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Nuclear lobbyists celebrate Union of Concerned Scientists' 'backflip' on nuclear power

Nuclear Monitor Issue: 
Jim Green ‒ Nuclear Monitor editor

Nuclear power advocates are celebrating the Union of Concerned Scientists' (UCS) new pro-nuclear position … although the organization has not changed its position and is not pro-nuclear (or anti-nuclear).

A recent UCS report found that 22% of nuclear power capacity in the US is unprofitable or will soon become unprofitable and that greenhouse emissions will rise to the extent that nuclear is replaced by fossil fuels.1 It thus offers support for broad policies that would in effect subsidize the ongoing operation of some nuclear plants as well as supporting other low-carbon technologies and policies. Support for nuclear subsidies is conditional on consumer protection, safety and security requirements, and investments in renewables and energy efficiency. On average, it would cost US$814 million annually to bring unprofitable plants back to a breakeven point according to the UCS report.

So, should unprofitable nuclear power plants be subsidized if they meet the UCS's criteria? Dr Gregory Jaczko, chair of the US Nuclear Regulatory Commission from 2009‒2012, doesn't think so. In a media statement, Jaczko said: "The Union of Concerned Scientist models don't reflect the reality of the United States electricity market. Renewables are getting cheaper faster than expected and are in some cases the least expensive source of electricity. In contrast, nuclear has only gotten more expensive. New nuclear is a financial boondoggle: the four new plants licensed while I chaired the Nuclear Regulatory Commission are costing billions more than projected, and two of them have been canceled after spending $10 billion. Imagine how much carbon-free generation could have been deployed with that investment. Employing nuclear for climate change is like Dorothy seeking the Wizard of Oz to get home. It's an expensive enticing mirage."2

In any case, the substantive issues have been lost in a blizzard of fake news about the UCS allegedly shifting its position on nuclear power. Steve Clemmer from the UCS said "we are getting a bit more vocal" about the benefits of keeping nuclear plants open.3 That's as far as it goes ‒ hardly a backflip and hardly momentous. Moreover, the UCS's support for keeping reactors online is highly conditional.

Nuclear advocate Mark Lynas congratulated the UCS for having "broken with the anti-nuclear ideology that has been part of the advocacy group's DNA since the 1960s" and said the organization "deserves great credit for having the courage to take this step."4 The Third Way pro-nuclear group said that: "Coming from an environmental NGO as respected and intellectually rigorous as UCS, this report is a big deal."5

The Breakthrough Institute argued that "opposition to nuclear energy from the institutional environmental movement has been monolithic, so this marks a decided change in the nuclear landscape".6 And the Breakthrough Institute piece, titled 'The dam has broken', suggests that other groups might follow the UCS's lead: "this sort of thing often happens slowly, even imperceptibly, and then all at once".6

Ted Nordhaus from the Breakthrough Institute said: "UCS is the first major environmental NGO to recognize that nuclear energy presently, and for the foreseeable future, is a key climate mitigation technology."7 (As we recently noted in Nuclear Monitor, the Intergovernmental Panel on Climate Change envisages nuclear power being a marginal climate mitigation technology, dwarfed by renewables.8) The UCS report is "particularly symbolic" and it marks a "remarkable shift", Norhaus argues. He says it is likely but "by no means guaranteed" that other major environmental groups will follow the UCS's lead on the issue.7

A Boston Globe editorial argued that the UCS report is "symbolically, a really big deal" as the group's name is "practically synonymous with skepticism toward nuclear energy", and it is "hard to imagine a group with stronger historic anti-nuclear bona fides than the Union of Concerned Scientists".9

In fact …

But in fact, the UCS has never been anti-nuclear ‒ or pro-nuclear ‒ and it hasn't changed its position. Alan Nogee, who worked at the UCS for 17 years, 12 of them as Clean Energy Program Director, noted in the aftermath of the release of the UCS report that:

