Intro to ECCS - 1.0

Question 1

What are the ECCS Acceptance Criteria?

Answer 1

1. Cladding temperature does not exceed 2200°F.
2. Cladding oxidation shall not exceed 17% of cladding thickness.
3. Collable geometry.
4. H2 generation from zirc/water reaction shall not exceed 1% of the amount generated if all clad reacted.
5. Long term cooling.

Question 2

What is the DBA LOCA criteria?

Answer 2

1. Reactor initially at 102% rated thermal power (3917 MWth).
2. Loss of offsite AC power
3. Instantaneous, complete circumferential break of a recirculation pipe at the suction nozzle.
4. Loss of a channel A DC source (disabling HPCI, one loop of Core Spray, and one loop of LPCI)

Note: The initial reactor power used in the DBA LOCA Containment analyses is 105% (4031 MWth).

Question 3

What are the ECCS systems and what are their ratings?

Answer 3

1. HPCI – Designed for breaks < 1” in diameter.
   
   • 3000 gpm - A CS line, 2600 gpm – A FW line, Initiates -38”, 1.68#, manual
2. Core Spray – Two 100% capacity loops.
   
   • 3175 gpm per pump (6350 gpm per loop), 461 psi inj open permissive, 380 psi shutoff head.
3. LPCI – Four 100% capacity loops.
   
   • 10000 gpm (x4), 450 psi inj permissive, 340 psi shutoff head (171 psi for rated flow). -129”, 1.68#
4. ADS – Assist HPCI by depressurizing the plant in the event of a small break LOCA where HPCI cannot maintain level.
   
   • A thru E SRV’s used to depressurize RPV on -129 and 1.68 psi drywell (or timer)

Question 4

How much time do you have to respond to a DBA LOCA?

Answer 4

10 mins.