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Nuclear Monitor Issue: 

(August 22, 2003) While the Nuclear Energy Institute, the industry lobby group, continues to tout nuclear power as environmental friendly, the once-through cooling system used by the majority of U.S. NPPs has again come under increased criticism by two different state authorities.

(591.5536) NIRS - Both the New York State Department of Environmental Conservation and the California Regional Water Quality Control Board Central Coastal Region criticized the use of coastal and river water to cool nuclear power stations. State authorities concluded that the routine operation of nuclear power stations is killing billions of fish and destroying marine and aquatic habitats by sucking in tremendous amounts of water each day and spewing it out as hot water.

Nuclear power stations like Entergy's Indian Point on the Hudson River in New York and Pacific Gas & Electric's Diablo Canyon on the central coast of California take in over 2.5 billion gallons (9.5 million cubic meters) of water each day per site in order to quench the generated steam used to spin turbines for electricity production.

In a once-through cooling system, river water is used to quench the steam in the turbine circuit and afterwards released directly into the river again. The alternative to once-through cooling is the use of cooling towers. The water circulating in a cooling tower is being quenched by outside air, requiring less river water and resulting in less releases of hot water. However, large cooling towers increase the visual impact of an NPP and "spoil" the nuclear industry's wish to be "emission-free".

A study performed by the New York Department of Environmental Conservation and publicly released on 11 July 2003 looked not only at Entergy's two reactors at Indian Point, representing the Hudson River's number one largest thermal polluter, but also the river's sixth and the seventh largest fossil fueled units using once-through cooling systems.

The electrical power facilities combined take in 1.69 trillion gallons (6.4 billion cubic meters) of water annually, more than three times the water used each year by New York City's 9 million residents and two neighboring counties. The study found that the greatest harm came from billions of fish and larvae being sucked in (entrained) into the station cooling condensers and killed upon discharge to the river with the heated water (up to 35° Fahrenheit (19° Celsius) hotter than the intake water temperature).

The state study further concluded that there was greater harm from the heated water being discharged back into the Hudson's tidal estuary than previously assumed. The three electrical generating facilities' combined thermal discharge, 220 trillion BTUs per year (232 million GigaJoules), is the equivalent amount of heat generated by the detonation of a Hiroshima-size nuclear bomb approximately every two hours (1). As a result entire species of fish and vegetation are disappearing from larger reaches of the river, victims of the hot water discharge.

On 10 July 2003, the California Regional Water Quality Control Board for the Central Coast regarded the same destruction to the coastal marine environment of Diablo Cove from the two 1000 MW units of the Diablo Canyon nuclear station. The coastal water commission withdrew its support from an earlier proposed settlement which would have required PG&E to conserve 2000 acres of land north of the reactor and pay out US$4 million toward marine restoration projects, including abalone breeding and repopulation of coastal waters.

In the end, the water board rejected the proposal after environmental groups, including Earth Corp, Mothers For Peace, and NIRS, along with a state team of marine biologists criticized that the settlement would not offset the ongoing marine damage from the continued operation of the cooling system. The coastline thermal impact zone was found to be larger than predicted. Field's Cove, intended as a coastline control zone for studying the station's discharge impact on Diablo Cove, is periodically thermally polluted by the reactors nearly two miles away.

The actual discharge impacts include major reductions of fish species and habitat, including the almost complete loss of some marine species and major increases of "bare rock" in Diablo Cove. The state authority and PG&E now must go back to the drawing board for a solution which could include a state issued Cease and Desist Order on the operation of Diablo Canyon.

In both cases, under the Clean Water Act, state authorities could order the nuclear power stations to cease using river and coastal water as their primary source to cool the reactors and switch to cooling towers. Such enforcement is highly unlikely without the presence of significantly more public pressure. While cooling towers use an order of magnitude less water resources (30 million gallons per day) nuclear power companies vehemently argue that their construction and reduced cooling efficiency is economically prohibitive.

Such financially-driven opposition through "cost/benefit analyses" has repeatedly blocked environmental efforts to upgrade stations that rely upon the wasteful and harmful system. However, the growing destruction of the marine and aquatic environment is potentially irreversible if the operation of once-through cooling is allowed to continue unchecked. More reason to call for the abolition of nuclear power, altogether.

In February 2001, NIRS and the Safe Energy Communication Council published the report Licensed to Kill: how the nuclear power industry destroys endangered marine wildlife and ocean habitat to save money (see WISE/NIRS Nuclear Monitor 544.5252: "Cooling water systems kill marine wildlife"). The report describes the devastating consequences of hot water releases to marine wildlife (2).

(1) This is a surprising amount of heat coming from electricity generating plants (primarily nuclear) just being dumped into the river, lake or ocean. The figure appears in the 11 July 2003 issue of the Journal News in an article authored by Roger Witherspoon. He extrapolated the Hiroshima equivalent (80 billion BTUs) from the original figure in the NY study--- 220 trillion (!) BTUs/year for combined release from the Indian Point nuclear station and the fossil units at Roseton and Bowline, NY.
(2) The summary of Licensed to Kill and other related documents can be found at:

Contact: Paul Gunter at NIRS (

In several countries in Europe, temperatures during the first weeks of August reached exceptional historical levels. In a long lasting period, temperatures were between 30 and 40 degrees Celsius (85-105 degrees Fahrenheit). As a consequence, river water temperatures increased and in combination with little rainfall the effect was even worse. Several countries decided to restrict releases of cooling water from power stations to prevent extreme environmental damage (fish killing), but exceptions were soon made for NPPs.

As a consequence, several NPPs in Germany, France, Belgium and Switzerland faced problems and would have to reduce power output significantly. Nevertheless, France's environment minister relaxed the cooling outlet temperature of 7 sites (24 reactors) until the end of September to allow continued operation. The allowed temperatures of cooling water is one degree higher for most of these reactors, but three degrees for the reactors at Tricastin and three other sites. The four reactors at Tricastin however are not necessary for public electricity production but is used as power supplier to the Eurodif uranium enrichment plant. In Belgium, Doel NPP (4 reactors) got permission for discharges at 33 degrees Celsius and German NPPs have been allowed a two degrees increment. Switzerland temporarily reduced power output at its NPPs.

The exceptions for the French and German NPPs have caused criticism of environmental groups in both countries. They are afraid that the hot water discharges will cause significant damage to nature and environment.
WNA Weekly Digest, 15 August 2003; Press Agency ANP (NL), 12 August 2003