Section 3.5 Emergency Core Cooling System

Question 1

• LOT 201.10 ECCS*
• • *

What are the Emergency Core Cooling System (ECCS) acceptance criteria?

Answer 1

Coolable Geometry

Long-Term cooling

Cladding Oxidation
≤ 17% the total cladding thickness before oxidation.

• *Peak Cladding Temperature**
• ≤ 2200 ˚F*
• *H₂ Generation**
• ≤ 1% the total amount of H₂ produced from all metal surrounding the fuel reacting*
• (excludes metal around plenum volume)*

DBAs:

• LOCA
• SLB
• Fuel Handling Accident

Question 2

• LCO 3.5.2 ECCS Subsystems - T_avg ≥ 350 ˚F*
• • *

What is the acceptance criteria for D/P and flowrate for the HHSI and LHSI pumps?

Answer 2

D/P:
HHSI: ≥ 1480 psid
LHSI: ≥ 286 psid

Flowrate:
HHSI: 1470 gpm - 1620 gpm
LHSI: 2550 gpm - 2800 gpm

Question 3

• LCO 3.5.5 RWST*
• • *

What is the required water volume and boron concentration to make the RWST OPERABLE in MODES 1-4?

Answer 3

• Water Volume:*
• *≥ 458,000 gal**
• Boron Concentration:*
• *2800 ppm - 3000 ppm**

Bases:

• Will remain subcritical in cold shutdown condition following Large Break LOCA (All Rods Out)
• Will remain subcritical in cold shutdown condition following Small Break LOCA (All Rods In except most reactive rod)
• Ensures long term subcriticality following SLB (All Rods In except most reactive rod)
• Water Volume: Permit Recirc
• Boron: Determines time for hot leg recirc / keeps pH of sump 7.0 - 9.5

Question 4

• LCO 3.5.5 RWST*
• • *

When is LCO 3.5.5 RWST Applicable?

Answer 4

MODES 1-4

Question 5

• LOT 201.10 ECCS*
• • *

How do you place ECCS in-service during a plant heatup from cold shutdown?

Answer 5

• Mode 5:*
• *ALL HHSI pumps inoperable**
• *SI not blocked**
• Before Entering MODE 4:*
• *Open ALL HHSI CL injection valves**
• *2 trains of LHSI OPERABLE**
• Within 4 hrs of going > 200 ˚F and before exceeding 225 ˚F:*
• *1 HHSI OPERABLE and 1 HHSI in Standby**
• Before Entering MODE 3 (350 ˚F):*
• *ALL LHSI OPERABLE**
• Within 4 hrs of going > 350 ˚F and before exceeding 375 ˚F:*
• *ALL HHSI OPERABLE**
• 900 psig - 1000 psig:*
• *ALL Acummulators OPERABLE**

Question 6

• LCO 3.5.1 Accumulators*
• • *

What are your ≤ 1 hr action(s) if ≥ 2 accumulators are inoperable due to boron concentration?

Answer 6

• LCO 3.5.1 Accumulators*
• Action D*
• • *
• Restore boron concentration to make 2 accumulators OPERABLE [1 hr]

OR

• Apply CRMP [1 hr]

OR

• Be in MODE 3 [6 hrs]

AND

• Reduce PZR pressure < 1000 psig [Following 6 hrs]

Question 7

• LCO 3.5.3.1 ECCS Subsystems - T_avg < 350 ˚F*
• • *

What are your ≤ 1 hr action(s) if ≥ 2 ECCS trains are inoperable due to LHSI pumps or RHR HX’s in MODE 4?

Answer 7

• LCO 3.5.3.1 ECCS Subsystems - T_avg < 350 ˚F*
• Action B*
• • *
• Restore at least 2 ECCS trains [Immediately]

OR

• Remain < 350 ˚F T_avg by use of alternate heat removal [Immediately]

Question 8

• LCO 3.5.2 ECCS Subsystems - T_avg ≥ 350 ˚F*
• • *

What are your ≤ 1 hr action(s) if ≥ 1 ECCS subsystems are inoperable due to LOCA generated debris clogging the emergency sump while in MODES 1-3?

