ECCS

Question 1

State 4 accident conditions that form basis of ECCS

Answer 1

Loss of Primary Coolant (greater than 125gpm)
Loss of secondary coolant (FW/MS)
SG tube rupture
Rod ejection accident

Question 2

State 5 ECCS acceptance criteria

Answer 2

Peak cladding temp <2200F
Total Cladding oxidation <17% of thickness
Total hydrogen production <1% of max
maintain coolable geometry
Long term cooling

Question 3

State what actuates SI

Answer 3

Low PZR pressure <1800# (2 of 4)*
Hi-1 containment pressure >4.3# (2 of 3)
Low MS line pressure <585# (2 of 3 on 1 of 4 S/G)*
Manual
* Blockable by P-11

Question 4

Discuss SI reset

Answer 4

60 second timer after actuation
With SI reset all subsequent Auto SI actuations are blocked
With RX trip breakers open (P-4) auto SI blocked after SI reset

Question 5

Define active failure and state worse case scenario for Seabrook

Answer 5

A failure of a powered component to act on demand

Worse case: EDG fails to start

Question 6

Define passive failure and state worse case scenario for Seabrook

Answer 6

A structural failure of a static component which limits effectiveness in performing its design function (flanges, seals, packing)
Worse case: RHR pump shaft seal failure (50GPM leak)

Question 7

State ECCS injection pressures

Answer 7

HHI: (CCP) 2600#
IHI: (SI) 1530#
Accumulators: 600#
LHI: (RHR) 200#

Question 8

State SI accumulators T.S. basis

Answer 8

Low level: 6121 Gal, insufficient volume
High level: 6596 Gal, insufficient gas volume causing premature exhaustion
Low Pressure: 585#, insufficient gas volume causing premature exhaustion
High Pressure: 664#, premature injection and more water out break

Question 9

Describe CCP recirc flow

Answer 9

min flow returns to pump suction via seal water return line
Recirc closes at >122.5 GPM
Recirc opens at <82.5 GPM

Question 10

Describe SIP recirc flow

Answer 10

min flow returns to RWST vis SI-V-89,90 and 93

Question 11

Describe RHR recirc flow

Answer 11

From the discharger of the RHR HX back to the pump suction
Auto open <750 GPM
Auto Closed >1403 GPM

Question 12

State what PCCW supplies to ECCS components

Answer 12

CCP: oil cooler (65 GPM)
SIP: oil cooler (45 GPM)
RHR: Seal water HX (6 GPM)
RHR-HX

Question 13

Discuss how HHI responds to a SI signal

Answer 13

CCPs start
CS-LCV-112D/E open, suction from RWST
CS-LCV-112B/C close, suction from VCT
SI-V-138,139 open, RCS injection header isolations
CS-V-142/143 close, Charging header isolation
CS-V-196/197 close, CCP minflow if >122.5GPM

Question 14

Discuss how IHI responds to a SI signal

Answer 14

SIPs start

Question 15

Discuss how LHI responds to a SI signal

Answer 15

RHR pumps start
CBS-V-2/5 open, RWST outlet, normally open
CC-V-145/272 open, PCCW to RHR HX, normally open

Question 16

What happens if offsite power is lost after SI is reset

Answer 16

manual action may be required to restart safeguards equipment

Question 17

Discuss interlock between SIP minflow and RHR to CCP/SIP isolation

Answer 17

SI-V-89 and 90 or 93 must be closed to open RH-V-35/36
AND
CBS-V-8/14 must be open
AND
RC-V-22 or 23 AND 87 or 88 must be closed
This prevents a loss of inventory to RWST
also prevents moving highly contaminated water to RWST.

Question 18

State T.S. values for RWST per T.S. 3.5.4

Answer 18

Volume: 477,000 Gallons
Low Temp: 50F
High Temp: 98F
Boron concentration per COLR (2500-2600)

Question 19

State T.S. actions for RWST inop

Answer 19

Restore the tank to operable within 1 hour or be in at least hot standby within 6 HRs and cold shutdown in the following 30 HRs.

Question 20

State basis for RWST pH per T.S. 3/4.5.4

Answer 20

pH between 8.5 and 11 to keep Iodine in solution and prevent corrosion

Question 21

When and why do we go to hot leg recirculation

Answer 21

5 hours after event to prevent boron precipitation

quench steam bubble and avoid boron precipitation

Question 22

State RWST Lo-lo level and action

Answer 22

120,478 Gallons

• CBS-V-8/14 open
• have to manually close CBS-V-2/5

Question 23

State reason for SI-V-93 control power switch and how to operate

Answer 23

Prevents single failure from causing valve movement and requires operator to perform 2 manipulations, this would inop both pumps
- turn CS to desired position and then turn control power (left to right)