Trojan Nuclear Plant Is Retired

Date January 4, 1993

The Trojan nuclear power plant was retired after seventeen years of service because the safety of its deteriorating steam generators was questioned and the generators were too expensive to replace.

Locale Rainier, Oregon

Key Figures

• Lloyd Marbet (fl. late twentieth century), spokesman for the Don’t Waste Oregon Council
• Robert D. Pollard (fl. late twentieth century), member of the Union of Concerned Scientists
• Joram Hopenfeld (fl. late twentieth century), scientist with the Nuclear Regulatory Commission’s Reactor and Plant Safety Issues branch
• Ken Harrison (fl. late twentieth century), chairman and chief executive officer of Portland General Electric Company

Summary of Event

On January 4, 1993, the Trojan nuclear power plant, which had been licensed to operate until 2011, was shut down permanently. Portland General Electric Company (PGE) closed the seventeen-year-old plant because of rising repair costs and regulatory uncertainty at both the state and federal levels concerning the safety of Trojan’s deteriorating steam generator tubes. Located forty miles north of Portland, Oregon, on the Columbia River, the 1.13 million-kilowatt plant began producing electricity in 1976. It operated at an average annual capacity of 52 percent, supplying 10 to 15 percent of Oregon’s electricity and 25 percent of PGE’s customer demand.

The Trojan plant was a pressurized water reactor (PWR). In a PWR, uranium fuel in the reactor’s core undergoes fission, producing tremendous heat. This heat flashes water to steam, which drives turbines and a generator to produce electricity. The uranium fuel rods in the reactor core of a PWR must be constantly covered with water to prevent them from overheating, melting down, and possibly releasing radioactive material into the environment. At Trojan, 88,500 gallons of water per minute circulated through the reactor coolant system, absorbing heat and radioactivity from the core and being warmed to 617 degrees Fahrenheit. A constant pressure of 2,250 pounds per square inch within the system prevented the water from boiling. From the core, this water flowed into four steam generators, filling thousands of tall, U-shaped tubes in each. Water from the steam system within each generator, maintained at a pressure of 900 pounds per square inch, flowed over the outsides of the tubes and was flashed to steam by the heat of the water inside.

The condition of steam generator tube walls is critical to safe operation of a nuclear power plant, because the walls form the barrier that keeps the radioactively contaminated water in the reactor coolant system. Over time, the higher pressure within the tubes, the water chemistry, and operational vibration can cause cracking and pitting of tube walls. The pressure differential between the reactor coolant system and the steam system will drive contaminated water into the steam system through any cracks that penetrate the walls. If the pressure differential between the two systems increases suddenly—for example, when a main steam line breaks—new cracks may develop and existing cracks may leak copiously or even rupture. If enough water escapes to deplete seriously the reactor cooling system and its emergency backup system, the core will melt down, releasing quantities of radioactive material into the steam system, from which it may escape into the environment.

The Nuclear Regulatory Commission (NRC) regulates the operation of nuclear power plants in the United States. According to NRC-established criteria, steam generator tubes must be inspected periodically, and tubes with even microscopic cracks more than 40 percent deep must be plugged or strengthened by insertion of a sleeve.

For the last ten years of its operation, Trojan was increasingly plagued by deterioration of its steam generator tubes. In spring, 1991, inspection during the plant’s annual refueling and maintenance outage revealed thousands of tubes that required attention. By the end of the year, 20 percent of Trojan’s tubes had been plugged, and many others had been sleeved. In addition, 428 tubes had microcracks of varying depths where they passed through the tube support plates.

On December 15, 1991, PGE submitted a license-change application to the NRC, asking that the Trojan plant be allowed to return to service for a one-year cycle without repairing the 428 tubes, stating that the three-quarter-inch-thick support plates surrounding the microcracking would prevent leakage or rupture. In return, PGE would agree to a reduction in the NRC-allowed leakage from the reactor coolant system, making it easier to detect the emergence of small leaks from microcracks and to take corrective action in time. The license-change amendment was issued on February 5, 1992, and Trojan returned to service on February 29, 1992, after being down for nearly one year.

Since the plant’s construction, Trojan had been the target of organized opposition by residents of the surrounding area who believed that the plant was unsafe. State referenda in 1986 and 1990 to close the plant had failed. The Don’t Waste Oregon Council (DWOC), sponsor of the 1990 referendum, repeatedly petitioned the Oregon Public Utilities Commission (OPUC) in 1990 and 1991 to include the cost of steam generator replacements in its consideration of the cost of electricity generated by Trojan. PGE was required, under the least-cost planning process imposed on Oregon utilities in 1989, to produce electrical power at the lowest cost consistent with the public’s long-range good. Replacement of the two most deteriorated generators at $100 million each would have forced closure of Trojan because alternative energy sources would have cost less. These petitions were denied.

