NOTE: The parameters listed here take into account all features of the reactor presently in operation or under construction.


Reactor type Fissionable material: 1.3 - 2.25 wt U-235
Moderator 99.73% D2O; Reflector 99.73%D2O
Coolant - By weight - 70% Monsanto OS84
                                 30% Radiolytic Tars
Nominal Reactor Power 60 MWth
Purpose Engineering test of coolant materials, coolant tube materials, coolant tube design, fuel materials, fuel cladding materials, and fuel design.
Designers & Builders Reactor Plant - Canadian General Electric
Building - Shawnigan Engineering
Construction Schedule Start of construction - 1963
Reactor Critical - November 1, 1965
Full Power - January 1966
Mean Neutron Energy in the Core Thermal
Mean Lifetime of Prompt Neutrons 5.2 x 10-4 sec
Core Parameters Note: These parameters are dependent on moderator height, core enrichment, fuel burnup, and moderator boron concentration.
For a unit cell (hot, fresh fuel, 2.25 wt% U-235, small calandria tube, 1.0 ppm Boron-10 in moderator):
e = 1.029
n = 1.644
p = 0.908
f = 0.904
L2 = 127.2 cm2
L2s = 125.1 cm2
Fast leakage factor = 0.939
Thermal leakage factor = 0.938
Neutron Flux Thermal average ~ 5 x 1013 n/cm2 sec
Thermal maximum ~ 1.5 x 1014 n/cm2 sec
Excess Reactivity Balance Xenon (100% R.P.) - 27.2 mk
Fuel burnup - 0.4 mk/Full Power Day
Maximum Excess Reactivity Built-in 93 mk (52 in. to 96 in. moderator height)


Shape and Dimensions Cylindrical. Maximum Height 96 ins. (244 cm)
Operating Height 89 ins. (226 cm)
Radius 35.36 ins. (89.8 cm)
Channels and Assemblies in Core Normal coolant circuits: 49
Experimental Loops: 4
Capsule Facility: 1
Self-powered flux detectors: 1
Standard Channel Material: Ozhenite 0.5
I.D. 3.263 in. (8.29 cm)
Wall thickness: 0.125 in. (0.32 cm)
Standard Assembly Height: 97.5 in. (248 cm)
O.D. 3.23 in. (8.2 cm)
Lattice Hexagonal - Pitch 9.25 in. (23.5 cm)
Critical Mass (Cold Unpoisoned):
23.3 kg U-235 (19 site core 84.3 in. moderator height)
21.8 kg U-235 (25 site core 59.2 in. moderator height)
Average Specific Power in Fuel 1.1 MW/fuelled site (at full power, 89 in. moderator height)
4.8 kW/cm fuel
Average Power Density of Core 294 W/cm3 of fuel (at full power, 89 in. moderator height)
Moderator 16.6 Mg D2O, 99.73% pure, liquid
Average Temperature: 10oC
Maximum Temperature: 30oC
Flow Rate 0.040 m3/s
Cooling by heat exchanger
Blanket Gas Helium


Meat Cast UC slugs, cylindrical sheath.
Cladding Zr-2.5 Nb
Elements Sheath O.D. 0.530 in. (1.35 cm)
Fuelled length 18.78 in. (47.7 cm)
Total length 19.5 in (49.5 cm)
Subassemblies [bundles] 14 elements/bundle - uniformly spaced in a single ring circular lattice.
Centre position contains hollow Zr-2.5 Nb support rod.
Assemblies Length of fuel end ~97.5 in. (248 cm)
Length of fuel assembly ~19 ft (580 cm)
Burnup Rated average 360 MWh/kgU
Fuel Loading & Unloading System & Procedure Organic cooled transfer flask, transported by main station crane. Loading and unloading off-power from above core.
Irradiated Fuel Storage Spent fuel storage - 182 assemblies - fuel stored in organic filled cans - cans stored vertically in fixed configuration in water-filled storage bay.
Fuel storage block - 26 storage tubes - fuel can be stored in organic or dry - tubes immersed in water - designed for short-term storage.
Cannisters - as required (144-222 bundles per cannister) - fuel stored dry in seal-welded steel baskets within 0.75 m thick, reinforced concrete cannister.


Heat Transfer Area ~13,500 cm2 per fuel end (assuming radial heat transfer)
Heat Flux on the Fuel Element Surface Maximum 160 W/cm2
Average 75 W/cm2 (over length of fuel end)
Film Temperature Drop ~60oC
Maximum Design Fuel Temperature 1100oC
Maximum Design Clad Surface Temperature 500oC
Coolant Flow Area ~750 cm2
Channel Velocity of the Coolant 11.5 m/s - nominal velocity in average site
Coolant Mass Flow Rate 750 kg/sec.
Coolant Temperature & Pressures Temperature:
Inlet 280oC - 400oC
Outlet 320oC - 425oC

Inlet Header 315 psig (2.15 MPa)
Outlet Header 160 psig (1.1 MPa)
Provision for Shutdown Heat Removal Pressurizing pumps provide flow through standby coolers.


