Rx Trip

Question 1

For the Reactor Coolant Flow Rate - Low 2 Reactor Trip, what is the set point and coincidence?

Answer 1

90% (2/4 on 1/2) Hot Legs

Question 2

For the Pressurizer Pressure - High 2 Reactor Trip, what is the set point and coincidence?

Answer 2

2420.3 psig (2/4)

Question 3

For the Power Range Flux - High (High) Reactor Trip, what is the set point and coincidence?

Answer 3

109 % RTP (2/4)

• Note:*
• C-2 /// PR Flux ≥103 % RTP (2/4)*
• Blocks auto / manual Rod withdrawal for:*
• M Banks
• AO Banks

Question 4

When are the DAS Rx trips applicable?

Answer 4

Mode 1

TRM 3.3.1 DAS Automatic Actuation

Located in Note

Question 5

The Source Range Flux - High reactor trip is applicable in what mode(s)?

Answer 5

Mode 2 w/ IR neutron flux < P-6

Mode 3 - 5:

• PLS capable of rod withdrawal
  OR
• ≥ 1 rod not fully inserted

​LCO 3.3.2 RTS Source Range Instrumentation

P-6 /// Divisional IR ≥ 1 E-5% RTP

Question 6

What is the purpose / function of the DAS reactor trips?

Answer 6

Satisfies 10 CFR 50.62 (ATWS Rule)

Provides margin in the PRA

Question 7

For the Intermediate Range Flux - High Reactor Trip, what is the set point and coincidence?

Answer 7

25 % RTP (2/4)

Note:

• C-1 /// IR Flux ≥15 % RTP (2/4)*
• Blocks auto / manual rod withdrawal for:*
• M Banks
• AO Banks
• Manual Block: ≥ P-10*
• Auto Unblock: < P-10*
• • *

P-10 /// Divisional PR ≥ 10 % RTP

Question 8

For the Power Range Positive Flux Rate - High Reactor Trip, what is the set point and coincidence?

Answer 8

12 % RTP w/ 60 sec TC (2/4)

Question 9

The Intermediate Range Flux - High reactor trip is applicable in what mode(s)?

Answer 9

Mode 1 w/ PR Neutron Flux < P-10

Mode 2

LCO 3.3.3 RTS IR Instrumentation

P-10 /// Divisional PR ≥ 10% RTP

Question 10

Which reactor trip(s) protect the plant from an uncontrolled reactivity accident?

Answer 10

Low

Source Range Flux - High (< P-6)

• 1x10⁵ CPS (2/4)*
• • *

Mid

Intermediate Range Flux - High (≥ P-6 / < P-10)

25 % RTP (2/4)

Power Range Flux - High (Low) (≥ P-6 / < P-10)

• 25 % RTP (2/4)*
• • *

High

Power Range Flux - High (High) (≥ P-10)

109 % RTP (2/4)

Power Range Positive Flux Rate (High) (≥ P-10)

• 12% RTP w/ 60 sec TC*
• • *

P-6 /// Divisional IR ≥ 1 E-5 % RTP

P-10 /// Divisional PR ≥ 10 % RTP

Question 11

What are all the PMS Reactor Trips?

Answer 11

Power:

1. Source Range Flux - High
2. Intermediate Range Flux - High
3. Power Range Flux - High (Low)
4. Power Range Flux - High (High)
5. Power Range Positive Flux Rate - High

RCP / Flow

1. RCP Bearing Water Temp - High 2
2. RCP Speed - Low 2
3. Reactor Coolant Flow Rate - Low 2

Calorimetric Comparison

1. Overtemperature ∆T (OT∆T)
2. Overpower ∆T (OP∆T)

Pressurizer

1. Pressurizer Pressure - Low 2
2. Pressurizer Pressure - High 2
3. Pressurizer Water Level - High 3

Steam Generator

1. SG NR Water Level - Low 2
2. SG NR Water Level - High 3

System / Manual

• Safeguards (Manual / Auto)
• ADS (Manual / Auto)
• CMT (Manual / Auto)
• PRHR (Manual / Auto)
• Manual

Question 12

Which PMS Reactor Trips are interlocked with P-9 (Divisional T_avg ≥ 200°F)?

Answer 12

SG NR Water Level - Low 2

Manual Block < P-9 / Auto Unblock ≥ P-9

21 % (2/4 on 1/2)

P-9 /// Divisional T_avg ≥ 200°F

Question 13

For the Source Range Flux - High Reactor Trip, what is the set point and coincidence?

Answer 13

1 E5 CPS (2/4)

Manual Block ≥ P-6

Auto Block ≥ P-10

Auto Unblock < P-6

P-6 /// Divisional IR ≥ 1 E-5 % RTP

P-10 /// Division PR ≥ 10 % RTP

• Note:*
• Blocking Source Range Flux - High de-energizes source range nuclear instrument.*

Question 14

For the Power Range Flux - High (Low Setpoint) Reactor Trip, what is the set point and coincidence?

