Safety Injection System Flashcards
What is the purpose of the Safety Injection System?
- Inject borated water into PCS to keep the core covered.
- Inject borated water into Primary Coolant System to raise shutdown margin.
- Remove core heat for extended period of time by keeping core covered via Recirculation and Once-Through-Cooling out the break.
- Provide flushing flow via simultaneous Hot/Cold Leg injection.
- Remove heat from PCS during normal Shutdown Cooling operations.
- Transfer refueling water
What is the operational design of SIS?
Originally designed to prevent fuel and cladding damage that could interfere with adequate emergency core cooling, and to limit the cladding-water reaction to less than 1% following DBA LOCA.
Also functions to provide rapid injection of large quantities of borated water for added shutdown capability during rapid cooldown of the primary system from a main steam line break.
When is the design basis of the SIS met?
Design bases met:
3 of 4 SITs
1-HPSI Pump
1-LPSI Pump
1 D/G
and 25% spillage of SI flow assumed to go out the break to the Containment.
What are minimum tank levels assosicated with SIRW?
DWO-1 in MODE 1, 2, or 3 requires;
- T-58 volume greater than or equal to 275,970 gallons (92%).
LCO 3.5.4 in Modes 1,2 and 3 requires;
- 250,000 gallons is based on two factors:
- At least 20 minutes of full flow from one train of ESF pumps prior to reaching a low level switch over to the containment sump
- The containment sump water volume must be sufficient to support continued ESF pump operation after the switch over to recirculation occurs.
Twenty minutes is the point at which approximately 75% of the design flow of one HPSI pump is capable of meeting or exceeding the decay heat boil off rate
Minimum in MODE 4 is 200,000 gallons (67%)
What is the SIRW boron concentration limit?
LCO 3.5.4
- Max - 2500 ppm
- Min - 1720 ppm
Maximum is based on time before the requirement to establish simultaneous hot and cold leg injection due to boron precipitation in the upper core region.
Minimum is based on the reactor remaining subcritical in the cold condition following mixing of the SIRWT, Safety Injection Tanks, and PCS water volumes
What are the SIRW temperature limits?
Maximum - 100°F
Minimum - 40°F
Preferred band is 85-90°F.
Maximum is based on exceeding 100°F resulting in higher containment pressure due to reduced containment spray cooling capacity.
Minimum temperature limit of 40ºF was selected to maintain a small margin above freezing.
What are the SIRWT outlet valves?
CV-3031, CV-3057 (SIRWT Outlet Valves)
Functions
- CV-3031 supplies west engineered safeguards
- CV-3057 supplies east engineered safeguards
Motive Forece
- High Pressure air with Instrument Air backup. Fail As Is
Controls
- C-03 - Keylock Handswitch (HS)
- C-33 - Handswitch
- OPEN & CLOSED indication on both C-03 and C‑33.
- Normal position is Electrically Locked OPEN (ELO)
What are the SIRWT recirculation valves?
CV-3027, CV-3056
Function
- HPSI and LPSI recirculation lines. Pumps are at shutoff head on SIS until PCS pressure falls below pump discharge pressure.
Motive Force
- HP Air with backup from N2 station 3A
- N2 supplies 24 hours of operation
- Valves fail as is
Controls
- C-03: Hand switch (A) AND keylock switch (B).
- Normal position for HS-A is OPEN / HS - B is ELO
- RAS signal and the 3027A HS in the closed position will close valve.
- 3027A HS in close and “B” keyswitch in close will close the valve.
What are the containment sump outlet valves?
CV-3030, CV-3029 (Containment Sump Outlet Valves)
- CV-3030 supplies west engineering safeguards
- CV-3029 supplies east engineering safeguards
Motive Force
- HP Air with Instrument Air backup. Fail as is on loss of air.
Controls
- C-03 - keylock HS
- C-33 - handswitch
- OPEN & CLOSED indication on both C-03 and C-33.
- Normal position is Electrically Locked CLOSED (ELC)
Sump outlet valves begin openning before SIRWT outlet valves close during RAS.
What are the HPSI pumps?
Seven stage horizontal centrifugal pump.
Minimum flow 25 gpm
Design Flow: 300 gpm at 1,084 psia
P-66A - D Bus
P-66B - C Bus
What are the HPSI subcooling valves?
On RAS, Containment Spray Pumps ARE the suction source for HPSI
CV-3070, P-66B Subcooling
CV-3071, P-66A Subcooling
Motive Force
- Instrument Air with N2 backup from station 3B.