Answer 8

• LCO 3.5.2 ECCS Subsystems - T_avg ≥ 350 ˚F*
• Action C*
• • *
• Initiate action to implement compensatory actions [Immediately]

AND

• Restore flowpath to OPERABLE [90 days]

OR

• Be in MODE 3 [6 hrs]

AND

• Be in MODE 4 [Following 6 hrs]

Question 9

• LCO 3.5.3.1 ECCS Subsystems - T_avg < 350 ˚F*
• • *

What are your ≤ 1 hr action(s) if ≥ 2 ECCS trains are inoperable due to HHSI pumps or flowpath from RWST in MODE 4?

Answer 9

• LCO 3.5.3.1 ECCS Subsystems - T_avg < 350 ˚F*
• Action A*
• • *
• Restore at least 2 ECCS trains [1 hr]

OR

• Be in MODE 5 [20 hrs]

Question 10

• LCO 3.5.3.1 ECCS Subsystems - T_avg < 350 ˚F*
• • *

When is LCO 3.5.3.1 ECCS Subsystems - T_avg < 350 ˚F Applicable?

Answer 10

MODE 4

Question 11

• LCO 3.5.5 RWST*
• • *

What are your ≤ 1 hr action(s) if the RWST is inoperable while in MODES 1-4?

Answer 11

• LCO 3.5.5 RWST*
• Action A*
• • *
• Restore RWST to OPERABLE [1 hr]

OR

• Apply CRMP [1 hr]

OR

• Be in MODE 3 [6 hrs]

AND

• Be in MODE 5 [30 hrs]

Question 12

• LCO 3.5.2 ECCS Subsystems - T_avg ≥ 350 ˚F*
• • *

When is LCO 3.5.2 ECCS Subsystems - T_avg ≥ 350 ˚F applicable?

Answer 12

MODES 1-3

Question 13

• LCO 3.5.1 Accumulators*
• • *

When is LCO 3.5.1 Accumulators applicable?

Answer 13

MODES 1-2

MODE 3 w/ PZR Pressure > 1000 psig

Question 14

• LCO 3.5.2 ECCS Subsystems - T_avg ≥ 350 ˚F*
• • *

What are your ≤ 1 hr action(s) if ≥ 2 ECCS subsystems are inoperable while in MODES 1-3?

Answer 14

• LCO 3.5.2 ECCS Subsystems - T_avg ≥ 350 ˚F*
• Action B*
• • *
• Restore at least 2 subsystems to OPERABLE [1 hr]

OR

• Apply CRMP [1 hr]

OR

• Be in MODE 3 [6 hrs]

AND

• Be in MODE 4 [Following 6 hrs]

Question 15

• LCO 3.5.1 Accumulators*
• • *

What are your ≤ 1 hr action(s) if ≥ 2 Accumulators are inoperable for reasons other than boron concentration?

Answer 15

• LCO 3.5.1 Accumulators*
• Action B*
• • *
• Restore at least 2 accumulators to OPERABLE [1 hr]

OR

• Apply CRMP [1 hr]

OR

• Be in MODE 3 [6 hrs]

AND

• Reduce PZR pressure to < 1000 psig [Following 6 hrs]

Question 16

• LCO 3.5.6 RHR*
• • *

When is LCO 3.5.6 RHR Applicable?

Answer 16

MODES 1-3

Bases:

• Ensures adequate heat removal for long term core cooling (Small break LOCA, isolable LOCA, SLB)

Question 17

• LCO 3.5.6 RHR*
• • *

What are your ≤ 1 hr action(s) if all three RHR trains are inoperable while in MODES 1-3?

Answer 17

• LCO 3.5.6 RHR*
• Action C*
• • *

Initiate action to restore at least 1 train of RHR [Immediately]

Question 18

• LCO 3.5.1 Accumulators*
• • *

What is the required water volume, boron concentration, and pressure of the accumulators?

Answer 18

• Water Volume:*
• *≥ 8800 gal - ≤ 9100 gal**
• Boron Concentration:*
• *≥ 2700 ppm - ≤ 3000 ppm**
• Pressure:*
• *630 psig ± 40 psig**

Question 19

• LCO 3.5.3.2 ECCS Subsystems - T_avg ≤ 200 ˚F*
• • *

When is LCO 3.5.3.2 ECCS Subsystems - T_avg ≤ 200 ˚F Applicable?

Answer 19

MODE 5

MODE 6 w/ Rx Vessel Head on