RHR Purpose:

Remove decay heat from the core and RCS during plant cool down and RFO. Transfer refueling water between RWST and Refuel Cavity.

ECCS:

RWST- Cold Leg Injection

Containment Sump- Cold Leg Recirc

Containment Sump- SI and CH Pp Suction

Containment Sump- Containment Spray Headers

Remove residual and sensible heat for plant cooldown; usually placed in service within 4 hours of Shut down when RCS pressure is < 375 psig and temp < 350F (mode 4); 350F to 140F in 22 hours (with only one loop in service the time will double.)

Piping and Valve Design Basis:

Suction Piping 450 psig/400F

Discharge Piping 600 psig/400F

Pp Seals 350 F

RCS Isolation Valves 2485 psig/650F

ECCS:

Normally aligned to RWST and disch. to all 4 Cold Legs, RH 19s must be open to meet this phase (Injection Phase)

Takes a suction on the containment sump when RWST is depleted and Containment Sump has adequate inventory to support Pp operation during Recirc Phase.

Discharge to cold legs

Can Discharge to Hot Legs

Supplies SI and Ch Pp suction

Supplies 1 CS Header

RHR Shut off head is 170 psig

RHR is required to achieve safe Shut down. System is used for cold Shut down outside MCR.

Location- 45 Aux Bldg

Design:

Pressure 600 psig, Temperature 350F, Flow Normal 3000 gpm @ 151 psid, Flow Accident 4500 gpm @ 130 psid

Mechanical Seal Cooled by CCW

Power Supplied 21- 2A 4KV Vital Bus, 22- 2B 4 KV Vital Bus 

Pp start:

MCR Bezel CC1

Auto Start SEC SI Modes (I, III, IV).

THERE ARE NO MODE 2 STARTS

Pp Trips:

Bus Overload (motor overcurrent)

Bus Diff (SEC Modes 2.3.4 have load strip)

Room Cooler Supplied by SW.

ECCS Pp suction source- Injection

Make Up for Filling Refueling Cavity- Mode 6

Suction Source for CS

400,000 gallon capacity, vented to Aux Building

Make up via CVCS

TS-3.5.5 limits

Min Level- 364,500 gallons

Boron Concentration- 2300-2500 ppm

Temperature 35 F

RWST Heating Loop- Auto start/stop to maintain RWST between 40-45F, Heat trace maintain >50F, Alarm if temp is <40F, temp controller recieves input from AFWST.

Purification-

Refueling water purification Pp

SFP cooling demineralizer and filter

Flow path can also purify cavity or transfer water from cavity to RWST

Single Loop shell and U tube HX, designed to handle 1/2 the DBA load.

Shell (CCW) @ 150 psig and 200F

Tubes (RHR/RCS) @ 600 psig and 400F

Normally open

55 Aux Bldg

87 Stroke Time 

Power- 21RH4- A 230V AC VB; 22RH4- 2B 230V AC VB

Interlocks:

Manual Operation of Associated Containment Sump Vlv (SJ44) must be fully closed to open RH4 (so you don't Pp RWST/RCS to the Containment Sump)

Unit 2 has "Semi-Auto Swap Over" allows SJ44 to open and RH4 auto close.

permissives:

• must ensure adequate Containment Sump Level
• Need 2/4 lvl transmitters in RWST to read Lo-Lo Alarm
• need SI signal from SEC/SSPS
• transfer is "fast acting valves", both valves are only open for a short time
• interlocks in place to prevent loss of suction to RHR Pps

MOVs- SJ44 Containment Sump Isolation Valves

Specs and Interlocks

Normally Closed

45 Aux Bldg

35 sec stroke time

Power 21SJ44- A 230V VB, 22SJ44 B 230 V VB

Interlocks:

Mannually Open- associated RH4 must be fully closed prevents mannually draining RWST to Containment

Semi-Auto Swap- SI and 2/4 RWST Lo-Lo Level Alarm, auto opens if armed, associated RH4 closes when SJ44 is full open

Spurious opening at Power is prevented by lock out on RP 4 and by "not arming the valves"

Normally Open

55 Aux Bldg

25 sec stroke time

Power C 230V VB

Interlocks:

Power Lock out switch on RP 4

This valve could inop RHR because its a single valve feeding both trains of RHR from the RWST 

45 Aux Bldg

30 sec Stroke time

Power 21RH29-A 230V VB; 22RH29- B 230V VB

Auto Operation:

Open <500 gpm with Pp breaker Closed

Closes > 1150 gpm with Pp Breaker Open

Valves must be in auto for RHR to be operable, must work as designed

Valves don't Cycle due to 600 gpm Deadband

If flow is < 500 gpm vlv will be open and stay open until it reaches > 1150 gpm.

Interlocks- NONE

 When RHR is in recirc there is no cooling to the Pp, therefore the Pps can heat up after a short period of time.

Closed.

Valve closes >1150gpm, with Pp breaker open

Normal Open

45 Aux Bldg

10 Sec Stroke Time

Both valves must remain open to meet TS 3.5.2 for injection, ensures that either Pp can inject into all 4 loops/cold legs

Valves must be closed in Recirc Phase, to separate trains and supply different loads (SI Pp, CH Pps, CS Pp)

Power supply 21RH19, A 230V VB, 22RH19 B 230V VB

Interlocks: None

Normally Closed

84 Aux Bldg

10 sec stroke time

Manually opened when in recirc phase

Power Supply 21SJ44 A 230V VB

Interlocks:

• 21SJ44 must be full open to align to containment recirc
• RH1 or RH2 must be fully closed, so you don't align to normal SD cooling path
• 2SJ67 or 2SJ68 SI Pp Recirc to RWST must be fully closed. So you don't align the containment sump to the RWST

Normally Closed

84 Aux Bldg

10 sec stroke time

Power Supply 22SJ44 B 230V VB

Interlocks:

• 22SJ44 must be full open to align to containment recirc
• RH1 or RH2 must be fully closed, so you don't align to normal SD cooling path
• 2SJ67 or 2SJ68 SI Pp Recirc to RWST must be fully closed. So you don't align the containment sump to the RWST

normally closed, 10 sec stroke time

84 aux, Power 21SJ113 A 230V VB, 22SJ113 B 230V VB

Interlocks: None

Only need one valve to open, as they run parallel

Normally open, 78 mech pen, 10 sec stroke time

21SJ49 supplies 21 and 23 Cold Legs

22SJ40 Supplies 22 and 24 Cold Legs

Power supply 21SJ49 A 230V VB, 22SJ49 B 230V VB

Interlocks:

Power Lock out switches in RP4, prevents inadvertent closure, must be used to close valves.

Normally Closed

78 Containment

Not normal flow path for EOPs, used in AB LOCA if hot leg injection is required and SI Pp is not available.

Power is C 230V VB

Interlocks:

Power Lock out switch on RP4, prevent inadvertent opening , also has a key interlock prior to opening the valve

Normally Closed

78 Inner Pen

10 sec stroke time

used to supply CS to header when RWST is empty, and on Recirc

Power Supply 21CS36 A 230V VB, 22CS36 B 230V VB

Interlocks:

Associated with SJ44 must be open

RH1/2 must be closed

2500 gpm for full CS flow

Normally open, failed open, no CA to valve

Failure Modes

FAI, loss of air, FO on loss of control power

controls through respective HX

used in conjunction with RH20 HX bypass to control cooldown rate while maintaining RHR flow within operating band

While at power, if you restore CA to this valve you inop RHR.