CVCS Letdown

Question 1

What is the purpose of the LD coils

Answer 1

Allow decay of N16 gammas

a single 2” line splits into 2x16” 12ft pipes then recombines

Question 2

What is the purpose of CHN-PSV-345 Intermediate LD pressure relief

Answer 2

Protects piping b/w LD and B/P control valves

-Lifts at 600 psig

Question 3

What is the purpose of CHN-PSV-354 low press LD relief vlv

Answer 3

Protects boronometer from over pressure

-Lifts at 200 psig

Question 4

What is the purpose of CVCS

Answer 4

• Controls RCS purity, volume, boron concentration
• Maintains RCS chemistry, including pH
• Continuous removal of noble gasses
• Controls Boron to compensate for rx changes
• Boron concentration for SDM
• Provides Aux Spray for PZR
• Continuous measure of RCS fission products
• Provides RCP seal inj, and controls bleedoff
• Source of borated water for SI
• Source of water for refueling pool
• SDC purification

Question 5

How long can the RWT provide SI

Answer 5

At least 20 minutes plus 10% at full flow before reaching RAS

Question 6

What modification was performed to CHN-515, 516 & 523

Answer 6

Larger closing springs were installed

because of this the handwheels were removed due to the excessive force needed to operate.

Question 7

What automatic features are associated with CHN-515

Answer 7

Closes on:

• SIAS
• Regen HX out temp HI - 413*F

Question 8

What automatic features are associated with CHN-516

Answer 8

Closes on:

• SIAS
• CIAS

Question 9

What automatic features are associated with CHN-523

Answer 9

Closes on:

• CIAS
• LD HX out temp HI - 135*F

Question 10

What is the purpose of the Regen HX

Answer 10

• Conserve RCS thermal energy
• Minimize Thermal Shock on RCS inlet nozzle
• Maintain LD outlet temp <450*F

Question 11

What is the power supply to LD Control Valves

Answer 11

NNN-D11

Question 12

What is the power supply to the LD flow control Bypass valve

Answer 12

NK

Question 13

Why is only 1 LD Control vlv in service >1000 psia

Answer 13

to prevent exceeding capacity of CHN-PSV-345

Question 14

What is the purpose of CHN-526 LD Flow Control Bypass vlv

Answer 14

• 0.5 gpm flow

- Warms up Regen HX

Question 15

What is the purpose of the LD HX

Answer 15

continues to cool LD to <120*F to prevent damage to IX resin

Question 16

What is the power supply to the LD B/P control vlvs

Answer 16

NNN-D12

Question 17

What is the purpose of the LD B/P control vlvs

Answer 17

• controls B/P to prevent boiling in LD HX
• Maintains around 375 psig of B/P
• Helps control SDC flow
• B/U temp protection - Close @ 148*F

Question 18

What is the purpose of CHN-204 Boronometer flow control vlv

Answer 18

Maintains approx. 8 gpm flow through Boronometer and rad monitor line

Question 19

What is the purpose of CHN-521

Answer 19

• Protects the Boronometer from high temp

- Shifts at 135*F

Question 20

What type of monitor is the LD process monitor

Answer 20

General area gamma monitor

Question 21

What is the purpose of the LD rad monitor

Answer 21

• Detects possible fuel cladding failure

- Alarm is based on 1% failed fuel

Question 22

What is the purpose of CHN-520 IX bypass vlv

Answer 22

• Protects IX resin from high temps

- Bypasses at 135*F

Question 23

What is the concern with temp. changes and the CVCS IX’s

Answer 23

• As LD temp goes down MORE Boron is removed

- As LD temp goes up LESS Boron is removed

Question 24

What is the max LD IX flow and why

Answer 24

• 150 gpm

- to prevent channeling of the resin

Question 25

How is Li created in RCS

Answer 25

B10 captures a neutron and then decays

Question 26

When is the Deborating IX placed in service

Answer 26

- Near the end of core life | - 30-50 ppm boron