Darlington NPP Design Data
The table below provide design data for Darlington NPP.
| Location | Town of Newcastle, Ontario |
| Owner, operator | Ontario Hydro |
| Designers | Ontario Hydro |
| Number of units | Four |
| Rated output per unit | Generator output 935 MW(e) |
| Self-consumption 54 MW(e) | |
| Net electrical 881 MW(e) | |
| Overall net efficiency | 31.70% |
| Fuel | Natural Uranium Dioxide (UO2 |
| Moderator | Deuterium Oxide (D2O-heavy water) |
| Coolant | Pressurized heavy water |
| Type | Horizontal pressure tube |
| Construction | Start of construction late 1977 |
| Schedule | In-service dates: |
| Unit 1-1990 Unit 3-1991 | |
| Unit 2-1990 Unit 4-1992 | |
| Building and Structures | |
| Powerhouse | |
| Overall length | 563 6 m (1899.3 ft.) |
| Overall width | 137.0 m (461.7ft.) |
| Reactor building | |
| Form | Rectangular |
| Material | Reinforced concrete |
| Length | 49.8 m (163.4 ft.) |
| Width | 28.6 m (93.8 ft.) |
| Height | 51.1m (167.7ft.) |
| Design pressure | -53.1 kPa(g) to + 96.5 kPa(g) |
| (-7.7 psi(g) to + 14.0 psi(g)) | |
| Reactor auxiliary bay | |
| Form | Rectangular, 5 story, steel frame, concrete floor & 2 story concrete basement. |
| Length | 91.2 m (299.2 ft.) |
| Width | 50.65 m (166.2 ft.) |
| Height | 58.2 m (190.9 ft.) |
| Turbine hall | |
| Form | Rectangular, steel frame, concrete and grating floor. |
| Length | 91.2 m (299.2 ft.) |
| Width | 54.8 m (180.0 ft.) |
| Height | 44.9 m (147.0 ft.) |
| Turbine auxiliary bay | |
| Form | Rectangular, steel frame, concrete and grating floors and basement |
| Length | 91.2 m (299.2 ft.) |
| Width | 18.8 m (61.7 ft.) |
| Height | 45.9 m (150.0 ft.) |
| Central service area | |
| Form | Rectangular, steel frame, concrete floors. |
| Length | 63.0 m (206.7 ft.) |
| Width | 136.5 m (447.8 ft.) |
| Height | 45.9 m (150.0 ft.) |
| Vacuum structure | |
| Form | Cylindrical prestressed concrete |
| Diameter | 50.4m (170.0 ft.) |
| Height | 71.2 m (239.9 ft.) |
| Free volume | 95 000 m3 (3.35 x 105 ft.3) |
| Design Pressure | -101.4 kPa(g) to + 96.5 kPa(g) |
| (-14.7psi(g) to + 14.0 psi(g)) | |
| Water storage | 11500 m3 (4.06 x 105 ft.3) |
| Fuelling facilities auxiliary building | |
| Form | Rectangular, concrete floors & walls below grade, steel frame with concrete floors above grade. |
| Location | One at either end of the powerhouse. |
| Length | 66.7 m (218.83 ft.) |
| Width | 54.0m (177.16 ft.) |
| Height | 22.85 m (74.92 ft.) |
| Reactor vessels | |
| Calandria shell | |
| Form | Horizontal, stepped cylinder comprising of main shell, two sub-shells & two annulus plates. |
| Material | Austenitic stainless steel |
| Inside diameter | 8 458 mm (27.75 ft. ) |
| Main shell thickness | 31.75 mm (1.25 in.) |
| Length | 5981 mm (19.50 ft.) |
| Calandria end shields | |
| Purpose | Integral with calandria shell, provides support for alignment of fuel channels & shutdown shielding of the reactor faces. |
| Material | Austenitic stainless steel (filled with steelballs & light water 60:40 by volume) |
| Weight (filled) | 2 370 Mg (5,241,000 lb.) |
| Length (each) | 1 016 mm (3.33 ft.) |
| Calandria tubes | |
| Quantity | 480 |
| Material | Zircaloy-2, seamwelded |
| Inside diameter | 129 mm (5.077 in.) |
| Wall thickness | 1.37 mm (0.054 in.) |
| Reactor Core | |
| Pressure tubes | |
| Purpose | Fuel channels & primary heat transport |
| Quantity | 480 tubes (24 x 24 array) |
| Material | Zirconium-Niobium alloy |
| Inside diameter | 103.4 mm (4.07 in.) |
| Wall thickness | 4.2 mm (0.16 in.) |
| Lattice Pitch | 285.8 mm (11.25 in.) |
| Core Radius | 3 532 mm (139.06 in.) |
| Core Length | 5 944 mm (234.0 in.) |
| Average reflector thickness | 700 mm (27.6 in.) at midpoint |
| Fuel load | 6 240 bundles (108 Mg U) (237,600 lb. U) |
| Moderator and Reflector D2O | 312 Mg D2O (686,400 lb. D2O) |
| Maximum channel power | 6.4 MW |
| Average burn-up | |
| Reactor control | 164 MW.h per kg. U |
| Reactivity control Units | 2 digital computers per unit |