Answer 14

25 % RTP (2/4)

Question 15

For the SG WR Level - Low DAS Reactor Trip, what is the set point and coincidence?

Answer 15

26 % (1/2 on 2/2) TD

Question 16

Which PMS Reactor Trips are interlocked with P-11 (Divisional PZR pressure ≤ 1970 psig)?

Answer 16

SG NR Water Level - High 3

(Manual Block ≤ P-11 / Auto Unblock > P-11)

P-11 is used to allow rod testing in cold wet layup

P-11 /// Divisional Pzr Pressure ≤ 1970 psig

Question 17

For the Pressurizer Water Level - High 3 Reactor Trip, what is the set point and coincidence?

Answer 17

71 % (2/4)

Question 18

What are all the DAS Reactor Trips?

Answer 18

PZR Level - Low

SG WR Level - Low (TD)

Hot Leg Temperature - High

Manual

Question 19

For the Pressurizer Pressure - Low 2 Reactor Trip, what is the set point and coincidence?

Answer 19

1915 psig (2/4)

Question 20

For the SG NR Water Level - Low 2 Reactor Trip, what is the set point and coincidence?

Answer 20

21 % (2/4 on 1/2)

Question 21

With regards to how the reactor is tripped, how does the PMS and DAS trips differ?

Answer 21

PMS opens the reactor trip breakers

DAS opens rod control MG set field breakers

• Note:*
• DAS also trips the turbine on a TD*

Question 22

For the RCP Speed - Low Reactor Trip, what is the set point and coincidence?

Answer 22

91 % (2/4)

Question 23

For the RCP Bearing Water Temp. - High 2 Reactor Trip, what is the set point and coincidence?

Answer 23

185ºF (2/4 on 1/4)

Question 24

Which reactor trip(s) protect the integrity of the fuel?

Answer 24

Overpower ∆T (OP∆T)

Question 25

For the SG NR Water Level - High 3 Reactor Trip, what is the set point and coincidence?

Answer 25

**82 % (2/4 on 1/2)**

Question 26

Which reactor trip(s) protect the plant from reaching DNB?

Answer 26

**RCP bearing water temperature - High 2** **Reactor coolant flow rate - Low 2** **RCP Speed - Low 2** **Overtemperature ∆T (OT∆T)** **Pressurizer Pressure - Low 2**

Question 27

For the Overpower ∆T (OP∆T) Reactor Trip, what is the set point and coincidence?

Answer 27

**q∆T (calorimetric) ≥ OP∆T (2/4)** ≈109 % RTP * * * * Note:* * C-4 /// OP∆T ≥ 1% below Rx Trip* * Blocks auto / manual rod withdrawal for:* * *M Banks* * *AO Banks* *_Actuates Turbine Runback (Clears when C-4 clears)_*

Question 28

What interlocks are associated with the Source Range Flux - High PMS Reactor Trip?

Answer 28

**Manual Block ≥ P-6** **Auto Block ≥ P-10** **Auto Unblock \< P-6** * * * P-6 /// Divisional IR ≥ 1 E-5 % RTP P-10 /// Divisional PR ≥ 10 % RTP * * * * Note:* * Blocking Trip also de-energizes source range nuclear instruments*

Question 29

For the Overtemperature ∆T (OT∆T) Reactor Trip, what is the set point and coincidence?

Answer 29

**q∆T (Calorimetric) ≥ OT∆T (2/4)** ≈ 119% RTP ± penalties \< 5.6% COLR Figure 6 limit * * * * Note:* * C-3 /// OT∆T ≥ 1 % below Rx Trip* * Blocks auto / manual Rod withdrawal for:* * *M Banks* * *AO Banks* *_Actuates Turbine runback (Clears when C-3 clears)_*

Question 30

For the Hot Leg Temperature - High DAS Reactor Trip, what is the set point and coincidence?

Answer 30

**643 °F (2/2)**

Question 31

For the PZR Level - Low DAS Reactor Trip, what is the set point and coincidence?

Answer 31

**7.5 % (2/2)**

Question 32

Which PMS Reactor Trips are interlocked with P-10 (Divisional PR ≥ 10%)?

Answer 32

_Low Power_ 1. **Source Range Flux - High** (Auto Block ≥ P-10) 2. **Intermediate Range Flux - High** (Manual Block ≥ P-10 / Auto Unblock \< P-10) 3. **Power Range Flux - High (Low)** (Manual Block ≥ P-10 / Auto Unblock \< P-10) * * * _High Power_ 1. **Pressurizer Pressure - Low 2** (Auto Block \< P-10 / Auto Unblock ≥ P-10) 2. **Pressurizer Water Level - High 3** (Auto Block \< P-10 / Auto Unblock ≥ P-10) 3. **Reactor Coolant Flow Rate - Low 2** (Auto Block \< P-10 / Auto Unblock ≥ P-10) 4. **Reactor Coolant Pump Speed - Low 2** (Auto Block \< P-10 / Auto Unblock ≥ P-10) * * * P-10 /// Divisional PR ≥ 10 % RTP