  • UCS has never called for a general closure or moratorium on nukes.10
  • UCS left the Safe Energy Communication Council following the Chernobyl disaster, when the Council voted to endorse a moratorium on new nuclear power.11
  • UCS has rejected numerous requests to endorse shutdowns.12
  • UCS has "worked to close or keep-closed-until-fixed, a handful of plants with specific safety and/or economic problems. It has rejected MANY requests from state & local groups to help close other plants or to support no-nukes laws."13
  • The UCS always distinguished between the positive economics / climate impact of continuing to operate existing reactor versus the negative economics of new build, and the need to hedge against uncertainties as to the capabilities of energy efficiency and renewables.14

Alex Frank from the Hastings Group said of the UCS report: "In fact, UCS did not change its views on nuclear power. It did not support new nuclear construction. It did not support subsidies for any specific existing reactor. It did not conclude that every existing nuclear plant should stay open. It did not state that retired nuclear plants will all be replaced with fossil fuels. It did not urge scaling back support for renewable energy to allow for more support of nuclear. It did not minimize concerns about nuclear power safety or the lack of effective watchdog review by the Nuclear Regulatory Commission."

In an article titled 'Seven Things People Got Wrong with UCS' 'Nuclear Power Dilemma' Report, Clemmer said: "[D]espite reporting to the contrary, UCS has not changed its position on nuclear power. Has UCS advocated vigorously for policies to increase the deployment of renewable energy to address climate change? Absolutely. Have we been a longstanding watchdog for nuclear power safety? You bet. Do we now believe the Nuclear Regulatory Commission (NRC) is an effective watchdog or that nuclear power safety concerns are overblown? Emphatically no. But UCS has long recognized that the current nuclear fleet is a significant source of low-carbon power and that nuclear plants should not retire precipitously without carbon-free replacements."15

Clemmer said "some of the media coverage and statements by the nuclear industry and other groups have mischaracterized our report and our past work". The seven points he makes to correct the record are as follows:15

1. The report does not promote new nuclear power plant construction.

While new nuclear plants could be built under a national carbon price or low-carbon electricity standard, our modeling shows they are too expensive compared to new wind and solar projects, energy efficiency programs, and natural gas plants with carbon capture and storage.

This isn't the first time UCS has shined a spotlight on the high costs of building new nuclear reactors. This 2016 UCS power sector deep decarbonization study found that nearly all nuclear and coal plants in the United States would be replaced by low-carbon technologies by 2050 under every scenario, except our "optimistic nuclear case."16

2. The report does not advocate for subsidies for any specific nuclear plants.

As explained by UCS President Ken Kimmell in his recent blog, "the report does not argue for subsidies to any specific plants. That case will have to be made in state-specific forums. Should states decide to support nuclear power plant subsidies, our report calls for them to be temporary and subject to periodic reassessment. Companies seeking subsidies must open their books and allow the public and regulators to make sure that the subsidies are needed and cost-effective, and that the same level of carbon free power cannot be provided during the relevant time period with less costly options."17 Any subsidies also must be part of a broader strategy to reduce carbon emissions that increases investments in renewables and efficiency.

3. Existing nuclear plants must also meet strong safety standards to be eligible for support.

Since the 1970s, UCS has been a leading nuclear safety watchdog. The new UCS report recommends that nuclear reactors must meet or exceed the highest safety standards under Nuclear Regulatory Commission's (NRC) Reactor Oversight Process to be eligible for any policy or financial support. If the NRC weakens these standards, as proposed by the nuclear industry, UCS could no longer support this recommendation. At the same time, UCS will continue to push for better enforcement of existing regulations, the expedited transfer of nuclear waste from overcrowded cooling pools to safer dry cask storage, strengthened reactor security requirements, and higher safety standards for new plants. We also consider the NRC safety standards to be a floor, not a ceiling. States could encourage plant owners to make other safety improvements that go beyond current NRC standards.

4. Not every currently operating nuclear plant should stay open.

The report highlights examples where it might make sense to shut down existing nuclear plants that are saddled with major, reoccurring safety issues such as the Pilgrim plant in Massachusetts that Entergy is closing next year and the Davis-Besse plant in Ohio that FirstEnergy is threatening to close in 2020 if it doesn't receive subsidies. Other examples include Indian Point, due to its proximity to New York City, and Diablo Canyon, which is located near earthquake fault lines in California.