Heat Exchangers 3 circuits - 1 HX/circuit - sheel & tube
U-bend, single pass, water cooled tubes of seamless steel clad inside with 70/ 30 copper/nickel
Primary Coolant Losses & Decomposition Estimated damage rate at 30% high boiler ~4 kg/MWD.
Degassing and particulate removal systems operate on continuous basis. Insoluble gases are discharged to the atmosphere.
Safety Features of the Cooling System Pressure relief valves. Emergency injection tanks pressurized with nitrogen and containing 100,000 lb (45,000 kg) of coolant will release into the inlet header if pressure drops below 150 psig (1.1 MPa). Water can also be injected. Coolant pumps equipped with fly-wheels to give proper coast- down characteristic.
Provision for Detecting Fuel Element Defect Gross gamma scan on coolant outlet feeders.


Maximum Rate of Reactivity Addition 0.33 mk/sec
Trip Mechanism & Time Mechanism - moderator dump
Reactivity reduction 1 sec after trip signal: 13.8 mk
1.5 sec after trip signal: 25.7 mk
Sensitivity of Automatic Control 3 %
Temperature Coefficients Moderator: +0.14 mk/oC at 1 ppm B10 and 20oC
Coolant: -0.03 to +0.01 mk/oC
Fuel: -0.045 to -0.025 mk/% Rated Power
Burnable Poison Boron (93 wt% enriched in B10) in the form of Boric acid dissolved in the moderator
Other Control & Shutdown Provisions Control and regulation primarily by variation of moderator level. Boron-10 concentration in the moderator can be varied with injection pumps and ion exchange columns providing ~28 mk/ppm B10 of reactivity load


Form, Materials & Dimensions All welded vertical cylinder of ASTM A240 stainless steel, 16.5 ft (5 m) high, 8 ft 10 in. (2.7 m) I.D., tapered on top side with dished top and bottom.
Wall thickness 0.5 in. (1.27 cm)
Top head thickness 0.75 in. (1.91 cm)
Bottom head thickness 1.375 in. (3.49 cm)
Design and Working Pressures Design: 50 psig (3.52 kg/cm2)
Working: 8 psig (0.56 kg/cm2)


Reflector Heavy Water - 99.73%
Thickness - 17.64 in. (44.8 cm)
Radiation Level Outside Shielding [Design] less than 2 mr/hr in all unrestricted areas
Shielding Side: 5 in. (12.7 cm) steel + 6 in. (15.2 cm) water
7 ft. 6 in. 9229 cm) of 220#/ft (3.52 gm/cm3) concrete

Top: 22 in. (55.9 cm) steel + 22 in. (55.9 cm) water (shield)
18 in. (45.7 cm) steel + 3 in. (7.6 cm) masonite (deck plate)

Bottom: 22 in. (55.9 cm) steel + 22 in. (55.9 cm) water

Cooling: Water circulation

Max Temp: Side 116oC
Top 63oC
Bottom 52oC
Average Cooling Water Temp: 35oC
Reactor Overall Dimensions with Shielding Approx. 32 ft (9.75 m) high x 26.5 ft (8 m) diameter


Containment Type & Material Normal Industrial type building with absolute filter protection on ventilation effluent
Surroundings Locate adjacent to Whiteshell Provincial Park. Total population within 25 mile radius - less than 8,000.
Seismology - Zone 1 on Canada Earthquake Probablity Map - only slight damage has been recorded.
No single wind direction >25% frequency.


Special Any coolant channel can be isolated from the system and run as an experimental loop. Similarly, any pressure tube can be removed from the reactor and replaced by a tube of different design, provided only that it fits in the calandria tubes.
The coolant system is split into three circuits: thus three organic coolants can be tested simultaneously.
Experimental Loops Four experimental loops are installed, and there is room for two additional loops.
In-Core Irradiation Sites Three pneumatic capsule tubes transport samples for irradiation into an outer site in the core. One is connected directly to the Hot Cells, the other to the Radiochemistry Laboratory.
Special fuel hanger rods may be installed in any site in the reactor. Samples up to 1.75 in. (4.5 cm) in diameter can be irradiated in the centre of a fuel assembly.
Three experimental loops are fuelled with an assembly mounted on a large hollow hanger rod. Devices (e.g. creep machines, steam autoclaves, etc.) up to 2.8 in (7.1 cm) in diameter can be operated in a fast neutron flux (>1 MeV) of ~1014 n/cm2 sec.

Revised March 1982

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