ECCS

Question 1

ECCS acceptance criteria:

Answer 1

1. Peak fuel cladding temp <2200F
2. Cladding oxidation <17% of total clad thickness
3. Hydrogen production <1% of reaction of all cladding would generate
4. Coolable core geometry
5. Long term core cooling can be maintained

Question 2

3 reasons for hot leg recirc:

Answer 2

1. Increases core flow (assuming cold leg break)
2. Prevent boron plating out (due to boiling) which:
   a. Blocks flow channels
   b. Reduces heat transfer
3. Suppresses boiling in the core

Question 3

What are the 8 SVAG valves?

Answer 3

1. SI 8806 open RWST common isolation to SI suction
2. SI 8835 open Common SI disch to all 4 cold legs
3. SI 8813 open SI common recirc line to RWST
4. SI 8809A, B open RH discharges to all 4 cold legs
5. SI 8840 closed RH common discharge to A and C hot legs
6. SI 8802A, B closed SI discharges to all 4 hot legs

Question 4

RWST high alarm ____
low alarm_____
Lo-2______
Lo-3______

Answer 4

96%
90%
46.7%
12%

Question 5

Power supply setup of the CV mini flow valves ensures ________ of both pumps mini flows on loss of _______.

Answer 5

Positive isolation
Loss of one ESF bus

Question 6

Injection phase, what happens?What is the flow path?

Answer 6

Flowpath: RWST and Accumulators go to cold legs
1. CV pumps start
2. 112D and E open, 112C and B close
3. SI8801A and B open CV discharge to all 4 cold legs
4. SI pumps start injecting through SI 8821A and B crossconnects and SI 8835 to all 4 cold legs.
5. RHR pumps start and inject through SI 8809A and B to all 4 cold legs.
6. CV8105 and 8106 close, charging header isolations
7. CV8110 and 8111 close w/ RWSTlo-2 mini flows
8. CV8114 and CV8116 cycle 1448-1643#
9. SI accum valves SI8808s get open signal

Question 7

SI accumulator LCO values:
Boron ______
Level______
Pressure_____
8808 valve status______

Answer 7

2200-2400ppm
31-63%
602-647#
De-energized and open

Question 8

CV pumps rated pressure and flow plus random power and amperage rating

Answer 8

2600 psid shutoff
2500 psid @ 150 GPM
600 psid @ 550 GPM

381KW at 57amps

Question 9

SI pumps rated pressure and flow

Answer 9

1500 psid shutoff
1200 psid @400 gpm
800 psid @ 650 gpm

Question 10

RH pump rated pressure and flow

Answer 10

200 psid shutoff
165 psid @3000 gpm
125 psid @ 5000 gpm

Question 11

SI signals:

Answer 11

1. Manual 1/2 switches
2. Low pzr pressure <1829 psig 2/4 blocked P-11
3. Low steamline pressure <640 psig 2/3 on 1/4 SGs rate sens
4. Cnmt Hi-1>3.4 psig 2/3

Question 12

In Mode 4, one 8716 valve must be _____ to prevent lifting the other train ______.
In Modes 1-3 if either 8716 valve is closed, _______.

Answer 12

Closed; relief valve
Water will not flow through cross connects to all 4 cold legs, only 2 cold legs with one pump running

Question 13

Cold leg recirc general steps, flowpath

Answer 13

Flowpath is containment sump to all cold legs.

1. Manually open CC to RHR hxs
2. Cont sump >=8 inches
3. SI8811A/B open, close SI8812A/B
4. Check SI/CV in injection mode
5. All pumps disch to cold legs:
   a. CV8110, 8111, 8114, 8116 closed
   b. SI8813, 8814, 8920 SI recircs closed
   c. RH8716A/B rh crossties manually closed
   d. Open CV8804A and SI8804B
   e. SI8807A/B and SI8924 manually opened
6. Reset SI
7. CV112D, E and SI8806 manually closed
8. RWST <12%:
   -Open CS009A/B Sump suctions
   -Close CS001A/B RWST suctions
9. RWST <9%
   -Stop all pumps taking suction off the RWST

Question 14

Hot leg recirc flowpath and major steps:

Answer 14

Flowpath ‘A’ RHR to A/C hot legs, ‘B’ RHR to SI and CV Pps, SI to hot legs, CV to cold legs. 6 hours after SI.