It also might make sense to shut down plants with high operating costs or ones that need to make major new capital investments to continue operating safely. Examples cited in the report include Crystal River in Florida and San Onofre in California, which were retired in 2013 following failed steam generator replacements.

5. Not every nuclear plant that retires early will be replaced with fossil fuels.

The report acknowledges that with sufficient planning and strong climate and clean energy policies, some existing nuclear plants can be replaced with renewables, energy efficiency, or other low- carbon technologies. For example, California passed legislation in September that commits the state to replace Diablo Canyon with zero-carbon energy sources by 2025. And states experiencing rapid wind and solar power deployment such as Iowa, Nebraska, Kansas, and Texas could potentially replace their nuclear plants with low-carbon energy sources over a reasonable period of time. However, a significant portion of the electricity in most of those states is still generated by coal and natural gas. Replacing those fuels with renewables and efficiency would result in much greater emissions reductions than replacing nuclear plants, another low-carbon source of electricity.

6. UCS has long supported keeping existing nuclear reactors that meet high safety standards operating to combat climate change.

7. UCS has long supported a low carbon electricity standard (LCES), but not at the expense of renewable electricity standards (RES).

Renewable standards have been effective at reducing emissions, driving down the cost of wind and solar, and creating jobs and other economic benefits for states and in rural communities. They have also been affordable for consumers. Including existing nuclear power plants in state renewable standards could significantly undermine the development of new renewables and all the benefits that go along with them.

We recommend including existing nuclear in a separate tier of an LCES, as New York state has done, to limit costs to ratepayers and avoid market-power issues due to limited competition among a small number of large plants and owners.

A long history of fake nuclear news

The portrayal ‒ by some in the media and some nuclear lobbyists ‒ of the UCS report as a pro-nuclear turn is false and it is wishful thinking. Such misrepresentation is common enough. Here are some examples:

  • In 2016, the Wall Street Journal said the Sierra Club was debating its position on nuclear power. Michael Brune, Executive Director of the Sierra Club, said the organization "remains in firm opposition to dangerous nuclear power" and that the media article "reflects wishful thinking on the part of the nuclear industry"18
  • The Wall Street Journal claimed that the Natural Resources Defense Council (NRDC) was working to keep two aging reactors online in Illinois. Henry Henderson from the NRDC said the newspaper was "dead wrong on our goals, focus and motivation" and that the organization's efforts to reform energy policy "do not involve, or signal, a change in NRDC's long-held concerns about the role of nuclear energy in the country's generation mix."18
  • In 2007, in response to a beat-up about environmental support for nuclear power, Fairness & Accuracy in Reporting (FAIR) reported: "Instead of a story about a growing fervor for nuclear power among some environmentalists, the story is really one about a growing fervor to resurrect nuclear power among corporate and political elites, aided by a handful of mainly environmentalists-for-hire."19
  • In 2014, the BBC (and others) falsely claimed that Friends of the Earth UK was turning in support of nuclear power.20
  • In 2009−10, the World Nuclear Association heavily promoted a dishonest article claiming that Greenpeace UK had changed its stance on nuclear power.21


1. Steve Clemmer, Jeremy Richardson, Sandra Sattler, and Dave Lochbaum, Nov. 2018, 'The Nuclear Power Dilemma: Declining Profits, Plant Closures, and the Threat of Rising Carbon Emissions ', Union of Concerned Scientists,

2. Oliver Milman, 14 Nov 2018, Closing nuclear plants risks rise in greenhouse gas emissions, report warns',

Media statement: 9 Nov 2018, 'Former NRC Chair Statement on the Union of Concerned Scientists' report embracing nuclear power'

3. Oliver Milman, 14 Nov 2018', Closing nuclear plants risks rise in greenhouse gas emissions, report warns',

4. Mark Lynas, 15 Nov 2018, 'Environmentalists must embrace nuclear power to stem climate change',

5. Lindsey Walter and Ryan Fitzpatrick, 15 Nov 2018, 'Nuclear Closures and Climate Risks: Adding Context to UCS's Eye-Popping New Report',

