OLR Research Report

May 26, 2010




By: Kevin E. McCarthy, Principal Analyst

You asked for background on nuclear power in Connecticut. You were specifically interested in learning (1) the proportion of power generated in the state that comes from nuclear plants, (2) the prospects of additional nuclear capacity being added in the state, (3) the state of knowledge regarding nuclear plant safety, and (4) where waste generated in Connecticut is disposed of.


Slightly more than half of the power produced in Connecticut in 2009 was produced from the Millstone nuclear powers plants, although it is not possible to determine what proportion of the power generated by the plants is ultimately consumed in Connecticut. It appears unlikely that additional nuclear capacity will be built in Connecticut in the foreseeable future because of regional and state-specific market conditions. Regionally, electric demand has fallen in recent years and it appears unlikely that substantial new generation will be needed soon. In addition, Connecticut has a law that appears to preclude the construction of a new nuclear power plant until there is a long-term resolution of the issue of nuclear waste disposal.

No nuclear power plant accident in this country has harmed a member of the public in the history of U.S. commercial nuclear power. The industry is subject to very extensive safety regulations administered by the Nuclear Regulatory Commission (NRC). Nonetheless, accidents at

Three Mile Island and Chernobyl resulted in meltdowns and, in the latter case, injuries and fatalities. A number of environmental groups have raised concerns regarding nuclear safety.

The low-level radioactive waste (LLRW) produced in Connecticut is disposed of in South Carolina. Spent nuclear fuel is initially stored in pools of water located at the plants. Some of this waste has been transferred to casks that are stored on-site in concrete bunkers.


The Millstone nuclear power plants account for about 55% of the power generated in the state in 2009, according to the Connecticut Siting Council. This is somewhat higher than the historical average, in part because the NRC authorized Millstone 3 to increase its generating capacity by about 7% in 2008. The plant's owner accomplished this primarily by upgrading major plant components such as turbines and transformers.

The power produced at Millstone is sold on the regional wholesale market to third parties such as hedge funds and can be resold to various participants in the wholesale market. While it is possible that these buyers ultimately sell part of the power to Connecticut electric utilities, there is no way of determining what proportion, if any, of the nuclear power generated in the state is consumed in the state.

About 30% of the electricity sold in the New England regional market was generated from nuclear power in 2009, according to the Independent System Operator-New England, which administers the market.


Market Conditions

Connecticut and New England currently have ample generation resources in light of current and projected demand. The 2009 Connecticut Siting Council forecast of loads and resources projects that total demand in the state will decrease slightly between 2009 and 2018, from 31,980 megawatt-hours (MWH) to 31,394 MWH. The Independent System Operator-New England (ISO-NE), which administers the regional wholesale electric market, projects slight growth during this period (32,710 MWH to 33,850 MWH).

In February 2009, DPUC issued its final decision in its review of the electric companies' Integrated Resource Plan (IRP). In that decision, DPUC noted the electric companies' IRP finding that Connecticut's local resources will be adequate for its needs for the foreseeable future. This assumes no retirements of existing generation, and the addition of planned plants, as well as planned demand-side management resources and transmission upgrades.

State-specific Factors

CGS 22a-136 bars the construction of a fifth nuclear power facility until the Commissioner of Environmental Protection finds that the United States has identified and approved a demonstrable technology or means for the disposal of high level nuclear waste. (When the law was adopted, the state had four nuclear power plants, two of which were subsequently closed).

The disposal of high level waste has been highly contentious and the Obama administration has directed the Department of Energy (DOE) to withdraw its application with NRC to build a high level waste repository at Yucca Mountain in Nevada. The commission has stated it will not act on DOE's motion to withdraw its application until the court system rules on related lawsuits.

While it is unclear whether CGA 22a-136 would bar the construction of a new nuclear plant in the state, it does add uncertainty which could substantially affect the economics of any future nuclear expansion.

Another uncertainty is the future of the Kleen Energy plant in Middletown. The plant was the site of an explosion that occurred when it was approximately 96% completed that killed six people and caused extensive damage. It is not clear whether or when the plant will go into operation. Again, this adds uncertainty to the wholesale electric market.


Low Level Waste

LLRW includes items that have become contaminated with radioactive material or have become radioactive through exposure to radiation. This waste includes contaminated protective shoe covers and clothing, reactor water treatment residues, equipment and tools, among other things.

Connecticut, together with New Jersey and South Carolina, comprise the Atlantic Interstate LLRW Management Compact. LLRW from the member states is shipped to Barnwell, South Carolina for disposal. The facility is operated by Chem-Nuclear Systems on land the state of South Carolina owns. Further information about the facility is available at http://www.chemnuclear.com/disposal.html.

