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PRELIMINARY POWER FNR SPECIFICATION SHEET
This specification sheet summarizes the results of the FNR Design set out at www.xylenepower.com/FNR%20Design.htm
PURPOSE: Provide a modular power FNR that can supply thermal power of up to 940 MWt in 1.77 MWt increments. Modules to be factory assembled and truck/rail transportable. To the extent possible use existing readily available materials and technology.
RATED OUTPUT POWER: 1000 MWt (~ 333 MWe) at 15% linear fuel tube swelling
RATED FUEL BURNUP FRACTION / FUEL CYCLE: ~ 15%
FEATURES: Metallic U-Pt-Zr core rods, metallic U-Zr blanket rods, primary sodium natural circulation, intermediate sodium induction pump circulation, passive high temperature fission reaction shutdown, passive cold shutdown on loss of control power, two independent active shutdown systems, few moving parts, 532 active fuel bundles, gamma ray emission sensing for every active fuel bundle, control portion vertical position sensing for every active fuel bundle, independent control portion vertical position control for every active fuel bundle, floating steel liquid sodium pool cover for every fuel bundle, 32 independent secondary heat transport circuits for high heat removal reliability, reactor site sufficiently above local flood level for certain exclusion of flood water from sodium, dry cooling towers for minimum environmental impact.
MODULAR CONSTRUCTION: Reactor is field assembled by connecting together truck transportable modules. A fuel bundle inside its lead biosafety transportation container can be transported by a conventional 18 wheel trailer truck. The longest steel beams and pipe sections are less than 20 m in overall length. Some stainless steel field welding is required to achieve gas tight seals around the liquid sodium pool.
SITE: Must have igneous or shale bedrock base;
SITE: Local water table must always be below the bottom of the primary sodium pool;
SITE: Must have sufficient natural drainage to ensure no possibility of adverse water table rise or flood water backup;
SITE: Must be suitable for use of dry cooling towers;
PRIMARY COOLANT: Pure liquid sodium
SECONDARY COOLANT: Pure liquid sodium
TURBINE WORKING FLUID: Pure water
LIQUID SODIUM POOL INSIDE DIMENSIONS: 20 m diameter X 16.5 m deep
LIQUID SODIUM NOMINAL DEPTH: 15.5 m
PRIMARY LIQUID SODIUM VOLUME: 4867 m^3
PRIMARY SODIUM MASS: 4867 m^3 X 0.927 tonne / m^3 = 4512 tonnes
SECONDARY SODIUM VOLUME: ~ 200 m^3
TOTAL SODIUM REQUIREMENT: 4700 tonnes
REACTOR CORE ZONE HEIGHT: 0.35 m
REACTOR CORE ZONE DIAMETER: 11.2 m
REACTOR BLANKET THICKNESS: 1.2 m
REACTOR BLANKET HORIZONTAL OD: 13.6 m
LIQUID SODIUM NEUTRON ABSORPTION GUARD BAND: 2.8 m wide
LIQUID SODIUM POOL THERMAL INSULATION: Low density saw cut lava rock blocks, 3.0 m thick below primary sodium pool bottom and behind the primary sodium pool cylindrical wall
SAW CUT LAVA ROCK BLOCK REQUIREMENT:
Pi[((13 m)^2 X 19.5 m) - ((10 m)^2 X 16.5 m)
= Pi [3295.5 m^3 - 1650 m^3] = 5169.5 m^3
PRIMARY LIQUID SODIUM POOL SURFACE TEMPERATURE at 1000 MWt: 440 deg
PRIMARY LIQUID SODIUM POOL BOTTOM TEMPERATURE AT 1000 MWt: 340 deg C
PRIMARY LIQUID SODIUM CIRCULATION: Natural circulation
MAXIMUM PARASITIC HEAT LOSS VIA THERMAL CONDUCTION THROUGH LAVA ROCK: 0.3 MWt
LAVA ROCK CONDUCTED HEAT REMOVAL: Forced air through 1 m wide cooling channel
Air cooled surface area of primary liquid sodium outer wall:
Pi ((13 m)^2 + 13 m (19.5 m))
= Pi (13 m (32.5 m))
= 1327.3 m^2
OUTER POOL WALL SURFACE HEAT FLUX = 300,000 W / 1327.3 m^2