6. Breakthrough Institute, 14 Nov 2018, 'The dam has broken',

7. Ted Nordhaus, 8 Nov 2018, 'A New Day for Nuclear Advocacy…and Environmentalism?',

8. Nuclear Monitor #867, 15 Oct 2018, 'IPCC bets on the renewables revolution',

9. Boston Globe ‒ Editorial, 9 Nov 2018, 'To fight climate change, environmentalists say yes to nuclear power',






15. Steve Clemmer, 16 Nov 2018, 'Seven Things People Got Wrong with UCS' 'Nuclear Power Dilemma' Report',


17. Ken Kimmell, 8 Nov 2018, 'Why We're Taking a Hard Look at Nuclear Power Plant Closures',
18. Nuclear Monitor #826, 6 July 2016, 'Manufacturing dissent: environmentalists and nuclear power',

19. FAIR, 22 Aug 2007, 'NPR Touts Pro-Nuke 'Environmentalists': Network's own nuclear links undisclosed',

20. 18 Sept 2014, 'Friends of the Earth UK's position on nuclear power', Nuclear Monitor #791,

21. World Nuclear Association, 13 Oct 2009, 'Greenpeace changes the politics',

Other stages of the nuclear fuel cycle

Nuclear Monitor Issue: 

The Union of Concerned Scientists summarises water issues associated with uranium fuel fabrication [1]:

Processing uranium requires mining, milling, enrichment, and fuel fabrication, all of which use significant quantities of water.

  • Mining − Uranium mining consumes one to six gallons (3.8−22.7 litres) of water per million Btus of thermal energy output, depending on the mining method. Mining uranium also produces waste that can contaminate local water sources, and which can be especially dangerous given the radioactivity of some of the materials involved. (A Btu or British Thermal Unit is a measure of energy content, usually used to describe the energy content of fuels. One kilowatt hour is the rough equivalent of 3,400 Btus.)
  • Processing − Uranium processing consumes seven to eight gallons (26.5−30.3 l) of water for every million Btus of thermal output.
  • Milling − The milling process uses a mix of liquid chemicals to increase the fuel's uranium content; milling leaves behind uranium-depleted ore that must be placed in settling ponds to evaporate the milling liquids.
  • Enrichment − The next step, enriching the gaseous uranium to make it more effective as a fuel accounts for about half of the water consumed in uranium processing. The conventional enrichment method in the US is gas diffusion, which uses significantly more water than the gas centrifuge approach popular in Europe.
  • Fuel Fabrication − Fabrication involves bundling the enriched uranium into fuel rods in preparation for the nuclear reactor. 

At the 'back end' of the nuclear fuel cycle, the large commercial reprocessing plants in France and the UK are major sources of radioactive marine pollution. Cogema's reprocessing plant at La Hague in France, and the Sellafield reprocessing plant in the UK, are the largest sources of radioactive pollution in the European environment.[2]

[1] Union of Concerned Scientists, 'Water for Nuclear',
[2] WISE-Paris, Study on Sellafield and La Hague commissioned by STOA,

More information:
Friends of the Earth, Australia, 'Impacts of Nuclear Power and Uranium Mining on Water Resources',

How much water does a nuclear power plant consume?

Nuclear Monitor Issue: 

First, a definition and some generalisations. Consumption is the net water loss from evaporation and equals the amount of water withdrawn from the source minus the amount returned to the source. With cooling towers, the amount of water withdrawn from the source is similar to consumption. With once through cooling, withdrawal is vastly greater than consumption. But overall consumption is greater with cooling towers than with once through cooling. Generally, cooling towers reduce the impacts on aquatic life but increase water consumption. For coastal sites, the loss (consumption) of water is rarely if ever a problem but the impacts on marine life (and other environmental impacts) can be significant.

Woods [1] gives figures of 1,514 to 2,725 litres of water consumption per megawatt-hour (MWh) for nuclear power reactors and the Nuclear Energy Institute gives identical figures.[2] For a 1 GW reactor, that equates to daily water consumption of 36.3 to 65.4 million litres. The lower figure is for once-through cooling, the higher figure is for systems using cooling towers (a.k.a. closed-loop, recirculating).