Spent Nuclear Fuel

The spent fuel from the Millstone nuclear plants is initially stored in a fuel pool located near the refueling cavity of each plant. The pool is filled with water, and the fuel assemblies are lowered into storage racks in the pools. The racks, along with neutron-absorbing materials in the water, serve to prevent the fission process from recurring. The water also cools the fuel. The pools are located in the plants' containment structures.

Over time the spent fuel becomes less radioactive. Dominion (Millstone's owner) has moved spent fuel from Millstone 2 and from the former Connecticut Yankee plant into dry cask storage. The fuel is placed in a cask (a steel canister) that is capable of holding 32 fuel assemblies. Once filled, the lid on the canister is welded in place to ensure the radioactive material is permanently isolated from the environment. The fuel is sealed in the canister and it will not be touched again before being shipped by DOE to the federal used fuel repository, if and when it opens.

The canisters, which weigh more than 40 tons fully loaded, are then inserted into horizontal storage modules. The modules are steel reinforced concrete bunkers that are approximately 20 feet high, 10 feet wide and 20 feet deep, with walls and roof up to 5 feet thick. The modules are located within protected area of the plants.

The NRC periodically inspects the design, fabrication, and the use of dry casks, to ensure licensees and vendors are performing activities in accordance with radiation safety and security requirements, and licensing and quality assurance program commitments. An NRC website, http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/dry-cask-storage.html, provides additional information on this storage technology.


Nuclear power plants are built with redundant safety systems and backup power supplies so these systems are available, if needed, when maintenance is being performed on the plant. The Nuclear Energy Institute, an industry-supported body, notes that reactors are typically protected by about four feet of steel-reinforced concrete with a thick steel liner, and the reactor vessel is made of steel about six inches thick. Steel-reinforced concrete containment structures are designed to withstand the impact of hurricanes, tornadoes, floods, and airborne objects, such as commercial jets. Further information about these measures is available at http://www.nei.org/keyissues/safetyandsecurity/. NRC reviewed the safety of Millstone's nuclear steam supply systems, instrumentation and control systems, electrical systems, accident evaluations, radiological safety, and operations and training, among other things, when it approved the expansion of generating capacity in 2008.

DOE notes that no nuclear power plant accident has harmed a member of the public in the history of U.S. commercial nuclear power, http://www.ne.doe.gov/pdfFiles/NPPSOPPS.PDF. While the 1979 accident at Three Mile Island resulted in a partial core meltdown, it led to no deaths or injuries among plant workers or members of the local community. The NRC believes that the subsequent consolidation of the nuclear industry resulting in a few operators owning multiple plants has made the operation of U.S. plants safer, more cost-effective, and more reliable.

In contrast, the 1986 meltdown at the Chernobyl plant in Ukraine did result in injuries and fatalities. A 2005 report prepared by the International Atomic Energy Agency and World Health Organization attributed fewer than 50 direct deaths from the meltdown but estimated that there may be up to 4,000 additional cancer deaths over time among the most highly exposed people. However, the Chernobyl reactor lacked a number of key safety components that are present at U.S. nuclear plants. A 2009 NRC review of the Chernobyl disaster stated that U.S. reactors have different plant designs, broader shutdown margins, and operational controls to protect them against the combination of lapses that led to the accident at Chernobyl. The report is available at http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/chernobyl-bg.html.

There have been a number of subsequent close calls in this country, most notably at the Davis-Besse plant in Ohio. An inspection of the reactor vessel head in 2002, during reactor shutdown, found a hole the size of a pineapple in the vessel head next to one of the reactor control rod drive mechanisms, caused by boric acid leakage and corrosion. The corrosion ate through the 6.5-inch thick carbon steel, leaving only a 3/8-inch stainless steel liner to hold back pressures of more than 1 ton per square inch. The hole seriously jeopardized the integrity of the reactor vessel. While the fault was discovered before the reactor was restarted, it disclosed a failure by the plant owners to respond to earlier indications of a problem. The plant was shut down for two years and the problem cost the plant's owner more than $600 million in repairs and replacement energy costs. The company also paid a $28 million fine. In February 2010, the plant was shut again when cracks were discovered in the nozzles of the reactor head. On May 4, 2010, the plant's owner announced that it does not anticipate restarting the plant until July 2010.

Opponents of nuclear power continue to raise a number of safety concerns. They point to more than two dozen older U.S. reactors that have leaked radioactive tritium from underground pipes. According to the NRC's February 2010 "Fact Sheet on Buried Pipes at Nuclear Reactors," corrosion at these plants has caused leaks in buried pipes and related systems, contaminating groundwater with minor levels of radioactive material. The Union of Concerned Scientists has been one of several organizations that have been critical of NRC's response to this problem, as indicated in this letter to the NRC, http://www.ucsusa.org/assets/documents/nuclear_power/20100422-ucs-nrc-groundwater-followup.pdf. Another concern has been the vulnerability of emergency water pumps.