1. Close 8809A/B SI discharge to all 4 cold legs
2. Open RH8716A RHR crosstie
3. Open SI8840 RHR to A/C hot legs
4. Stop A SI pump, close SI8821A cold legs, open SI8802A hot
5. Restart A SI pump to A and D hot legs
6. Same step for B SI pump
7. Close SI8835 to cold legs (not needed anymore)

Question 15

3.5.2 ECCS operating

Answer 15

3.5 EMERGENCY CORE COOLING SYSTEMS (ECCS)
3.5.2 ECCS-Operating
LCO 3.5.2 Two ECCS trains shall be OPERABLE.
—————————-NOTES—————————
1. In MODE 3, both Safety Injection (SI) pump flow paths
and a portion of both Residual Heat Removal (RHR) pump
flow paths may be isolated by closing the isolation
valves for up to 2 hours to perform pressure isolation
valve testing per SR 3.4.14.1.
2. In MODE 3, a portion of both Residual Heat Removal (RHR)
pump flow paths may be isolated by closing the isolation
valves for up to 2 hours to perform pressure isolation
valve testing per SR 3.4.14.1, provided an alternate
means of cold leg injection is available for each
isolated flow path.
————————————————————
APPLICABILITY: MODES 1, 2, and 3.

Question 16

If one ECCS train inop ______ to restore. If two trains inop, but still capable of 100% injection flow ______ to restore. If two trains inop and not 100% injection flow______.

Answer 16

7 days
72 hours
3.0.3

Question 17

Manual CV valves that send water to all 4 cold legs are throttled to ________.

Answer 17

Limit runout, equalize flow and minimize spilled water to the broken loop.

Question 18

RH8735 may be opened in Mode 4 if __________.

Answer 18

attendant nearby with comms to close valve on ESF actuation.

Question 19

LCO 3.5.3 ECCS shutdown

Answer 19

3.5 EMERGENCY CORE COOLING SYSTEMS (ECCS)
3.5.3 ECCS-Shutdown
LCO 3.5.3 One ECCS train shall be OPERABLE.
APPLICABILITY: MODE 4.
ACTIONS
———————————-NOTE———————————
LCO 3.0.4.b is not applicable to ECCS high head subsystem.
———————————————————————–

Question 20

No risk assessment is allowed to enter Mode 4 without a ____________.

Answer 20

High head CV ECCS system. Can’t use 3.0.4.b

Question 21

4 accident conditions that form the design basis for ECCS:

Answer 21

Pipe breaks/spurious reliefs lifting
CRDM rupture/rod ejection accident
Pipe breaks/spurious reliefs lifting secondary side
SGTR

Question 22

What are the three phases of ECCS injection and why necessary?

Answer 22

a. ECCS injection phase provides borated water to the reactor vessel as RCS pressure decreases during a LOCA in order to limit any fuel damage by keeping core covered.
b. Cold leg recirculation phase of ECCS recirculates borated water from the containment recirc sumps to the cold legs of the RCS to provide long term core cooling.
c. Hot leg recirculation is to provide a means of terminating boiling in the core should the LOCA be due to a break in one of the RCS cold legs, prevent boron precipitation in the top of the core, by maintaining boron concentration 23.53% or less. Maintains long term core cooling.

Question 23

Valves required to be open on SI signal are ______ and valves required to be shut are ______.

Answer 23

Parallel; series

Question 24

What automatic action initiates the switch-over from injection to cold leg recirc?

Answer 24

Lo-2 RWST level initiates the switch over from injection phase to cold leg recirc with a SI signal present.

Question 25

TRM 3.5.a Mode 5 and 6 makeup source

Answer 25

3.5 EMERGENCY CORE COOLING SYSTEM (ECCS)
3.5.a ECCS Subsystems - Tavg ≤ 200°F and Pressurizer Level ≤ 5%
TLCO 3.5.a One of the following means of decay heat removal shall be
available:
1. One Safety Injection (SI) pump and flow path, or
2. A flow path to permit gravity feed from the RWST to the
Reactor Coolant System (RCS) with the reactor vessel
head removed.
APPLICABILITY: MODES 5 and 6 with pressurizer level ≤ 5%.

Question 26

If RCS pressure is ______, the _____ SI pump shall be available for accumulator fill. RCS pressure must be ______ to use the ___ SI pump.

Answer 26

<1700#; A; >=1700#; B

Question 27

Function of ECCS per 3.5.3 basis

Answer 27

The function of the ECCS is to provide core cooling and
negative reactivity to ensure that the reactor core is
protected after any of the following accidents:
a. Loss Of Coolant Accident (LOCA), coolant leakage
greater than the capability of the normal charging
system;
b. Rod ejection accident;
c. Loss of secondary coolant accident, including
uncontrolled steam release or loss of feedwater; and
d. Steam Generator Tube Rupture (SGTR).