LOT 201.03 Rx Vessel & Internals

Question 1

• LOT 201.03 Rx Vessel & Internals*
• • *

How much RCS flow bypasses the fuel?

Answer 1

8.5% bypass flow

• *Rx Vessel Head (2.5%)**
• *Fuel Thimble Guides (4%)**
• RCCAs (2%)*
• Sources / Poisons (2%)*
• *Between C_L and H_L nozzles (1%)**
• *Between Baffle Wall and Core Barrel Wall (0.5%)**
• *Between Baffle Wall and Fuel (0.5%)**

Question 2

• LOT 201.03 Rx Vessel & Internals*
• • *

If one level sensor in the Rx Vessel upper head were to dry out, what would indicated water level be?

Answer 2

64%

• Detectors are Heated Junction Thermocouples
• Works on ∆T. Detectors get uncovered ∆T↑(Detector Dry)

• Note:*
• Powered by “A” and “C” trains. DP001/DP002.*

Question 3

• LOT 201.03 Rx Vessel & Internals*
• • *

What is the definition of core alterations?

Answer 3

• Movement of:*
• *Fuel**
• *Sources**
• *Reactivity Control Components**
• Excludes RCCAs attached to integrated head*
• Applicable:*
• *Head Removed**
• *Fuel in Core**

• Note:*
• Put out in class that removing head is a core alteration.*

Question 4

• LOT 201.03 Rx Vessel & Internals*
• • *

What is the major design flaw with using Manganese Molybdemun for the Rx vessel?

Answer 4

Susceptible to boron corrosion

Lined with 5/32” stainless steel

Question 5

• LOT 201.03 Rx Vessel & Internals*
• • *

How many penetrations are there in the lower head?

Answer 5

58 penetrations

Used for incore nuclear instrumentation

Question 6

• LOT 201.03 Rx Vessel & Internals*
• • *

What are the RCCAs made of?

Answer 6

• *Silver-Indium-Cadmium**
• SIC Rods*

56 in Unit 1 (Rod D-6 removed)

57 in Unit 2

Question 7

• LOT 201.03 Rx Vessel & Internals*
• • *

How many penetrations are there in the upper head?

Answer 7

67 total penetrations

• *CRDMs**
• 57 penetrations ****
• *Core exit thermocouplets**
• 4 penetrations*
• *Internal disconnect device**
• 3 penetrations*
• *Rx Vessel Water Level**
• 2 penetrations*
• *Head Vent**
• 1 penetration*

Note:
56 penetrations for Unit 1. D-6 rod is not being used.

Question 8

• LOT 201.03 Rx Vessel & Internals*
• • *

What are the neutron sources made of?

Answer 8

• Primary Source:*
• *Californium-252**
• Used for initial S/U*
• Secondary Source:*
• *Antimony-Beryllium**
• Used for subsequent S/Us*
• Located in H-3 / H-13*

CF-252 burns itself up after 1^st S/U.

Antimony-Beryllium regenerates itself.