ECCS

Question 1

What are the ECCS Injection order with pressures?

Answer 1

• CCP 2600#
• SI Pumps 1560#
• Accumulators 600#
• RHR Pumps 210#

Question 2

What is the ECCS Acceptance Criteria per 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

When RWST reaches low level (20%) and transfer to Recirc Sump

Question 4

What is the RWST Tech Spec Limit?

Answer 4

• 375,500 gallons
• 2400-2600 ppm boron
• 70-100°F

Question 5

When are the accumulators outlet valves open and deenergized?

Answer 5

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

Question 6

When do the accumulator outlets get an open signal?

Answer 6

SI sends signal to open outlet valves (IMO-110 thru IMO-140) to ensure any close valves will open

Question 7

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

Answer 7

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 8

What is the runout flow of the SI Pump?

Answer 8

700 gpm

Question 9

What is the normal position of IMO-262 and IMO-263 (SI Pump to RWST recirc valves)?

Answer 9

OPEN for standby readiness (for injection phase)

Question 10

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

Answer 10

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

Question 11

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

Answer 11

• Normally open for standby readiness to provide 4 loop injection on 1 SI Pump failure
• Closed during hot lleg recirc to prevent loss of both trains from single passive failure of SI pump discharge piping

Question 12

What will give you an SI signal?

Answer 12

• 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 13

What is the Tech Spec Basis for the RWST Level?

Answer 13

Level 375,500 gal - min level for recirc sump

Question 14

When do you align Hot Leg Recirc?

Answer 14

between 5.5 - 7.5 hrs after the LOCA.

Question 15

What is the reason for the time limitations associated with Hot Leg Recirc?

Answer 15

• Waiting at least 5.5 hours avoids core uncovery due to boil off. Enough decay heat has been removed
• Not exceeding 7.5 hours prevent boron precipitation in the reactor

Question 16

When do we initiate RHR Spray after an accident?

Answer 16

• Must be on the recirc sump AND > 50 mins after accident (ensures adequate injection for decay heat removal)
• If < 2 CTS running, the RHR Spray must be I/S in 75 minutes (limits can # and keeps CR dose < 5 rem TEDE.)

Question 17

What is the ECCS Leakage limits?

Answer 17

• Total unfiltered leakage from Recirc Loop < 0.1 gpm for Control Room dose
• < 2.0 gpm for containment sump water level analysis

Question 18

What are the applicable modes forTS 3.5.1 (Accumulators)?

Answer 18

Modes 1-3 with RCS Pressure > 1000#

Question 19

Per TS 3.5.2 (ECCS, operating), what must be done 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 ?

Answer 19

• IMMEDIATELY enter LCO 3.0.3

Question 20

What does TS 3.5.3 (ECCS, Shutdown) direct if rquired ECCS Train subsystem is inoperable in Mode 4?

Answer 20

IMMEDIATELY initiate action to restore required ECCS RHR/CCP subsystem to OPERABLE status

Question 21

What does TS 3.5.4 (RWST) direct if the RWST is inoperable for reasons other than boron concentraion or temperature?

Answer 21

WITH IN 1 Hr, restore RWST to OPERABLE status.

Question 22

Per TS 3.5.1 (Accumulators), what are the Accumulator parameters that must be maintained?

Answer 22

• Volume 921-971 cubic feet
• 585-658 psig
• 2400-2600 ppm Boron Concentration

Question 23

What is the the tech spec basis for the RWST Temperature band?

Answer 23

• Temp 70°F - Lower ΔP rcs vs cntmt - backpressure
• Temp 100°F - Prevents Peak # in Ctmnt to < 12#

Question 24

What is the tech spec basis for the RWST Boron Concentration band?

Answer 24

• Boron > 2400 ppm - ensure subcriticality
• Boron < 2600 ppm – max time to HL recirc

Question 25

When is RHR spray not required?

Answer 25

If containment # < 1.5#

Question 26

What are the ECCS Auto Actions on a Safety Injection?

Answer 26

• RWST to CCP isolation valves open; VCT outlet valves close
• CCPs start
• CCP ELOs close
• Charging header isolation valves close
• BIT inlet and outlet valves open
• SI pumps start
• RHR pumps start
• Any closed accumulator isolation valve opens

Question 27

Where do the Charging Pump ELOs receive their pressure signals from?

Answer 27

East Charging Pump - QMO-225 from NPP-151
West Charging Pump - QMO-226 from NPP-153

Question 28

What is filtered leakage?

Answer 28

There is communication with AES Fan.

Question 29

If in the applicable modes, what does TS 3.5.1 (Accumulators) direct if 2 or more accumulators are inoperable?

Answer 29

IMMEDIATELY enter LCO 3.0.3

Question 30

Per TS 3.5.2 (ECCS - Operating), what is considered a Train for OperabilitY?

Answer 30

CCP, SI and RHR

Question 31

Per TS 3.5.3 (ECCS - Shutdown), what is considered a Train for Operability?

Answer 31

CCP and RHR