ECCS

Question 1

What are the ECCS Injection order with pressures?

Answer 1

• CCP 2300#
• SI Pumps 1600#
• Accumulators 600#
• RHR Pumps 200#

Question 2

What are the ECCS Design Criteria from 10CFR50.46?

Answer 2

• Peak clad temp < 2200°F
• Max cladding oxidation < 17%
• H2 concentration < 1%
• Core maintains cool able geometry
• Long term cooling provided

Question 3

When does the ECCS injection phase end?

Answer 3

• Injection phase ends when RWST reaches low level (20%) and transfer to Recirc Sump
  -Water level in Recirc Sump must be at least
  602’-2 3/4”

Question 4

What is the RWST Tech Spec Limit?

Answer 4

• 375,500 gallons - 1 Hr spec
• 2400-2600 ppm boron con - 8 Hr spec
• 70-100°F - 8 Hr Spec

Question 5

When are the accumulators outlet valves open and deenergized (i.e., required to be operable)

Answer 5

• Modes 1-2 and Mode 3 when Pzr # > 1000#

Question 6

How many accumulators are necessary to inject into the core? (FSAR Assumption)?

Answer 6

• 3 accumulators contain enough borated water to fill volume outside of the reactor core barrel, below nozzles, bottom plenum, and portion of the core* (Assumes one falls to the floor)

Question 7

What are the SI pump trips?

Answer 7

• Load Shed

- Overload/Overcurrent

Question 8

When are IMO-262 and IMO-263 (SI Pump to RWST recirc valves) open?

Answer 8

• Open on injection phase

Question 9

When do IMO-262 and IMO-263 (SI Pump to RWST recirc valves) auto close?

Answer 9

• Closed for cold leg recirc to prevent pumping recirc sump to RWST

Question 10

When are IMO-270 and IMO-275 (SI train x-tires) normally open and when are they closed?

Answer 10

• Normally open to provide 4 loop injection on 1 SI Pump failure
• Closed during cold leg recirc

Question 11

What will give you an SI signal?

Answer 11

• Pzr # Low - 1775# (2/3)
• Containment # High - 1.0# (2/3)
• S/G # Low - 500# (1/1 on 2 S/G)
• 1 S/G 100# ΔP lower than 2 others (2/3)

Question 12

What is the RWST Tech Spec Basis?

Answer 12

• Level 375,500 gal - min level for recirc sump
• Temp 70°F - Lower ΔP rcs vs cntmt - backpressure
• Temp 100°F - Prevents Peak # in Ctmnt to < 12#
• Boron > 2400 ppm - ensure subcriticality
• Boron < 2600 ppm – max time to HL recirc

Question 13

When do you align Hot Leg Recirc?

Answer 13

• Align before 7.5 hrs after the LOCA. (Prevent boron precipitation in the reactor)

Question 14

When do you NOT align Hot Leg Recirc?

Answer 14

• Do NOT align < 5.5 hours after the LOCA. (Avoid core uncovery due to boil off)

Question 15

When do we initiate RHR Spray after an accident and when is in required/not required?

Answer 15

• RHR Spray not initiated until > 50 min after accident (ensures adequate injection for decay heat removal)
• If < 2 CTS running RHR Spray must be I/S in 75 minutes (limits can # and keeps CR dose < 5 rem TEDE.)
• required for 6 hours after LBLOCA
• not required if containment # < 1.5#

Question 16

What is the ECCS Leakage limits for CR habitability?

Answer 16

• Total unfiltered leakage from Recirc Loop < 0.1 gpm for Control Room dose and < 2.0 gpm for containment sump water level analysis
• Filtered- Means there is communication with AES Fan.

Question 17

What does TS 3.5.1 (Accumulators) state?

Answer 17

• If 2 or more accumulators are inoperable in Modes 1-3 with RCS Pressure > 1000#
  IMMEDIATELY
• enter LCO 3.0.3

Question 18

What does TS 3.5.2 (ECCS, operating) state?

Answer 18

• If 1 of the ECCS flow is < 100% equivelant to a single Operable ECCS train available for reasons other than having 1 or more SI Systems x-tie valves closed
  IMMEDIATELY
• enter LCO 3.0.3

(3.5.2: 1 Train = CCP, SI and RHR)

Question 19

What does TS 3.5.3 (ECCS, Shutdown) state?

Answer 19

• If Required ECCS Train (RHR or CCP) subsystem inoperable in Mode 4
  IMMEDIATELY
• enter Initiate action to restore required ECCS RHR/CCP subsystem to OPERABLE status (CCP - 1 hr, RHR - immediately)

Question 20

What does TS 3.5.4 (RWST) state?

Answer 20

• If the RWST is inoperable for reasons other than boron concen or temp then
  WITH IN 1 Hr
• restore RWST to OPERABLE status.

Question 21

What are the Accumulator parameters?

Answer 21

• Volume 921-971 cuft
• 585-658#
• 2400-2600 ppm Boron