| Shutdown systems - shut-off rods | |
| Purpose | Safety devices to quickly terminate reactor operation |
| Quantity | 32 rods |
| Type | Stainless steel - cadmium - stainless steel sandwich in the form of a tube |
| Orientation | Vertical through lattice |
| Reactivity worth | -49 mk within 2.0 sec. |
| Drive mechanism | Winch & cable driven via an electro magnetic friction clutch by a constant speed induction motor |
| Shutdown system - liquid injection | |
| Purpose | Safety system to terminate reactor operation |
| Type | Gadolinium nitrate solution |
| Reactivity worth | -55 mk |
| Injection method | Pressurized helium to drive solution into bulk moderator through nozzles |
| Control system - liquid zone control units | |
| Purpose | Suppress unwanted changes in neutron flux distribution |
| Quantity | 14 separate zones |
| Type | Natural water compartments |
| Orientation | Vertical |
| Reactivity rate of Change | - 0.1 mk per sec. |
| Reactivity worth | 6.3 mk (full to empty) |
| Control system - control absorber rods | |
| Purpose | Inserted if reactivity rate of change of Liquid Zone Control system is inadequate |
| Quantity | 4 rods |
| Type | Same as Shut-off Rods |
| Reactivity rate of change | + 0.1 mk per sec. |
| Reactivity worth | -9 mk (inserted) |
| Control system - adjuster rods | |
| Purpose | Normally inserted to limit fuel power; can be withdrawn to provide increased reactivity |
| Quantity | 24 rods |
| Type | Stainless steel |
| Reactivity rate of change | 0.04 mk per sec. |
| Reactivity worth | + 17 mk |
| Moderator | |
| Type | Heavy water |
| Total volume | 312.0 m3 (11,019.5 ft.3) |
| Purity | 99.95% D2O by weight |
| Heat load (max. design) | 138.0 MW (th) |
| Primary coolant | |
| Type | Pressurized heavy water |
| Quantity | 25.2 kg/s (199,210 lb./hr) |
| Flow per channel (max.) | 280 Mg (617,290 lb.) at 37.80C (1000F) |
| Reactor inlet Coolant temperature | 267 degrees C (513 degrees F) |
| Reactor outlet temperature | 310 degrees C (590 degrees F) |
| Reactor outlet header Pressure | 10.0 MPa(a) (1 450 psia) |
| No. of pumps | 4 per unit |
| Steam generators | |
| Quantity | 4 per unit |
| Steam pressure at drum (design) | 5.068 MPa(a) 735 psia) |
| Steam temp. at drum | 264.75 degrees C (508.5 degrees F) |
| Total steam output | 1 310.4kg/s (10.33 x 106 lb./hr) |
| Feedwater inlet temperature | 176.7 degrees C (350 degrees F) |
| Fuel elements | |
| Type | 37 element bundles, 495 mm (19.5 in.) long |
| No. per channel | 13 bundles |
| Diameter of bundle | 102.49 mm (4.05 in.) |
| Weight of U02 per bundle | 21.23 kg (46.71 lb.) |
| Total weight of bundle | 23.5 kg (51.7 lb.) |
| Maximum bundle power | 787 kW (time averaged) |
| Turbine generator | |
| Turbine | One tandem compound unit per with external moisture separation steam reheat (2 stages) |
| No. of high-pressure cylinders | 1 double flow |
| No. of low pressure cylinders | 3 double flow |
| Speed | 1 800 RPM |
| Throttle steam pressure | 4.83 MPa(g) (700 psig) |
| Type of condenser | Two pass |
| Cooling water flow | 31.6 m3/sec. (417,392 gpm) |
| Generator | One per turbine |
| Rating (85% power factor) | 1101 MVA |
| Terminal voltage | 22 kV |
| Frequency | 60 Hz |
| Transformers | |
| Main output | 12-330,000 kVA, 1 phase, 60 Hz, 21.45/525 kV (3 per unit) |
| Unit service | 4-80,000 kVA, 3 phase, 60 Hz, 22113.8/13.8 kV |
| System service | 4-80,000 kVA, 3 phase, 60 Hz, 500/13.8/13.8 kV |
| Circuit breakers | |
| 500 kV | 18 - 2 cycle, 4000 A, 100 kA, SF breakers |
| 13.8 kV | 154 - 750 MVA, 1200 A and 2000 A |
| 4.16 kV | 298 - 250 MVA, 1200 A and 2000 A |
| Standby power | |
| Combustion turbines | 4 - 26 MW, 13.8 kV |
| Emergency power generators | 2 - 6.8 MW, 4.16 kV |
| Acknowledgement | Information on this page graciously provided by Ontario Hydro. |
Copyright © 1996-2004. Joseph Gonyeau, P.E.. The Virtual Nuclear Tourist. All rights reserved. Revised: December 6, 2001.