AP-6 (Emergency Boration)

Question 1

AP-6

What are the two mechanisms (flow and concentration) that describe “emergency boration”?

What is thumbrule that equates to gallons of boric acid added to change [B] ppm?

Answer 1

>/= 30 gpm of 7000-7700 ppm [B]

> 90 gpm of 2300-2500 ppm [B]

9 gal/ ppm (for BAST)

Question 2

AP-6

what are the four methods (in preferred order) to emergency borate?

Answer 2

• Normal Boration via M/U control system
• open CVCS-8104 (Emergency Borate Valve)
• Swap charging suction to RWST (90 gpm)
• Locally open CVCS-8471 (manual emergency borate valve)

Question 3

AP-6

what are the entry conditions for Emergency Boration?

Answer 3

• Control rods below RIL (when critical)
• two or more rods fail to insert on Rx trip
• uncontrolled c/d on Rx trip (no ESFAS actuation)
• boration required and normal method (via VCT) not avail
• loss of SDM
• uncontrolled/ unexplained reactivity rise
  
  • control rod insertion
  • T_ave or Power rise (w/no rise in STM Dmd
  • rise in counts (when shut down)

Question 4

AP-6

If the rx trips and you have 3 stuck rods, how much are you required to borate?

If a load rejection caused rods to step in past RIL Lo-Lo alarm, how long do you have to initiate emergency boration?

Answer 4

400 ppm / stuck rod (1200 ppm)

or

2000 - 2400 ppm

whichever is less

1 hour