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How safe are nuclear reactors?

Pacific Northwest nuclear sites could be problematic after natural disasters

Nuclear reactor safety has been center stage in national news since the U.S. recently announced the construction of the first nuclear reactor to be built in more than 30 years—the Georgia Vogtle plant. The announcement comes on the eve of the March 11
one-year anniversary of the 9.0 magnitude megathrust earthquake and tsunami that struck Japan. In the days after the catastrophic event, a series of malfunctions at the Fukushima I nuclear power plant resulted in one of the largest nuclear disasters in history. It caused worldwide concerns over nuclear reactor safety.

COURTESY OF US DEPT OF ENERGY
Hanford site workers on the front-face of the B-reactor during construction.

The number of nuclear reactors in the U.S. decreased over the past few years from 115 to just over 100. According to an article published on CNN’s website, 23 active reactors have the same design as the Fukushima I reactor, but the reactor’s designer, GE Hitachi Nuclear Energy, claims that the reactors are sound and reliable [“U.S. nuclear plants similar to Fukushima spark concerns,” Feb. 17, 2011]. But in the face of a catastrophic natural disaster like an earthquake, just how safe are these reactors?

Oregon has one nuclear power plant site just south of Rainier. Save for one building, the Trojan nuclear power plant was completely demolished in 2006. In fact, Oregon passed an initiative in 1980 that prohibits the licensing of reactors in Oregon unless approved by voters, and only then if there is a safe repository for nuclear fuel. “We are not likely to have one any time soon,” said Ken Niles, administrator of the Oregon Department of Energy Nuclear Safety division.

However, a problem remains with the Trojan site: That last building happens to be a storage facility where spent nuclear fuel is stored in large concrete and steel containers. Years of delay have prevented the federal government from moving the nuclear waste because a safe repository has not been found. And the Trojan site sits right on top of the Portland Hills Fault Line.

“Reactors get built on fault lines because some geologists convince others that the fault is no longer active and therefore safe,” wrote Scott Burns, professor of geology at Portland State, in an email. “The Portland Hills Fault is very debatable.”

However, Niles said the Trojan site is no cause for concern. “Even if there was an earthquake, not much could happen,” he said. The worst-case scenario, he said, would be for one of the tanks to topple or split—the waste is solid material, so it wouldn’t spread. There are no incendiary materials or resources nearby, so at the worst, he said, it would cause a hazard for the immediate vicinity but not the state as a whole.

Eastern Washington has the only other nuclear site in the Pacific Northwest—The Hanford site on the Columbia River. The reactor itself is decommissioned, but the Columbia Generating Station, a commercial reactor, remains active. Hanford’s main purpose was to create plutonium for use in nuclear weapons. This creates a far different situation from the Trojan site.

“There are a huge amount of contaminates, and if there was a fire, it could spread,” Niles said, adding that there are other potential hazards and “aging underground waste storages.”

Hanford is located in an area with slight seismic activity. According to Erik Sanchez, associate professor of physics at PSU, the site would be hazardous if the fuel tanks were compromised. The site is part of the world’s largest environmental cleanup effort. However, even Hanford is unlikely to be much of a threat in the case of a natural disaster. It and the Columbia Generating Station are too far inland to be affected by a tsunami, and the seismic activity in the area is low.

“Believe me, the owners and the Nuclear Regulatory Commission have looked at the situation in that respect,” Niles said. The NRC is responsible for making sure U.S. reactors don’t have the same failings as the plant in Japan and have extended requirements for a reactor’s personal battery and generator supply. Having numerous power supplies is important as well, so reactors can work without power for some time.

According to Sanchez, the problem with the emergency power at the Japan plant was that the batteries and generators were not installed at a sufficient elevation and were susceptible to the tsunami. Additionally, they were not in water-tight rooms. The earthquake and the tsunami destroyed or bypassed most of the emergency power sources.

Public outcry after the nuclear disaster caused the closing of all reactors in Japan for inspection, and other countries like Germany followed suit.

“[The Japanese] are very fast in general when cleaning up and re-building; they are doing good work with cleanup and recovery, but it will take years,” wrote Yumei Wang, geotechnical engineer and geohazards team leader at the Oregon Department of Geology and Mineral Industries, in an email.

Following the disaster in Japan, the NRC created the Japan Lessons-Learned Project Directorate. Composed of more than 20 full-time experts, its purpose is to examine what went wrong in Japan and determine how U.S. plants can avoid a repeat of the incident. Additionally, the Japan task force issued three tiers of recommendations for U.S. reactors. The first tier includes recommendations for immediate implementation.

According to the NRC website, tier one recommendations include “seismic and flood hazard reevaluations, seismic and flood walkdowns, station blackout regulatory actions, reliable hardened vents for Mark I and Mark II containments, [and] strengthening and integration of emergency operating procedure,” among others. The NRC intends to issue these orders by March 11.

As for if nuclear reactors are safe, Niles cites the lack of opposition to re-licensing efforts, which extend the Columbia Generating Station’s operating time for another 20 years, as evidence enough. “We believe it is being regulated and operated appropriately. We are comfortable with it,” he said.

Sanchez said that if there was a 9.0 earthquake in the U.S., reactors wouldn’t be the biggest concern. “In my opinion, nuclear plants in the U.S. are generally safe, but who can predict a calamity with all the problems associated with a 9.0 earthquake? The situation in Japan was an unusual event.”

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