- N2 provides 120 hours of operation
- Fails closed on loss of air
Controls
- C-03 - Key Switch
- C-33 - Handswitch
- OPEN & CLOSED indication on both C-03 and C-33
- RAS - automatic
- CV-3070, P-66B Subcooling opens on P-66B running and CV-3030 open
- CV-3071, P-66A Subcooling opens on P-66A running and RAS signal
Restrictions on Spray Pumps due to Suction Head concerns when providing subcooling - runout conditions possible.
What are the HPSI train supply valves?
CV-3059, HPSI P-66B to TRN 1
CV-3036, P-66A to TRN 2
Motive Forece
- HP Air. Fail open on loss of air.
Controls
- C-03 - Key Switch
- C-33 - Handswitch
- OPEN & CLOSED indication on both C-03 and C-33.
- Electrically Locked OPEN (ELO)
What are the HPSI cross tie valves?
CV-3018, P-66B to Train 1 Cross-Tie
CV-3037, P-66A to Train 2 Cross-tie
Motive Force
- HP air (CV-3018 has SCBA bottle backup - 72hour operation)
- Fail Closed on loss of air
Controls
- C-03 - Key Switch
- C-33 - Handswitch
- OPEN & CLOSED indication on both C-03 and C-33.
- Electrically Locked CLOSED (ELC)
What are HPSI HL and CL injection valves, including the function of hot leg injection?
MO-3080, HPSI Train 2 Cold Leg Injection - MCC-24
MO-3081, HPSI Train 1 Cold Leg Injection - MCC-21
MO-3082, HPSI Train 1 Hot Leg Injection - MCC-22
MO-3083, HPSI Train 2 Hot Leg Injection - MCC-23
- Cold Leg Injection flow is split between a restricting orifice and an injection vavle (50% to each). In order to open a Hot Leg Injection valve, the cold leg injection vavle must first be closed. Prevent runout on HPSI pump.
- With HLI, flow is split between orifice to cold leg and valve to hot leg.
- Keyswitches/HS at C-03, HS at C-33. Light Indication at both.
What are the HPSI Train 1 (Left) Injection Valves?
HPSI Train 1 (P-66B) Loop Injection Valves
- MO-3007, MO-3009 to Loop 1A and 1B Respectively
- MO-3011, MO-3013: to Loop 2A and 2B Respectively
C-03 or C-33 Controls
- Can be throttled
- MO-3007 - MCC-1
- MO-3009 - MCC-1
- MO-3011 - MCC-1
- MO-3013 - MCC-1
What are the HPSI Train 2 Injection Valves?
HPSI Train 2 (P-66A) Loop Injection Valves
- MO-3068, MO-3066: to Loop 1A and 1B Respectively
- MO-3064, MO-3062 to Loop 2A and 2B Respectively
C-03 or C-33 Controls
Can be throttled
- MO-3007 - MCC-2
- MO-3009 - MCC-2
- MO-3011 - MCC-2
- MO-3013 - MCC-2
Describe the LPSI Pumps?
Single Stage Horizonal Centrifugal Pumps
P-67A - D-Bus
P-67B - C-Bus
- Minimum Flow 170 gpm
- Maximum Flow 3000 gpm at 152 psia
What are the LPSI suction valves?
MO-3189, MO-3190: LPSI suction for SIRWT or CNTMT Sump
MO-3198, MO-3199: LPSI suction from SDC
C-03 Controls
- MO-3189, MO-3190: LPSI suction for SIRWT or CNTMT Sump ELO
- MO-3198, MO-3199: LPSI suction from SDC ELC
What is the SDC bypass valve?
CV-3006, SDC HX Bypass Valve
Motive Force
- Instrument Air and fails open on loss of air
Controls
- Keylock HS-0306A on C-02
- Normally in “OPEN” Provides Full LPSI flow to Injection
- Must be in “AUTO” to use FIC-0306
- keylock HS-0306B on C-33
- KS in “ON”, HIC in “AUTO”, this allows control of CV-3006 from the Control Room
SV powered by Y-01
Loss of Y-01 results in valve going open
What are the LPSI injection valves?
- MO-3008 - MCC1; Loop 1A injection
- MO-3010 - MCC-1; Loop 1B injection
- MO-3012 - MCC-2; Loop 2A injection
- MO-3014 - MCC-2; Loop 2B injection
CS on C-03 or C-33
