Loss of Flow TAA

Question 1

What are the limiting faults for Loss of Flow TAA?

Answer 1

• RCP Shaft Seizure

- RCP Shaft Break

Question 2

What is the MOST limiting event for Loss of Flow TAA

Answer 2

• Single RCP shaft break
  
  • Speed sensors unaffected
  • Allows for coast down of impeller
  • Longer RPS response time

Question 3

What is the ASSUMED single failure for a RCP shaft break

Answer 3

Stuck open ADV

• Allows any iodine in SG to be released to atmosphere
• Eventually drives SG to dryout

Question 4

What RPS trips will occur due to RCP shaft break & seize

Answer 4

Seize - CPC trip LO DNBR when <95% speed

Break - Low SG DP RPS trip