Week 1: Reactor Vessel Internals

Question 1

Describe the flow and bypass flows through the Reactor Vessel.

Answer 1

96% through fuel
1% Nozzle bypass
2% RCCA and Instrument Thimble Bypass
0.5% Baffle wall
0.5% Upper Head Cooling

Question 2

How is the upper head attached to the reactor vessel?

Answer 2

54 head tensioning bolts

Question 3

How many penetrations are in the upper head? What are they?

Answer 3

79 total
53 CRDM
4 Incore thermocouple
1 RVLIS
1RCHVS
20 Spares

Question 4

Describe the seal between the upper head and the reactor vessel.

Answer 4

2 metal O-rings, outer and inner
2 sets of valves (inner and outer) connected to temperature sensors in order to detect leaks

Question 5

How many fuel assemblies are in a SNUPPS core?

Answer 5

193

Question 6

What is the average centerline fuel temperature? Hot rod temperature? Melting point of fuel?

Answer 6

Average is 1800F
Hot rod is 4200F
Melting Point is 4800F

Question 7

How many incore thermocouples are there? What is their purpose?

Answer 7

50; to measure fuel assembly outlet temperatures