LOT 201.10 ECCS

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

• LOT 201.10 ECCS*
• • *

What fills/drains the accumulators?

Answer 2

# *_Fill:_*
HHSI

• Drain:*
• *RWST**
• *RCDT (Spoolpiece)**
• Complete Draining*
• *Primary Sampling**

Question 3

• LOT 201.10 ECCS*
• • *

In order for the RWST to be OPERABLE in MODES 1 - 4, what must water volume and boron concentration be?

Answer 3

≥ 458,000 gallons

2800 ppm - 3000 ppm

LCO 3.5.5 RWST

Applicable: MODES 1 - 4

Question 4

• LOT 201.10 ECCS*
• • *

In order for the accumulators to be OPERABLE in MODES 1 - 3 w/ PZR pressure > 1000 psig, what must water volume and boron concentration be?

Answer 4

• Water Volume:*
• *8800 gal - 9100 gal**
• Boron Concentration:*
• *2700 ppm - 3000 ppm**

LCO 3.5.1 Accumulators

Applicable: MODES 1 - 3

Question 5

• LOT 201.10 ECCS*
• • *

What valves in the ECCS have a power lockout feature?

Answer 5

• *HHSI/LHSI Hot leg injection valves (MOV-008/MOV-019)**
• 100% Power: Closed w/ power locked out*
• CP-001*
• *Accumulator outlet valves (MOV-039)**
• 100% Power: Open w/ power locked out*
• CP-001 / ASP*

No accumulator pressure / level indicators exist on ASP!!

• Note:*
• 2 transfer switches for accumulator outlet valves. 1 transfers control and VPI and the other transfers power lockout feature.*

Question 6

• LOT 201.10 ECCS*
• • *

What will auto open the accumulator discharge valve? (MOV-039)

Answer 6

SI

• *RCS Pressure ≥ P-11**
• PZR Pressure ≥ 1985 psig [2/3]*

Question 7

• LOT 201.10 ECCS*
• • *

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

Answer 7

• 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 8

• LOT 201.10 ECCS*
• • *

At what RCS pressures will the ECCS Accumulators, HHSI pumps, and LHSI pumps inject into the RCS Cold Legs?

Answer 8

• HHSI:*
• *< 1600 psig**
• Accumulators:*
• *590 - 670 psig**
• LHSI:*
• *< 300 psig**

Receive water from RWST.

• Note:*
• During DBA, Accumulators will inject 1^st.*

Question 9

• LOT 201.10 ECCS*
• • *

Where does HHSI and LHSI mini-flow valves discharge to?

Answer 9

RWST

Close on SI auto recirculation signal

Question 10

• LOT 201.10 ECCS*
• • *

Which valves will not be able to be manually opened if the respective train’s Emergency Sump Outlet Valve (MOV-016) is open?

Answer 10

HHSI Mini-Flow Valves (MOV-011/MOV-012)

LHSI Mini-Flow Valves (MOV-013/MOV-014)

RWST Outlet Valves (MOV-001)

To manually open Emergency Sump Outlet Valve:

• RWST Outlet Valve closed (Manual Only)
• HHSI Mini-Flow Valve closed [1/2]
• LHSI Mini-Flow Valve closed [1/2]

Question 11

• LOT 201.10 ECCS*
• • *

What are the four phases of a DBA LOCA?

Answer 11

• *Blowdown**
• Begins with LOCA and ends with RCS pressure = CTMT pressure*
• *Refill**
• Water at bottom of the reactor vessel and reaches the bottom of the fuel rods via addition of ECCS (Accumulators and SI pumps).*
• *Reflood**
• Rx vessel filled with water*
• Core temperature rise has terminated*
• Core temperatures have been reduced to their long term steady state level.*
• *Long Term Recirculation**
• Cold Leg Recirc (1^st Phase)*
• Hot Leg Recirc (2^nd Phase)*
• Hot Leg Recirc starts 5.5 hrs (Operator Action) after start of LOCA and cools upper head and prevents boron precipitation.*

Question 12

• LOT 201.10 ECCS*
• • *

What is the system lineup during hot leg recirc?

Answer 12

2 ECCS trains injecting into Hot Legs

1 ECCS train injecting into Cold Leg

LHSI and HHSI mini-flow valves closed

Taking Suction from Emergency Sumps

HHSI and LHSI are operated together. Never align HHSI to Hot leg and LHSI to Cold leg or vice versa.

• Note:*
• Cold Leg Recirc is the exact same except all 3 ECCS trains injecting into cold legs.*

Question 13

• LOT 201.10 ECCS*
• • *

What will cause an SI auto recirculation signal?

Answer 13

SI Signal

AND

• *RWST Level - Low 2 (≤ 75,000 gal) [1/1]**
• Each lvl switch provides signal for it’s train only*

Closes HHSI AND LHSI pump mini-flow valves.

When ≥ 1 valve for each pump closed:

• Opens containment sump → SI suction header Isolation valve.

RWST → SI suction header isolation valve must be manually closed by operator. (CP001)

• Note:*
• Reset and RWST lvl indication are located on CP001*

Question 14

• LOT 201.10 ECCS*
• • *

What cools the HHSI/LHSI upper and lower bearings?

Answer 14

Resevoir Oil Baths

Question 15

• LOT 201.10 ECCS*
• • *

When must all HHSI pumps be inoperable per tech specs?

Answer 15

• *MODE 5**
• *MODE 6 w/ Rx Vessel Head on**

LCO 3.5.3.2 ECCS Subsytems - T_avg ≤ 200 ˚F

Question 16

• LOT 201.10 ECCS*
• • *

When does the accumulator relief lift?

Answer 16

700 psig

Relieves to Containment Atmosphere

• HHSI Discharge Relief (1750 psig) → PRT
• LHSI Discharge Relief (600 psig) → PRT