Table 7.1-1.

7.4.7 Equipment Required for Safe Shutdown The equipment required to accomplish safe shutdown functions is listed in Tabic 7.4-1.

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TABLE 7.4-1 (Sheet 6 of 9)

Instrumentation RSS Control Location Description

. Device Location MCB CP108A CP108B Local

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Cooling Tower Pump..

SW-P-110A Bus E5 Cooling Tower Pump '

SW-P-110B Bus E6 CT Pump Disch Valve

- SW-V54 CP-108A

. CT Pump Disch Valve SW-V55 CP-108B CT FAN SW-FN-51A Bus E5

. CT FAN-SW-FN-51B CP-108B

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. CT Spray Bypass Recire-

.. Valve SW-V139 Local

' CT. Spray Bypass Recire Valve:

SW-V140 Local Y

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o SB 1 & 2 Amendment 56 FSAR November 1985 TABLE 7.4-1 (Sheet of )

Instrumentation RSS Control Location Description Device Location MCB CP108A CP108B Local RHR Ex Valve RH-HCV-607 Distr. Panel PP-112B RHR Suction From RNST CBS-V-2 Local (Loop A)

RHR Suction From RWST CBS-V-5 Local (Loop B)

8) Sampling:

RCS Saopling (Loop #1)

RC-FV-2832 CP-108A RC-FV-2894 CP-108A RCS Sampling (L9op #3)

RC-FV-2833 CP-108B RC-FV-2896 CP-108B l

RHR Local Sample RH-V-8 Local 56 Valves RH-V-44 Local

9) Solid State Protection System (SSPS):

SSPS Output Train A KH-CP-12 Distr. Panel PP-1A SSPS Output Train B MM-CP-12 Distr. Panel PP-1B

10) Electrical Power Supply:

Diesel Generator A DG-1A Local Diesel Generator-B DG-1B Local D

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'.J Insert A Intake tennel failure'that results in the complete loss of the seawater supply to

~ the service water pumps or failure of nonseismic service water piping large enough o

-to prevent adequate cooling of safety systems will result in automatic actuation oftbecoolingtoweronlowservicewaterpumpdischargepressure. If the cooling towers are actuated there are manual actions required at the tower to detect a loss of inventory due to pipe or valve failure and to manually-close the spray header bypass valve to_ start flow into the spray header after the basin is heated sufficiently

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to prevent icing.

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Insert B Safety grade backup air supplies have been provided to components which must remain operable for safe shutdown. Refer to FSAR Section 9.3 for further discussion.

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' Insert C The.rel'ect;on of instrumentation and controls for safe shutdown has ine'uar-1 consideration _of the event consequences that minht jeopardize safe shutdown conditions. The event consequences:that are germane are those that would tend to degrade the capabilities

, for boration, adequate supply for emergency feedwater, and residual. heat reano rai.

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Insert D system output cabinets are de-energized to prevent ESF actuation, mainly Safety

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Injection. This removes. automatic actuation signals from ESF equipment.

If

' ESF equipment is needed later during the plant cooldown, the SSPS output

' cabinets can be re-energized at any time to provide the_ automatic actuation 4

signals to the ESF equipment that was not transferred tx) local conirol.

During the cooldown process, the safety injection accumulators are isolated or their cover gas vented. The safety injection pumps and one charging pump are disab1'ed as part of the standard operating procedure for any shutdown to avoid low temperature over-pressurization (LIOP) of the reactor vessel.'

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