ML19241A689

Alternative Shutdown Capability Conceptual Design Description

ML19241A689
Person / Time
Site:	Fort Calhoun
Issue date:	06/07/1979
From:	OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML19241A686	List: ML19241A685 ML19241A689
References
ZAR-790607, NUDOCS 7907090293
Download: ML19241A689 (9)

Text

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cst.g.2-2 FORM Al ternate Shutdown Capabili ty PREPARED BY M Conceptual Design Descri,ntion CHECKED BY h v ', 1 g g. CONT. CN SH.

APPROVED - 6//

REV. / DATE 4 7 7,7 OMAHA PUBLIC POWER DISTRICT MR NO. r C-78 GENER ATING STA. ENG.

FORT CALHOUN UNIT #1 ALTERNATE SHUTDOWN CAPABILITY CONCEPTUAL DESIGN DESCRIPTION MR FC-78-56 TABLE OF CONTENTS

1. 0 DESIGN REQUIREMENTS 2.0 TECHNICAL DESCRIPTION

3. 0 ANALYSIS 3.1 Primary System Inventory Control 3.1.1 Chemical and Volume Control System (CVCS) 3.1.2 Charging Pump CH-1B 3.1. 3 Letdown Control Val ~e (TCV-202) 3.1.4 Volume Control Tank Level Indication 3.1.5 Pressurizer Pressure and Level Indication 3.1. 6 Pressurizer Power-Operated Relief Valves (PORV) 3.1.7 Pressurizer Backup Weaters 3.1.8 Pressurizer Spray Valves

3. 2 Decay Heat Removal 3.2.1 Auxiliary ~aedwater System (AFS) 3.2.2 Steam Generator Pressure ano Level Indicator 3.2.3 Main Steam Safety Relief Valves

3. 3 Reactivity Ccntrol

3. a Aux i ', i a ri e s 3.4.1 Diesel Generator Number 2 3.4.2 ~ Load Shed 3.4.3 Diese1 Fire Pump 4.0 SEQUENCE OF EVENTS 5.0 CRITICAL QUALITY EQUIPMENT (CQE)

G. 0 DRAWINGS 309 068 7

9 0 7 0 5 0 ^'> o '

REV. 1/79

GSE-8-2-2 FORM Ai Lamate Snutccan Capebili ty PREPANED BY M Conceptual Design Description CHECKED BY <2' gg 2 CONT. CN SH.

APPROVED (M REV. / DATE m in OM AHA PUBLIC POWER DISTRICT MR tio. FC-78-Se- GENER ATING STA. ENG.

FORT CALHOUN UNIT #1 ALTERiiATE SHUTDOWN CAPABILITY C0rtCEPTUAL DESIGN MR-FC-78-56 1.0 DESIGN REQUIREMENTS This design package is in response to our connitment to NRC for pro-viding altemate shutdown capability, independent of cabling in the Cable Spreading Room or the Control Room for Fort Calhoun Unit il (Reference SER Section 3.1.21).

The assumptions made in preparat1on of this conceptual design are as follows:

The Control Room is lost because of fire in the Control Room or the Cable Spreading Room.

Off-site power is lost.

Other than the fire in the Con'rol Room or the Cable Spreading Room, there is no accident condition.

The plant is required co be placed and maintained in a hot shutdown condition with a minimum crew of one operator at the altemate shutdown panel and a helper in the plant. When the fire is under control, sufficient additional personnel are available, and off-site power has been restored, the plant will be taken to cold shutdown using new emergency procedures.

2.0 TECHNICAL DESCRIPTION The following modifications are proposed:

a) An alternate shutdown panel (ASP) will be added and installed next to the auxiliary feedwater panel AI-179 in the electrical pene-tration room at Elevation 1013'-0".

The following instruments and controls shall be provided on this panel:

- Primary Loop Hot Leg Temperature Indicator

- Primary Loop Cold Leg Temperature Indicator

- Volume Control Tank Level Indicator 309 069 REV. 1/79

GSE-B-2-2 FORM -

A #'# ~" ~"" * "9I !E7 PREPARED BY

• Conceptual Design Description CHECKED BY * ' ' " 3 gg. CONT. ON SH.

APPROVED M REV- ' DATE c,.9-ye OMAHA PUBLIC POWER DISTRICT MR NO. FC- 2-Do GENER ATING STA. ENG.