In December, 1991, the DWOC petitioned the Oregon Department of Energy’s (ODOE) Energy Facilities Siting Council, which could revoke Trojan’s site certificate, to hold a hearing to investigate fully the degradation of Trojan’s steam generator tubes. This petition was denied.

Two more state referenda to close Trojan immediately were planned for the November, 1992, election. On August 10, 1992, PGE announced that, as a result of its most recent least-cost analysis, which had included the cost of replacing two generators, it would phase out Trojan by 1996. PGE believed that it could continue to operate profitably and safely until then at 60 percent capacity, allowing the company time to find substitute resources for Trojan. Both referenda failed. One week after the election, on November 9, 1992, Trojan went off-line again when monitors detected radioactive gas emissions. PGE attributed the leak to a faulty sleeve weld in a steam generator tube.

On November 23, 1992, internal NRC memoranda were leaked to Robert D. Pollard, a nuclear safety engineer for the Union of Concerned Scientists (UCS), who released them to the media. These memoranda increased concerns about the safety of Trojan among the public and state regulators of the plant in Oregon. The first memorandum, submitted in December, 1991, and augmented in March, 1992, by Joram Hopenfeld of the NRC Reactor and Plant Safety Issues branch, addressed the license-change amendment allowing Trojan to operate with 428 unrepaired tubes. The safety analysis submitted by PGE in support of its request for this amendment concluded that tubes with microcracks at support plates would not rupture at pressures typical of those in the break of a main steam line. Hopenfeld believed that depletion of reactor-cooling water leading to a meltdown could occur if enough tubes only leaked and that the likelihood of such a situation developing was far greater than had been expressed in PGE’s report.

The other memorandum, submitted in March, 1992, by Joseph Muscara, the research program manager for the NRC’s eleven-year steam generator tube integrity program, did not allude to Trojan but addressed a relevant issue. It expressed Muscara’s concern about the apparent movement of the NRC away from its long-standing policy of prohibiting plants with unrepaired steam generator tubes from operating. Muscara believed, based on years of research on steam generator tubes, that it was not possible to predict with accuracy how cracks in tube walls would develop during an operating cycle. It was therefore not possible to guarantee that a plant could operate safely with unrepaired tubes.

On December 1, 1992, NRC officials met with PGE officials to consider PGE’s request to return Trojan to service without additional analysis of other steam generator tubes. Antinuclear activists, opposed to Trojan’s being restarted without a public hearing that included testimony by Hopenfeld and Muscara, blocked the gate to the plant on both December 1 and December 3. A number of the activists were arrested, jailed, and charged with trespassing.

Shortly thereafter, PGE withdrew its request to restart Trojan and announced that it would conduct additional inspections of the tubes. As a result, on December 9, the ODOE, charged under state law with preventing Trojan from operating if clear evidence of an immediate danger to the public existed, urged the NRC to participate in a public hearing in Oregon regarding safety issues at Trojan.

On January 4, 1993, PGE closed Trojan permanently, stating that it was confident that Trojan could operate safely but was no longer certain that it could operate profitably because of probable future downtime for regulatory hearings and repairs. PGE had also determined that abundant replacement power resources would be available in the Northwest for the next few years. Shutting Trojan down immediately rather than operating it until 1996 had become the least-cost option.

Significance

Trojan’s closing eliminated the threat of a core meltdown but posed new environmental issues related to the storage of spent nuclear fuel, plant decommissioning, and replacement of the power previously generated by the plant. In January, 1993, the 193 partially used fuel assemblies were transferred from Trojan’s reactor to its spent-fuel pool. The pool housed 781 fuel assemblies—every fuel assembly used at Trojan since it began operation in 1976—or approximately 450 tons of spent fuel. Originally designed to hold one year’s worth of spent fuel until it could be reprocessed, the pool was reracked to hold more when reprocessing was made illegal in the 1970’s under Jimmy Carter’s presidential administration.

The Nuclear Waste Policy Act of 1982 and its amendment in 1987 required nuclear power plants to store their spent fuel on-site until January, 1998, when the federal government would assume responsibility for it. By then, the United States would have forty thousand metric tons of spent fuel—high-level radioactive waste—stored at some seventy sites awaiting disposal. The U.S. Department of Energy (DOE) predicted, however, that its proposed permanent repository for high-level radioactive waste, Nevada’s Yucca Mountain, would not be ready to accept waste until at least 2010. The DOE was not developing a temporary facility for storing waste in the interim. On June 20, 1994, PGE and thirteen other utility companies filed suit against the federal government to force it to begin providing storage for spent reactor fuel.