= 226.02 W / m^2
RATED FUEL TUBE WALL TEMPERATURE DROP: 15 C
FUEL TUBE INITIAL DIMENSIONS: 0.500 inch OD, 0.37 inch ID , 6.0 m long
FUEL TUBE DIMENSIONS AT MAXIMUM PERMITTED 15% LINEAR SWELLING: 0.575 inch OD, 0.4255 inch ID
FUEL TUBE GRID: square, 0.625 inch center to center
FUEL TUBE INITIAL MATERIAL: HT-9 (85% Fe + 12% Cr), Mn < 1.5%, C = 0, Ni = 0
FUEL TUBE MATERIAL AT END OF TUBE LIFE: 60% Fe, 24% Cr, 16% Ti
FUEL BUNDLE: fuel tubes + surround bottom grating + outer shroud + 2 inner shrouds + 4 outer corner girders + 4 inner corner girders + 8 slide giude girders + control portion bottom grating + indicator tube + indicator tube diagonals + bottom plate + piston push rod
ACTIVE FUEL BUNDLE WEIGHT: ~ 3.6 tonnes
NUMBER OF ACTIVE FUEL BUNDLES: 640
NUMBER OF FUEL BUNDLE CONTROL PORTION ACTUATORS: 640
NUMBER OF PASSIVE FUEL BUNDLES: 296
NUMBER of FUEL TUBES PER ACTIVE FUEL BUNDLE CONTROL PORTION: 244
NUMBER of FUEL TUBES PER ACTIVE FUEL BUNDLE SURROUND PORTION: 232
TOTAL NUMBER OF FUEL TUBES PER ACTIVE FUEL BUNDLE: 476
NUMBER OF FUEL TUBES PER PASSIVE FUEL BUNDLE: 556
CORE ROD ALLOY AT START OF FUEL CYCLE: 70% U-238, 20% Pu, 10% Zr
CORE ROD ALLOY AT END OF FUEL CYCLE: 65% U-238, 10% Pu, 10% Zr, 15% fission products
CORE FUEL BURN-UP: 15% / fuel cycle
INITIAL CORE ROD OD: 8.08 mm_____
INITIAL CORE ROD DENSITY:_______
INITIAL CORE ROD LENGTH: 0.35 m_____
NUMBER OF CORE RODS: 476 fuel tubes / active bundle X 640 active bundles X 1 core rod / fuel tube = 304,640 core rods
TOTAL CORE ROD WEIGHT: ~ 80 tonnes_______
TOTAL Pu REQUIREMENT: ~ 16 tonnes_________
INITIAL BLANKET ROD ALLOY: 90% U, 10% Zr
BLANKET ROD DENSITY: _________
BLANKET ROD OD: 8.5 mm
BLANKET ROD LENGTH: 0.60 m
NUMBER OF BLANKET RODS: (4 blanket rods / active fuel tube X 476 active fuel tubes / bundle x 640 active bundles)
+ (5 blanket rods / passive fuel tube X 556 passive fuel tubes / passive bundle X 296 passive bundles)
= 1,218,560 + 822,880
= 2,041,440 blanket rods
TOTAL BLANKET ROD WEIGHT: _______
INTERMEDIATE HEAT EXCHANGER WALL TEMPERATURE DROP: 10 C
INTERMEDIATE HEAT EXCHANGE TUBE DIAMETER: 0.500 OD, 0.37 inch ID
INTERMEDIATE HEAT EXCHANGE TUBE LENGTH: 6.0 m
INTERMEDIATE HEAT EXCHANGE TUBE GRID: square, 0.75 inch
INTERMEDIATE HEAT EXCHANGE TUBE MATERIAL: Inconel 600
INTERMEDIATE HEAT EXCHANGE TUBE BUNDLE: 16 X 103 = 1648 tubes
INTERMEDIATE HEAT EXCHANGE TUBE BUNDLE MANIFOLD LENGTH: 2.2 m
INTERMEDIATE HEAT EXCHANGE TUBE BUNDLE MANIFOLD WIDTH: Tapered 1.4 m to 1.8 m
NUMBER OF INTERMEDIATE HEAT EXCHANGE BUNDLES: 32
NOMINAL THERMAL FLUX THROUGH EACH HEAT EXCHANGE BUNDLE: 1000 MW / 32 = 31.25 MWt
THERE ARE 32 TURBOGENERATORS EACH WITH AN OUTPUT OF ABOUT 11 MWe
INTERMEDIATE HEAT EXCHANGE DESIGN: baffled, counter flow, single pass
INTERMEDIATE HEAT EXCHANGE SODIUM FLOW: 32 X 0 to 0.25 m^3 / s
FULL LOAD INTERMEDIATE SODIUM FLOW: 8.56 m^3 / s
INTERMEDIATE HEAT EXCHANGE BUNDLE EXTERNAL PIPING: 16.0 inch OD, 12.8 inch ID
INTERMEDIATE HEAT EXCHANGE BUNDLE INTERNAL WORKING PRESSURE: 11.5 MPa (vent argon at 12 MPa, test to 18 MPa, SMYS at 36 MPa)
REACTOR THERMAL POWER CONTROL: Variable speed secondary liquid sodium pumps control the secondary liquid sodium flow rate through the intermediate heat exchange bundles. At low pump speeds the heat extraction rate is low. At high pump speeds the heat extraction rate is high. The secondary liquid sodium return temperature to the intermediate heat exchange bundle is ~ 320 C to 330 C due to the action of the steam generator PRV. The steam generator must tolerate a wide range of liquid sodium flows.