- Pressurizer Level Indicator '

- Transfer Switch " Remote-Local close" with one set of indicating lights for: TCV-202, PCV-103-1, PCV-103-2  ;

- Transfer switch " Remote-Local open" with one set of indicating  !

lights for HCV 239

- Open/Close indication for: HCV-150, HCV-151, HCV-240, and PCV-102-2

- Transfer Switch " Remote-Local Start-Local Stop" Wi th One Set Of indicating lights for C.i-1B b) The controls for steam driven auxiliary feedwater pump, valves and the following instruments are already provided on Panel AI-179:

Steam Generator RC 2A Level Indicator Steam Generator RC 2A Pressure Indicator Steam Generator RC 2B Level Indicator Steam Generator RC 2S Pressure Indicator Pressurizer Pressure Indicator PI-115A1 and Pressurizer Pressure Indicator PI-115A2 c) The following plant functions and systems will be made avai'able for operation from the alternate shutdown panel , AI-179 and other remote stations located in the Diesel Room, the Switchgear Room and the Electrical Penetration Room. The equipment necessary for operating of these systems has been highlighted on the drawing.s listed in Section 6. -

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a) Primary System Inventory Control (See E-23866-210-110

& 120'Sh. 1)

Chemical and Volume Control System Pressurizer Pressure and Level Indication Pressurizer Power Operated Relief Valves (PORV)

Backup Pressurizer Heaters b) Decay Heat Removal (See Drawing #11405-M-252 & 253)

Auxiliary Feed,ater System Steam Generator Pressure anc Level Indication Main Steam Safety Relief Valves Reactor Coolant Temperature (See E-23866-210-110) c) Reactivity Control (Refer to Section 3. 3. )

iv) Auxiliaries Diesel Generator #2 Diesel Driven Fire Pump 0 O 309 REV. 1/79

GSC-B-2-2 FORM Altemete Shutdown Capability PREPARED BY nc.- Cc ceptual Design Description CHECxED BY A^ '>

g g.

4 CONT. ON SH.

APPROVED &

REV' / DATE 6 "'?"

MR NO. FC-78-56 GENER ATING STA. ENG.

Provisions shall be made for i olating electrical equipment necessary for operation of systems listed above from Control Room. Key locked local controls shall be installed for operation of necessary equipment from remote locations. All electrical modifications shall be designed according to IEEE-279-1971.

3.0 ANALYSIS This section provides an analysis of various plant systems required to bring and maintain the plant to hot shutdown condition and outlines the equipment and modifications necessary for performing the intended functions.

3.1 Primary System Inventory Con trol Systems and instruments required for primary system inventory control I are discussed below.

3.1.1 Chemical and Volume Control System (CVCS)

The CVCS is required in the event of this emergency to provide make-up water for the primary system for maintenance' of the pressurizer level above the lower limit. Following a reactor trip, the primary coola'nt temperature will be reduced to the no-load temperature condition as dictated by the steam generator temperature condition, and will then gradually increase until the auxiliary feedwater system is placed in service to maintain the primary system temperature and pressure.

The operator will then control the pressurizer level by operation of charging pump CH-18. Feed tc this charging pump shall be from the volume control tank.

3.1.2 Charging Pumo CH-1B ine charging system was cnosen over the high pressure safety injection -

(HPSI) system for maintaining the primary inventory because the maximum head of the HPSI pumps is 1,735 psig versus a primary system pressure of 2,100 psig at hot shutdown. Charging pump CH-1B was chosen because it is powered by train 4 (bus 1A4, ' diesel generator number 2).

Diesel 02 will be run locally; the power supply will be unaffected by a loss of the Control Room or Spreading Rocm.

309 071 REV. 1/79

"i te rn a te ..iu t;;wn u.p c . . g G SE- 8-2-2 TORM Iv(. Conceptual Desien Description PREPARED BY CHECKED BY_ * *' gg. 5 CONT. ON SH. b APPROVED W R E V- / DATE l'- @ M MR no. FC-78-56 GENER ATING STA. ENG.

Controls for the operation of Charging Pump CH-1B will be added to the alternate shutdown panel.

To operate the pump using the local control switch, the external wires, (CH-18-PC, CH-1B-T, CH-1B-NT , CH-18-GW and CH-1B-PT at breaker 184C-6) will be locally isolated at the switchgear. This will prevent spurious signals from the Control Room from starting the pump, tripping the pump or blowing the fuses.

The remaining two charging pumps, CH-1A and CH-1C, will be protected from inadsertent operation by tripping and "lockingout" the breakers in the Switchgear Room.

