201.03 Rx Vessel & Internals Flashcards

1
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Approx. dimensions of Rx Vessel

A

42.6’ high x 14.4 wide (i.d)

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2
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Materials used to make Rx Vessel & Internals

A

Manganese Molybnenum

with

304 SS Clad approx. 5/32”

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3
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Nozzle Dimensions

A

Inlet - 27.5 “

Outlet - 29”

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4
Q
  • 201.03 Rx Vessesl & Internals*
    • *

How is the vessel supported?

A

Two hot legs and two cold legs are supported within primary shield wall on support shoes

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5
Q
  • 201.03 Rx Vessesl & Internals*
    • *

How is the head bolted?

A

Roto-lock head bolts use lugs instead of conventional threads to engage flange and attach stud tensioner. Conventional threads for nut.

  • Liberal clearances, no galling*
  • Quick installation of stud tensioners*
  • Time spent in Vicinity of Vessel is reduced by a factor of six*
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6
Q
  • 201.03 Rx Vessesl & Internals*
    • *

How is the head sealed?

A

Two hollow, pressurized o-rings with two drain lines (1 outside, 1 inbetween). Common temp switch warns of leakage at 20 F above ambient

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7
Q
  • 201.03 Rx Vessesl & Internals*
    • *

What are the head penetrations used for?

A

58 in lower head - incore NIs

67 in upper head

57 - CRDMs

4 - CETs

3 - internals disconnect device

2 - RVWL instrumentation

1 - Head Vent

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8
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Purpose of vessel specimens

A

Metal specimens from same batch as vessel are placed between core barrel and vessel wall. Periodically tested to ensure vessel embrittlement is as expected.

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9
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Head and Vessel Alignment Pins

A

Four Manganese Molybdenum pins keep head aligned during assembly

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10
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Core Barrel

A

Two-section welded SS cylinder accommodates fuel assemblies

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11
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Radial Support

A

6 inconel keys on core support forging fit into 6 keyways welded around periphery of vessel to provide radial support and alignment

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12
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Thermal Shield

A

304 SS pad reduces gamma heating and neutron embrittlement of the vessel

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13
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Lower Core Support Plate

A

20” SS forged plate supports weight of fuel assemblies and directs uniform flow through the core

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14
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Baffle and Former

A

SS, bolted to circular core barrel to transition to squared off core periphery

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15
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Instrument Thimble Guides

A

SS, guide and support incore NIs

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16
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Secondary Support Assembly

A

SS, limits stress on lower head if internals dropped from core barrel or flange failure

17
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Upper Support Assembly

A

SS, provides axial support for upper core plate and support columns

18
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Internal Support Ledge

A

supports all weight of reactor internals and core

19
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Support Columns

A

50 SS columns establish spacing for upper core plate and support assembly

20
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Control Rod Guide Tubes

A

Sheath and guide RCCAs and drive shaft

21
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Upper Core Plate

A

Radial support to RCCA guide tubes and fuel assemblies

Directs flow from fuel assemblies to outlet plenum

22
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Fuel Enrichment & Location Pattern

A

varied for even power distribution (flatter flux profile) and fuel burnup

23
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Fuel Assembly

Bottom nozzle

A

box-like structure that distributes flow through the assembly

24
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Fuel Assembly

Top Nozzle

A

Protects rodlets from coolant cross-flow

Directs flow through upper core plate

25
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Fuel Assembly

Hold Down Springs

A

4 springs per assembly provide hold down force

26
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Fuel Assembly

Rod Guide Thimbles and Dash Pot

A

Provide guide channels for control rods. Lower 39” smaller diameter to provide hydraulic cushion for dropped rod

27
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Fuel Assembly

Grid Assembly

A

10 per assembly for lateral support and proper rodlet positioning. Mixing vanes stick out into coolant flow to cause turbulent flow and insrease heat transfer.

28
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Fuel Assembly

Incore Detector Thimbles

A

Located in center of each fuel assembly for incore instrument guide tubes

29
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Fuel Assembly

Fuel Rods

A

Zirc 4 tubing plugged and seal welded to encapsulate fuel pellets

30
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Fuel Assembly

Fuel Pellet

A

Uranium Dioxide with dished ends to allow axial expansion

31
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Burnable Poison Rods

A

Not currently used.

integral Fuel Burnable Absorbers (IFBAs) consiting of B-10 coatings on fuel pellets in selected fuel rods currently used

32
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Secondary Sources

A

Antimony-Beryllium regenerative sources located in locations H-3 and H-13 provide detectable neutron levels while shutdown

33
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Rod Control Cluster Assembly

A

57 RCCAs with 24 rodlets each

Silver - Indium - Cadmium

held in proper positions for insertion or withdrawl by spider assembly

34
Q
  • 201.03 Rx Vessesl & Internals*
    • *

RVWL

A

Heated junction thermocouple assemblies sense temp difference as water covers sensor. 2 channels of 8 sensors:

2 in upper head - 100% and 64%

Plenum - 100%

Top of Hot Leg - 85%

Middle of Hot Leg - 66%

Bottom of Hot Leg - 48%

b/w bottom of Hot Leg and Upper Core Alignment Plate - 33%

just above Upper Core Alignment Plate - 20%

35
Q

RVWL Operability and operation

A

A channel is OPERABLE if four or more sensors, one or more in upper section and three or more in lower section, are OPERABLE.

Minimum of 1 OPERABLE channel

Displays on QDPS and ICS

  • >200 F delta between heated an unheated indicates uncovered*
  • <25 F - shorted, > 2300 F - open*
36
Q
  • 201.03 Rx Vessesl & Internals*
    • *

Core Bypass Flows

A

8.5 % total bypass flow:

  1. 5% through bypass nozzles cool Rx Vessel Head
  2. 0% through thimbles with RCCAs cool control rods
  3. 0% through thimble guide tubes with no RCCAs, sources, poisons, or thimble plugs
  4. 0% between cold and hot leg nozzles
  5. 5% between baffle wall and core barrel
  6. 5% between fuel and baffle wall