CBS

Question 1

STATE the function of the containment building spray system

Answer 1

• Limits peak containment building pressure / temperature following DBA LOCA or MSLB to < 52 psig
• Reduces concentration of fission product iodine in the containment atmosphere following LOCA (fuel rod rupture)

Question 2

DRAW a simplified diagram of the Containment Building Spray System including

Answer 2

pumps
key valves (including those actuated by a CSAS signal)
spray additive tank
refueling water storage tank
recirc sumps
heat exchangers
spray rings
connections with CS/SI/RH systems

Question 3

STATE the function of the following component CBS pumps

Answer 3

Designed to take suction from the Containment sump at the most limiting net positive suction head (NPSH) condition (atmospheric pressure and a temperature of 212°F) and pump it back into the Containment through the spray nozzles

Question 4

STATE the function of the following component Spray additive tank

Answer 4

Provides the source of Sodium Hydroxide (NaOH) to be added to RWST for Iodine removal inside containment

Question 5

STATE the function of the following component CBS heat exchangers

Answer 5

Provides Containment heat removal

Question 6

STATE the function of the following component CBS spray rings

Answer 6

Positioned to maximize coverage of the containment volume (@85% of total surface area.
4 Separate headers 2/Train
• 198 Nozzles /Train
• 15.2 GPM / Nozzle

Question 7

DESCRIBE design features that prevent debris from entering the recirculation sumps

Answer 7

• Heavy particles are prevented from reaching the sumps by sloping the surrounding floor away from the sumps.
• A vertical trash rack is provided to protect the fine inner screen from large floating particles.
• System of debris interceptors (DIs) on the containment floor
• high surface area recirculation sump screens

Question 8

EXPLAIN how the Containment Building Spray system is filled and vented

Answer 8

Gravity fill and vent CBS and RHR simultaneously from the RWST
Static vent fill / vent of the lines without using the pumps
As part of the static fill / vent, perform ultrasonic testing of piping to ensure piping is full of water
Dynamically vent the system using the pumps

Question 9

EXPLAIN how to fill and recirculate the spray additive tank

Answer 9

• Can fill SAT With Sodium Hydroxide (NaOH) from a fill truck or portable drums.
• Recirculating SAT
• Perform valve line up
• Start recirculation pump

Question 10

Discuss the personal protection requirements that should be used when handling NaOH

Answer 10

• Sodium hydroxide (NaOH) is extremely corrosive. It will cause severe chemical burns to any part of the body it contacts.
• Protective clothing as described below shall be worn by the operator, Radwaste, the truck driver and any other Seabrook Station personnel entering the roped-off area.
• Minimum protective clothing requirements are as follows:
• Acid Suit
• Hard Hat
• Chemical Boots
• Chemical Gloves
• Full Face Shield without chin deflector and goggles
OR
• Full Face Shield with beige chin deflector and Safety Glasses

Question 11

DESCRIBE the NSO’s actions on performing the CBS pump test

Answer 11

• NSO perform CBS Pump pre-starts
• CRO start CBS Pump
• NSO Verify recirc flow
• NSO Gather pump data

Question 12

DESCRIBE the NSO’s actions on isolating the CBS system

Answer 12

• ≤200°F, CBS is removed from service to prevent inadvertent spray actuation.

1) CBS Pumps are placed in PTL and breakers are racked out.
2) CBS-V-39 and CBS-V-44 are locked shut (SAT gravity drain manual isolation valve).
3) CBS-V-13 and CBS-V-19 are locked shut (spray header manual isolation).