The following valves must be in the "open" position for the pump tc take suction from the volume control tank and discharge into the 2A primary loop. It is not necessary to operate or modulate these valves, as the flow variations will be accomplished by operating the pump.

LCV-218-2: This motor operated valve is on the pump suction line, its normal operating position is open, and it fails "AS-IS". As a backup, the valve can be manually opened. To avoid spurious closing, breaker located at MCC 3A2 can be locked open.

HCV-239: This is a control valve on the discharge side of the charging pump inside the containment which fails in the safe open posi ti on.

(If additional b$ ration is required or the volume control tank does not contain sufficient water, the charging pump suction can be aligned to the Safety Injection & Refueling Water Tank ($1 RWT) by manually closing valve LCV-218-2 and opening valve LCV-218-3).

HCV 240: To avoid the possibility of inadvertent auxiliary spray, HCV 240 should be closed. This is a pneumatic valve and fails closed.

"Open-close" indication for tnis valve will be provided on ASP.

3.1. 3 Letdown Control Valve (TCV-202)

TCV-202 is an electro-pneumatic control valve required for the primary loop letdown system. It receives its electrical signal from the main control boards CB-1, 2, 3. Electrical supply is from D.C. bus number 1 via distribution panel AI 41A. During this emergency, this valve should be in a closed position.

The loss of electrical signal or air results in this valve failing closed. The control / indication cable between the electrical penetration and main control board will be rerouted through the local-Remote-Close transfer switch in the alternate shutdown panel. Lights will also be provided on the new shutdown panel to provide open/close indication.

309 072 REV. 1/79  ;

FORM Alternate Shutdown Capability GSE-B-2-2 PREPARED BY I k< conceptual Design Description CHECKED BY QC Sg, 7 CCNT. ON SH.

b APPROVED U/

REV' 2- DATE (/u/77 OMAHA PUBLIC POWER DISTRICT MR NO. FC 78-56 / GENER ATING STA ENG.

3.2 Decay Haat Removal .

Systems, equipment and instruments required for decay heat removal are outlined below. -

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3.2.1' Auxiliary Feedwater System (AFS)

This system will be used to mmove the decay heat from the core via the primary system and the steam generators. Following a reactor trip _. _

there is sufficient water in the steam generators to provide heat removal from the primary system for a period of 12 minutes. There is ,

therefore, sufficient time before any operator action on the AFS is req ui red. A steam driven auxiliary feedwater pump (FW-10) is proposed to be used for pumping feedwater.

The AFS turbine is supplied with steam from the main steam system via valves YCV-1045 A and B, and YCV-1045, see 11405-M-252. The controls for these valves are already on panel AI-179.

Valves HCV-1107A and B and HCV-1108A and B should be open to supply feedwater to the steam generators, see 11405-M-253. Valves 1107A and 1108A are located within the containment, while 1107B and 11088 are located in the Auxiliary Building. The valves are fail-open and can be placed in the desired position by removing power frcm them. ,

The valves are redundantly fed by 125VDC from Control Room panel CB-10 (D.C. Bus 1) and auxiliary feedwater panel AI-179 (D.C. Bus 2).

Upon loss of the Control Room power and control for these valves, control can be transferred from CB-10 to panel AI-179 using the transfer switch presently installed in AI-179. In addition , the transfer switch isolates the control circuits from the Control Room; this prevents spurious signals, therefore, no modification is required for the circuitry of valves HCV-1107A and B, and HCV-1108A and B.

Necessary controls for the coeration of the steam driven feecwater pump are also provided on panel AI-179. .

3.2.2 Steam Generator Pressure and Level _ Indication .

Pressure and level indication for the steam generator are already provided on panel AI-179.

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3.2.3 Main Steam Safety Relief Valves _ __

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No modification or operator action is required for these valves to perform the necessary function of relieving steam to the a.tmosphere. -

These valves will relieve at a secondary steam generator pressure of 1,000 psia, following mains meam isolation. They will reseat at a pressure of 950 psia.

309 073 REV. 1/79

GSE-8-2-2 FORM Al ternate Shutacwn Capabili ty

. PREPARED BY M Conceptual Design Description CHECXED BY ##^ '/

gg. 8 CONT. ON SH. 9 APPROVED W FC-78-56 R E V. / D AT E /; n OMAHA PUBLIC POWER DlsTRICT MR NO.

GENER ATING STA. ENG.