SECONDARY SODIUM LOOP HIGH TEMPERATURE AT FULL LOAD: 430 C
SECONDARY SODIUM LOOP LOW TEMPERATURE AT FULL LOAD: 330 C
SECONDARY SODIUM LOOP TEMPERATURE DIFFERENTIAL AT FULL LOAD: 100 deg C
STEAM GENERATOR TUBE WALL TEMPERATURE DROP AT FULL LOAD: 10 C
WATER TEMPERATURE IN STEAM GENERATOR: ~ 320 C (608 F)
SATURATED STEAM WORKING PRESSURE IN STEAM GENERATOR: = 11.25 MPa
SECONDARY SODIUM NORMAL WORKING PRESSURE: 11.5 MPa
MAXIMUM ALLOWABLE TRANSIENT STEAM WORKING PRESSURE: 12 MPa
MAXIMUM TRANSIENT INTERMEDIATE SODIUM WORKING PRESSURE: 12 MPa
SECONDARY SODIUM LOOP CIRCULATION PUMPS: 32 X Electric induction (No moving parts), 0.0 - 0.30 m^3 / s . These pumps control the rate at which heat is extracted from the reactor and hence indirectly control the reactor thermal power.
SECONDARY SODIUM PIPE FLOW VELOCITY: 0 to 3.61 m / s
SECONDARY SODIUM LOOP PRESSURE CONTROL: Argon injection into each secondary loop expansion tank tracks the steam pressure in the corresponding steam generator
DRY STEAM TEMPERATURE AT NO LOAD: 440 C
DRY STEAM TEMPERATURE AT FULL LOAD: 420 C
SATURATED STEAM TEMPERATURE: 320 C
FNR START FUEL AVAILABILITY FROM EXISTING CANDU SPENT FUEL: Sufficient for 12 X 1000 MWt FNRs
MATERIAL CONSTRAINT: Fuel tube linear diameter swelling should be kept to less than 15% to maintain the specified reactor output power and fuel bundle safety margin. In this respect use of HT-9 or similar Fe-Cr fuel tube material with low Ni and low C is recommended.
INDIVIDUAL FUEL BUNDLE DISCHARGE TEMPERATURE MONITORING: Uses fuel bundle control portion positioning to keep all fuel bundle primary sodium discharge temperatures the same irrespective of uneven fuel bundle reactivity and uneven fuel tube swelling. As a fuel bundle ages its thermal output power will gradually decrease due to reduced primary liquid sodium flow.
THREE INDEPENDENT FISSION SHUTDOWN MECHANISMS: active fuel bundle red group control portion withdrawal, active fuel bundle black group control portion withdrawal, fission shutdown via liquid sodium thermal expansion;
MELTDOWN PREVENTION: primary sodium floor cover configured to prevent critical mass formation fuel melting occurs;
The FNR design parameters have been set out in sufficient detail on this web site that a team of competent engineering technologists should be able to proceed with initial CAD drawings.
An important issue is automation of the fuel rod, fuel tube and fuel bundle fabrication and fuel recycling steps as they repeat hundreds of thousands of times per reactor.
The next step is to meet with persons who have hands on experience with high volume 0.5 inch Fe - Cr steel tube production, welding and quality control to identify the provisions that must be made for automated fuel tube and fuel bundle assembly and testing.
3) The reactor fabrication is dominated by proper alloy mixes and automated: fuel rod and fuel tube production, quality control, and testing issues. Each FNR has:
609,280 + 329,152 = 938,432
gas tight fuel tube end plug welds. This welding must be highly automated. The economics of FNRs is entirely dependent on this manufacturing automation.
4) Each secondary sodium loop is independent and operates at a high pressure. This pressure is controlled by injection of argon into each secondary loop's expansion tank.
5) FNRs provide the only route to sustainable displacement of fossil fuels.
6) A major near term Ontario political consideration is future FNR siting and related transmission planning.
7) The safety issues are quite different from a water cooled reactor.
8) Moving this project forward likely requires an alliance between an existing 0.500 inch OD steel tube producer, an existing tube type heat exchanger producer and an existing producer of automated tube welding equipment. To be economic the automated weld rejection rate must be very low. Achieving that yield will require good control of the heat exchange manifold casting quality.
8) There are 640 active fuel bundles, each with 476 fuel tubes, of which 244 tubes form the control portion. The active fuel bundle control portions must be positioned to keep each fuel tube bundle's discharge temperature at 440 C. It is important that the control portion positioning systems be independent of each other so that adjacent bundle control system failures are extremely rare.
9) The FNR design must safely tolerate intentional acts of sabotage intended to cause fuel melting or prompt neutron criticality. If fuel melting does occur it must not lead to a critical mass accumulating on the primary liquid sodium pool floor.
10) From a safety perspective this power FNR is a collection of 640 X 1.6 MWt reactors inside a common enclosure. The system must be fault tolerant. For safety a fault in one fuel bundle must not prevent safe shutdown of adjacent fuel bundles. Shutdown of the 8 nearest neighbor fuel bundles should make a faulty fuel bundle sub-critical regardless of its control portion position.
11) From a financial perspective the maximum value of one 250 MWe FNR is:
$2 billion in spent CANDU fuel disposal cost savings plus (250,000 kW X $10,000/ kW)
= $2 billion + $2.5 billion
= $4.5 billion
A FNR will likely be a reasonable financial investment provided that the assembly automation issues are resolved with certainty.
This web page last updated April 17, 2018
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