Did the storage of spent fuel at Trojan after closure pose an environmental risk? In the 1980’s, geologists demonstrated the potential of a severe earthquake in the Pacific Northwest. Both the NRC and the ODOE concluded that Trojan’s used-fuel storage facility could withstand the largest credible earthquake for the region. Others were less certain, however. A seismic fault line lies beneath the Columbia River near the plant, and there are fractures in the base rock under the plant. One fracture passes under the spent-fuel pool. If an earthquake were to rupture the pool and the water level dropped, the fuel assemblies could ignite and burn, releasing radioactive material.

Early in 1994, at the Dresden nuclear plant in Illinois (retired in 1978), a pipe ruptured during freezing weather, and fifty-five thousand gallons of water leaked from the spent-fuel pool. Consequently, the NRC required a safety inspection of Trojan’s pool in April, 1994, and began developing an inspection program focused on spent-fuel pools at retired plants.

Do staff cutbacks at closed plants pose an environmental safety issue? The NRC granted a possession-only license to PGE on March 24, 1994, enabling it to reduce its staff at Trojan from 1,100 employees to approximately 150 employees. In June, 1993, the NRC cited PGE for allowing equipment removed from the containment building to accumulate near the spent-fuel pool, stating that the equipment might fall into the pool during an earthquake and rupture a fuel assembly. The NRC attributed the accumulation of equipment around the pool to extensive staff cutbacks at Trojan.

Decommissioning of a nuclear power plant is the process of safely removing the plant from service and decontaminating it so that the site can be released for unrestricted use. Contaminated equipment and facilities may be decontaminated and left at the site or may be transported to low-level waste depositories, depending on plans for the site’s future use. Utilities are required by law to decommission closed plants.

PGE filed its decommissioning plan for Trojan in January, 1995. Decommissioning of Trojan was to begin in 1998 and was estimated to cost $500 million. In addition to high-level radioactive waste, there is a considerable amount of low-level radioactive waste in a plant the size of Trojan—enough waste to cover a football field to a depth of about five feet. This waste must be disposed of or decontaminated. In 1994, only two low-level waste-disposal sites were operating in the United States; PGE had access to one of these, U.S. Ecology, near Richland, Washington.

In July, 1994, PGE filed with the ODOE’s Energy Facilities Siting Council to move the four steam generators (four stories high and 330 tons each) and a pressurizing unit to U.S. Ecology in the fall, stating that it could save $4.5 million by disposing of these components before disposal rates increased in 1995. PGE planned to fill them with concrete and barge them 270 miles up the Columbia River. The DWOC sued to prevent this from occurring before Trojan’s decommissioning plan was reviewed by the public and approved by the siting council, citing the threat to the spent-fuel pool, workers, nearby residents, and the Columbia River of moving these large, radioactive components before their radioactivity had had a period of years in which to diminish.

Financing decommissioning has environmental implications. As part of its decommissioning regulations, the NRC expects utilities to collect, over the projected lifetimes of their plants, adequate funds to decommission in a safe and timely manner. If funding is inadequate, plant sites, facilities, and equipment may not be safely or completely decontaminated; equipment may not be disposed of at licensed facilities. Trojan’s decommissioning fund was planned to be collected from ratepayers over a forty-year span, thus PGE had collected only about $60 million when the plant closed. In the fall of 1993, PGE petitioned the OPUC for a rate increase to help cover the costs of decommissioning the plant. Protracted legal disputes and political negotiations over this controversial issue continued for several years. In November, 2000, Oregon voters resoundingly repudiated settlements by which the OPUC allowed PGE to recover more revenue in taxes, but the matter continued to move through litigation even as taxes were collected.

In the meantime, decommissioning continued. The reactor vessel was transported by barge up the Columbia River to the Hanford nuclear disposal site for permanent burial. The spent fuel was stored in thirty-four dry casks until it could be disposed of in the future at Yucca Mountain, and on May 21, 2006, the imposing, nearly five-hundred-foot cooling tower was demolished by dynamite implosion, a first in American nuclear plant history.

The generation of electricity by burning coal, oil, and natural gas produces hundreds of thousands of metric tons of environmentally damaging emissions each year in the United States. During the years it operated, the Trojan nuclear plant supplied 25 percent of PGE’s electricity demand and 10 to 15 percent of Oregon’s electricity demand without producing these damaging emissions. PGE replaced the electricity supplied by Trojan through construction of cogeneration projects fueled by natural gas, an aggressive energy-efficiency program to reduce customer demand, technological and operational improvements to the company’s existing generation and supply systems, and purchase of power from other suppliers.

Bibliography

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