Water: The nuclear industry's Achilles' heel

Senator Barbara Boxer, the chairwoman of the Senate’s Committee on Environment and Public Works, recently brought added attention to the nuclear industry when she said, "there will be a nuclear title in the bill" referring to the American Clean Energy and Security Act making its way through the Senate.  The WSJ reports that "Senate Republicans have been clamoring for more federal support for nuclear power as an emissions-free power source on par with wind or solar power"; emission free, but significantly more water intensive.

There are currently 26 proposed plans for new nuclear reactors in the U.S.  Idaho, Utah, Texas, Missouri, Louisiana, Mississippi, Alabama, Florida, Georgia, South Carolina, North Carolina, Virginia, Maryland, Pennsylvania, New York, Ohio, Tennessee, and Michigan have all proposed new nuclear plant sites, according to the World Nuclear Association.  A majority of these sites are located in the drought-prone Southeastern U.S.

The World Nuclear Association reports these facts:

• The USA is the world's largest producer of nuclear power, with more than 30% of worldwide nuclear generation of electricity.
• The country's 104 nuclear reactors produced 809 billion kWh in 2008, almost 20% of total electrical output.
• Following a 30-year period in which few new reactors were built, since mid-2007 there have been 17 licence applications to build 26 new nuclear reactors.
• Government policy changes in the last 10 years have helped pave the way for significant growth in nuclear capacity. Government and industry are working closely on expedited approval for construction and new plant designs.

According to Wikipedia, "as of 2007, Watts Bar 1 (in Tennessee), which came on-line in February 1996, was the last U.S. commercial nuclear reactor to go on-line. The amount of time since then with no new reactos is often quoted as evidence of a successful worldwide campaign for nuclear power phase-out"; but the hiatus in new nuclear plant building is scheduled to come to a close in the next decade, and the U.S. is poised to begin a massive nuclear power plant buildout phase.

"There are three regulatory initiatives which enhance the prospects of building new plants in the next few years. First is the design certification process, second is provision for early site permits (ESPs), and third is the combined construction and operating licence (COL) process. All have some costs shared by the DOE.  New reactor construction is expected to get under way early in the next decade," according to the World Nuclear Association.

Map of the U.S. showing the locations of operating nuclear power reactors.

Click on the map above to open up an interactive map.

While nucelar power has numerous problems to overcome in terms of national security and radioactive waste, the nuclear industry's major limitation is water.  The nuclear water problem may negate any emission reduction benefits in the longterm.

Without reliable copious amounts of water to cool the waste steam, nuclear power plants run the risk of being forced to drop power output levels or shut down temporarily, forcing them to draw more expensive emergency energy from other sources. "Nuclear reactors across the Southeast could be forced to throttle back or temporarily shut down later this year (2008) because drought is drying up the rivers and lakes that supply power plants with the awesome amounts of cooling water they need to operate," MSNBC reports.

How much water does one reactor use?  That depends on what kind of cooling technology is featured in the plant. (PowerScorecard)

• Closed-cycle systems discharge heat through evaporation in cooling towers and recycle water within the power plant. The water required to do this is comparatively small since it is limited to the amount lost through the evaporative process. Because of the expense associated with closed-cycle cooling, once-through systems are far more common.
  
  
• Once-through systems require the intake of a continual flow of cooling water. The water demand for the once-through system is 30 to 50 times that of a closed cycle system.

Water that evaporates is considered consumed, and water that recycles back into rivers and lakes is considered used; but before being released back into natural systems the water needs to be cooled.

"The Harris reactor in N.C., for example, sucks up 33 million gallons a day, with 17 million gallons lost to evaporation via its big cooling towers. Duke’s McGuire plant draws in more than 1 billion gallons a day, but most of it is pumped back to its source." (MSNBC) 

The water used to cool the core circulates through a closed-cycle, so there is little danger of running a shortage of available water so severe that reactors overheat.  Instead, regional water shortages in lakes and streams in the area where reactors are would make it so that there was not enough available water to satisfactorally cool the steam before being rereleased back into the environment.  Plants would have to shut down temporarily until there was enough water available to cool the steam for rerelease.  These shutdowns are not optimal; nuclear plants perform best when they remain operational.

"Nuclear plants are subject to restrictions on the temperature of the discharged coolant, because hot water can kill fish or plants or otherwise disrupt the environment."  The droughts in the Southeastern U.S. last year cuased water levels to lower to levels that forced the shutdown of nuclear reactors in the area while more water was pumped into the feed lakes surrounding the plants.  When competition for available freshwater heats up in drought years, agricultural and residential water needs may become compromised.

In San Antonio, CPS and NRG Energy have negotiated a contract for 102,000 acre feet of water from the Lower Colorado River Authority.  This amount of water is equal to half of San Antonio's annual water needs.  (San Antonio Express)

"For every three units of energy produced by the reactor core of a U.S. nuclear power plants, two units are discharged to the environment as waste heat. Nuclear plants are built on the shores of lakes, rivers, and oceans because these bodies provide the large quantities of cooling water needed to handle the waste heat discharge," says the Union of Concerned Scientists.  Read the pdf document from UCS here.

The question we should be asking ourselves is whether America has enough freshwater necessary to cool the proposed new nuclear power plants being proposed.  While it is possible to use saltwater, it corrodes the intake pipes and other plant equipment faster.  Freshwater is optimal.  At inland nuclear reactor sites, saltwater is not an option; these types of plants will compete for increasingly limited water supplies.

Here is a water usage comparison table for nuclear, coal, oil, wind, and solar:

WATER CONSUMPTION--CONVENTIONAL POWER PLANTS

Technology

gallons/kWh

liters/kWh

---

Nuclear 0.62 2.30 Coal 0.49 1.90 Oil 0.43 1.60 Combined Cycle 0.25 0.95

WATER CONSUMPTION--WIND AND SOLAR

Technology

gallons/kWh

liters/kWh

---

Wind [1] 0.001 0.004 PV [2] 0.030 0.110

We are back to some of the same question we are asking ourselves in terms of coal-fired power plants.  Do nuclear reactors, while being relatively financially cheap while reducing emissions, have other costs that make them less attractive than their solar and wind counterparts?  How will climate change affect the areas where new nuclear plants are being proposed?  Do we have enough water to meet societal needs if we increase the amount going toward nuclear reactors?  Will electricty in areas that are dependent upon nuclear power really be cheaper than other sources if the nuclear plants have to shut down because of low water levels?  How does the constant shutting down and turning nuclear reactors back on affect overall service and repair costs?

Water should be a determining factor is considering which energy sources we are going to use in the future to power our energy demands.

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