A 2009 World Economic Forum (WEF) paper gives a near-identical figure for closed-loop cooling (2,700 l/MWh) − plus 170−570 l/MWh for uranium mining and fuel production, giving a total of 2,870 to 3,270 l/MWh (68.9 to 78.5 million litres daily) .[3]

For coal, the WEF paper gives figures of 1,220 to 2,270 l/MWh (including mining).

For gas, the WEF paper gives figures of 700 to 1,200 l/MWh, and the Nuclear Energy Institute gives figures of zero (dry cooling) to 380 l/MWh (once through cooling) to 1,400 l/MWh (cooling towers).

The Nuclear Energy Institute claims that hydro plants consume 17,000 l/MWh, largely due to evaporation from reservoirs. The Nuclear Energy Institute further states that "renewable energy sources such as geothermal and solar thermal consume two to four times more water than nuclear power plants", without providing any details or references, and without noting that some renewable energy sources (such as wind and solar PV) use negligible water.

Some nuclear advocates promote the potential role of nuclear power in addressing some water problems, e.g. low-carbon desalination. But such proposals raise familiar problems − for example Syria's pursuit of a nuclear-powered desalination plant may have masked weapons ambitions and is believed to have been abandoned because of US pressure. Nuclear advocates are on stronger ground when they note that there is no need for nuclear plants to be located adjacent to their fuel source (typically 180 tonnes of low enriched uranium fuel annually for a 1 GW reactor); thus for example inland coal-fired power plants adjacent to coal mines can be replaced by coastal nuclear plants.

The Union of Concerned Scientists gives the following figures for water withdrawal (as opposed to consumption)[4]:

  • with closed-loop recirculating cooling, water withdrawal ranges from 3,000−9,800 l/MWh (72−235 million litres daily for a 1GW reactor);
  • with once through cooling, withdrawal is far greater at 95,000−227,000 l/MWh (2.3−5.4 billion litres daily for a 1 GW reactor; 0.84−1.97 trillion litres annually).


The Nuclear Information and Resource Service notes that a typical once-through cooling system draws into each reactor unit more than one billion gallons (3.8 billion litres) of water daily, 500,000 gallons (1.9 million litres) per minute.[5]

[1] Guy Woods, Australian Commonwealth Department of Parliamentary Services, 2006, 'Water requirements of nuclear power stations',
[2] World Economic Forum in partnership with Cambridge Energy Research Associates, 2009, 'Energy Vision Update 2009, Thirsty Energy: Water and Energy in the 21st Century',
[3] Nuclear Energy Institute, November 2012, Water Use and Nuclear Power Plants,
[4] Union of Concerned Scientists, July 2013, 'Water-Smart Power: Strengthening the U.S. Electricity System in a Warming World', or
[5] Nuclear Information and Resource Service, 'Licensed to Kill',


Water and Power Plants

Nuclear Monitor Issue: 

This is a summary of a Union of Concerned Scientists (UCS) report released in July 2013 − 'Water-Smart Power: Strengthening the U.S. Electricity System in a Warming World'. The report is posted at or use this shortcut:

The power sector is built for a water-rich world. Conventional fossil-fuel and nuclear power plants require water to cool the steam they generate to make electricity. At some power plants, a lot of the water they withdraw gets evaporated in the cooling process; at others, much of the water is discharged back to its source (albeit hotter). The bottom line: Most power plants need a huge, steady supply of water to operate, and in hot dry summers, that water can become hard to secure. 

As climate change brings extreme heat and longer, more severe droughts that dry up − and heat up − freshwater supplies, the US electricity system faces a real threat. Shifting to less water-intensive power can reduce the risk of power failures and take pressure off our lakes, rivers, and aquifers.

