NUCLEAR HEAT FOR HOMES

North Pickering, a new Canadian town east of Toronto, next to Ontario Hydro's nuclear plant, was chosen for an extensive study as yet theoretical of the economic feasibility of heating the homes of up to 80,000 people with surplus heat from the power plant, which will contain four 540 MW CANDU units. (CANDU is a Canadian-designed reactor, not used in the US, which uses heavy water as a moderator and runs on unenriched uranium ore.)

The study considered five alternative methods of heating, including conventional individual heating by fossils or electricib, and concluded that the long-term economic, conservation and environmental benefits of the-nuclear district heating appeared superior to individual heating, and to fossil district heating as well.

The system would consist of a closed hot water loop between the power plant and storage reservoirs in the town. The total length of the transmission lines would be 15 miles, and the hot water would flow at 58,000 gallons per minute, leaving the power plant at 280 degrees F and returning at 140 degrees F.

Now that kind of heat (for 80,000 people!) cannot be obtained as "waste" heat, the heat that is there anyway; it has to be produced by making the reactor run harder. However, if the heat is not there anyway, the capacity is there anyway, and the heat can be produced during eight hours off-peak nighttime operation and stored for use during the rest of the day in a neat peak-shaving arrangement.

The 24-hour heat supply would be stored as hot water in shallow excavations topped by a concrete roof supporting a surfaced car park, and the storage tanks would be stratified to ensure a minimum of mixing between the hot (280 degrees F) and cooler (140 degrees F) water. The system would satisfy about 50% of the daily demand in winter (the remainder would come from central fossil-fired stand-by boilers), and 90% of the year-round requirements.

The economics of the system appear fair to good. Capital costs would be high about $400 million over 15 years, computed to $70 million to install heating equipment in indiual buildings But the difference would be made up in some 12 years, for the savings in fuel costs would amount to $30 million a year - two million barrels of fuel oil. In addition, of course, there are the intangible benefits of e1iminated air pollution.

The inevitable cry of "Radioactivity in the home " will of course go up, and as usual, it will be pure piffle. The water is heated by steam in heat exchangers and never comes into contact with the nuclear power source.

Besides, there is plenty of radioactivity in the home already: TV sets, building materials, food, air, and humans. Among other sources: the radionuclides in heating oil.