3. 3 Reactivity Control ,

The rod control system is of fail-safe design. Faulting in this system circuit trips the reactor. Follcwing a reactor trip, soluble poison may be added to the primary system to further assure subcriti-calily. The chemical and volume control system is normally used for such boron addition; CH-1B will be used for pumping borated water.

3. 4 Auxiliaries Plant auxiliaries required for this emergency are outlined below.

3.4.1 Diesel Generator Number 2 One diesel generator is required to supply auxiliary station power in the event normal power is interrupted during a fire in the Control Room or Cable Spreading Room.

Nomal control and test of the diesel generators is at Control Room panels Al-30A and AI-308. If these panels and/or associated cabling are destroyed, provisions have been made, on the local diesel generator control panels to transfer the circuits to the local panels via a trans fer swi tch (183). Power cables from the diesel generators are routed such that they will not be affected by fire in the Control or Cable Spreading Rooms. The only required modification is a minor' change to the 183 switch so it will also " isolate" the circuits from panel CB-20 located in the Control Room.

3.4.2 Load Shed To avoid overloading of Di_esel Generator #2, load shedding on both a80V and 4160V busses shall be required. Under normal plan t condi tion , ,

load shedding on 480V busses is done from Panel Al-308 and AI-1098.

During this emergency, it is assumed that panel Al-30B may be lost.

Panel Al-1093 is lccated in the Switchgear Room and all load shedding relays are located in :nis panel. These relays can also be actuated from local control station for diesel generator panel AI-1338. Some minor modification will be required to isolate panel AI-1098 from the Control Room and provide it with 'an alternate control power source.

Load shed on 4160V busses is done by under oltage relays located in P:nel CB-20 (Control Room). Loss of this panel is assumed with fire in Control Room and as such provisicn shall be made in emergency pro-cedures to open and lock non essential 4160V breakers. Procedure will also provide for tripping of all loads connected to bus 1A4, before diesel generator #2 is brought on line.

309 074 i

REV. 1/79

ni ternate Shutcown Capabili ty GSE-B-2-2 FORM

. PREPARED BY $t', Conceptual Design Description CHECKED BY e* d s gg, 9 CONT. ON SH.

APPROVED M R E V- I DATE 5-4-O', OM AHA PUBLIC POWER DISTRICT MR NO. FC-78-5o GENER ATING STA. ENG.

3.4.3 Diesel Fire Pump The diesel fire pump can be operated manually from the Screcn House and the Control Room. The controls from the Control Room will be isolated at the Screen House.

4. 0 SEQUENCE OF EVENTS This section outlines the sequence of events and operator actions required following the loss of the Control Room and the Cable Spreading Room. This is not a detailed procedure, which is outside the scope of this design package and will be part of detailed design. The i n ten t here is to demonstrate the feasibility of maintaining a safe hot shut-down condition with the two-man crew.

As soon as Control Room evacuation is ordered, the reactor operator will trip the reactor from the Control Room and then proceed to panel AI-179.

The following is an outline of the actions of the two-man cmw.

TIME PANEL OPERATOR HELPER 0-10 Mins. Proceeds to AI-179. Starts Load sheds Bus'1A4 &.

up auxiliary feedwater system. proceeds to diesel numbe r 2, i solates diesel from Control Room and starts it.

10 Mins. - Monitors plant instrumenta- Proceeds to Charging 1 Hour tion. Determines whether Pump CH-13. Pe rfo rms charging pump ooeration is pump isolation and neces sa ry. val ve alignment.

12 Hours 4 Hours

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_. _ Aligns fire protection System to fill emer-gency feedwater tank.

5.0 CRITICAL QUALITY EQUIPMENT (CQE) 5.1 All cables and alternate shutdown panel are clase,ified as Critical Quali ty Equipment. Components added to existing safety related circuits shall also be COE.

r 309 O,la REV. 1/79

GSE-8-2-2 FORM PREPARED BY /L'S

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E '"" uPU Conceptual Design Description !7 CHECKED BY Gv' g g. 10 F CONT. ON SH.

APPROVED GV REV I DATE 4~.g.co OMAHA PUBLIC POWER DISTRICT MR t40. FC-78-56 GENER ATING STA ENG. _

6.0 DRAWIt4GS Systems necessary for' plant shutdown are shown on the folicwing d rawi n gs. Equipment necessary for operation of these systems has been hi ghl i ghted. -

1. E-23866-210-110

2. E =23866-210- 120 ,

3. 11405-M-252

4. 11405-M-253 e

m 309 076 REV. 1/79

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