The phrase "energy-water collision" refers to the range of issues that can crop up where our water resources and the power sector interact. The UCS report provides some recent examples of each type of collision:

  • Not enough water: Heat and drought in Texas in 2011 caused water levels in Martin Creek Lake to drop so low that Martin Creek Power Plant had to import water from the Sabine River to cool its coal-fired plant and keep it operating.
  • Incoming water too warm: During a 2006 heat wave, incoming Mississippi River water became too hot to cool the two-unit Prairie Island nuclear plant in Minnesota, forcing the plant to reduce output by more than 50%. In the first such case in northern New England, the Vermont Yankee nuclear plant was forced to reduce its power production by as much as 17% over the course of a week in the Summer of 2012 due to high water temperatures and low flow in the Connecticut River. One of the two reactors at the Millstone nuclear plant, Connecticut, was shut down for 11 days in mid-July 2012 as its water source, Long Island Sound, got too warm − this was the first open-water collision on record and signals that even plants on large bodies of water are at risk as temperatures increase.
  • Outgoing water too warm: To prevent hot water from doing harm to fish and other wildlife, power plants typically aren't allowed to discharge cooling water above a certain temperature. When power plants bump up against those limits, they can be forced to dial back power production or shut down. Alabama's Browns Ferry nuclear plant, on the Tennessee River, has done that on several occasions in recent years − cutting its output during three of the past five summers, for example, and for five consecutive weeks in one of those years (2010). In the Summer of 2012, four coal plants and four nuclear plants in Illinois each sought and received "thermal variances" from the state to let them discharge hotter water than their permits allow, even amidst extensive heat-related fish kills and tens of millions of dollars in fisheries-related losses.


Nuclear power cycle

The nuclear power cycle uses water in three major ways: extracting and processing uranium fuel, producing electricity, and controlling wastes and risks. Reactors in the US fall into two main categories: boiling water reactors (BWRs) and pressurised water reactors (PWRs). Both systems boil water to make steam (BWRs within the reactor and PWRs outside the reactor); in both cases, this steam must be cooled after it runs through a turbine to produce electricity.

Like other thermoelectric power plants, nuclear reactors use once-through and/or recirculating cooling systems. Once-through systems withdraw enormous amounts of water, use it once, and return it to the source. Recirculating (or closed-loop) systems circulate water between the power plant and a cooling tower. About 40% of nuclear reactors in the US use recirculating cooling systems; 46% use once through cooling. Recirculating cooling systems withdraw much less water than once through systems but they consume much of what they do withdraw, typically operate less fuel-efficiently, and cost more to install. Dry (air) cooling is not currently used in nuclear power generation due to high costs (although World Nuclear News reported on 17 April 2013 that an air cooling system is to be constructed for Loviisa's two pressurised water reactors in Finland.)

Boiling water reactors and pressurised water reactors use comparable amounts of water to produce a unit of electricity. Nuclear plants as a whole withdraw and consume more water per unit of electricity produced than coal plants using similar cooling technologies because nuclear plants operate at a lower temperature and lower turbine efficiency, and do not lose heat via smokestacks.

In addition to cooling the steam, nuclear power plants also use water in a way that no other plant does: to keep the reactor core and used fuel rods cool. To avoid potentially catastrophic failure, these systems need to be kept running at all times, even when the plant is closed for refueling.

During an accident, 10,000 to 30,000 gallons (38,000−114,000 litres) of water per minute may be required for emergency cooling.

Low-carbon power is not necessarily water-smart. Electricity mixes that emphasise carbon capture and storage for coal plants, nuclear energy, or even water-cooled renewables such as some geothermal, biomass, or concentrating solar could worsen rather than lessen the sector's effects on water. That said, renewables and energy efficiency can be a winning combination. This scenario would be most effective in reducing carbon emissions, pressure on water resources, and electricity bills. Energy efficiency efforts could more than meet growth in demand for electricity in the US, and renewable energy could supply 80% of the remaining demand.

Further reading:

  • Synapse Energy Economics, paper prepared for the Civil Society Institute, Sept 2013, 'Water Constraints on Energy Production: Altering our Current Collision Course',
  • Benjamin Sovacool, January 2009, 'Running On Empty: The Electricity-Water Nexus and the U.S. Electric Utility Sector', Energy Law Journal, Vol.30:11, pp.11-51.
  • Benjamin Sovacool and Kelly Sovacool, 2009, 'Identifying future electricity–water tradeoffs in the United States', Energy Policy, 37, pp.2763–2773.