Decrease in Inventory TAA

Question 1

For a LCLOCA what is the assumed failure and why?

Answer 1

• LOOP

- has adverse impact on core re-flood

Question 2

For a LBLOCA, what is the Design SI Flow Assumptions?

Answer 2

• 75% flow from 2 HPSI (25% out the break)
• 100% flow from 1 LPSI
• 50% flow from 1 LPSI
• 100% from 3 SITS

Question 3

For a SBLOCA what is the assumed failure?

Answer 3

• LOOP & loss of 1 DG

Question 4

What is the design criteria for ECCS?

Answer 4

• Max cladding temp - ≤ 2200°F
• Oxidation of cladding - ≤ 17%
• ≤ 1% of cladding reacts to produce H2
• Maintain coolable geometry
• Long-Term cooling

Question 5

During a SBLOCA what is credited for the RCS Heat Removal Safety Function management?

Answer 5

SBLOCA

• 2 phase natural circ
• SI Flow
• SG’s

LBLOCA

• ECCS thru core and out break
• SDC HX once on recirc (RAS)

Question 6

When is an RCS cooldown performed following a LOCA?

Answer 6

• 1 Hour

Question 7

During a LOCA, what is the purpose of CS?

Answer 7

• CTMT integrity
• Prevents H2 gas pockets (mixes atm)
• Scrubs Iodine from atm

Question 8

For Decrease in Inventory TAA, what is the assumed failure for a LD line break outside of CTMT?

Answer 8

CHB-515 does NOT auto close on High RHX outlet temperature

Question 9

How long do you have to isolate a LD leak outside of CTMT?

Answer 9

• 10 minute TCA

Question 10

What are the 5 phases of mass energy release during a LOCA?

Answer 10

Blowdown Phase - Initial leak, cladding cooled by leakage
Refill phase - Refilling core downcomer, not fuel cladding heats up
Re-flood phase - SITS refill core cladding begins cooling
Post Re-flood phase - Total core coverage with HPSI/LPSI
Long Term period - Restores CTMT press.