RWCU

Question 1

During RWCU Startup, When must a QNE be notified?

Answer 1

If unit is approaching criticality the QNE must be notified because start up of RWCU will add cold water to reactor whichw ill add positive reactivity

Also, RWCU blowdown may result in non-conservative heat balance calculation of core thermal power

Question 2

What are consequences of simultaneous RWCU blowdown to condenser and RW?

Answer 2

Loss of condenser vacuum is possible due to open path between condenser and radwaste

Question 3

Why is RWCU blowdown established and maintained prior to placing system in service?

Answer 3

To fill and vent 65 to 75 GPM for 15 minutes.
Ensures system is full and minimizes thermal transient effects. Following RWCU demin operations additional blowdown at 150 GPM to flush resin.

Question 4

What are the possible consequences of removing RWCU from service while Rx is at or near full power?

Answer 4

Plant thermal efficiency will go up to removal of heat loss

Question 5

What must be done for RWCU system when restoring system AFTER demin operations?

Answer 5

Blowdown to hotwell at >150GPM for >15 minutes to flush resin fines and lower conductivity out of resin beds

Question 6

What is impact on primary containment if RWCU system securred w/ Rx at rated pressure?

Answer 6

RWCU being secured removes large heat load from RBCCW.

May increase cooling to DW coolers causing drop in DW pressure

Question 7

What is concern w/ RWCU start?

Answer 7

Violating Thermal and Preconditioning limits

Question 8

What problem can cause use RWCU blowdown during power operation cause?

Answer 8

Non-conservative heat-balance of core thermal power

Question 9

If any thermal limit is greater than 0.95, what must be done prior to placing RWCU in service?

Answer 9

Contact QNE.

Reduce core thermal power to 97% to preven exceeding thermal power limit