While the funnel of the cooling tower of Arkansas Nuclear One near Russellville might look like the epitome of peacefulness - a white, curving monolith belching clouds of steam - the Nuclear Regulatory Commission once thought that if a fire broke out there in the wrong place, it could lead to disaster.
A report issued by the NRC in August 2001 said that the plant had internal design flaws at Entergy's nuclear plant which could, in the event of fire, lead to a failure of the pumps that cool the reactor core. That report was well-publicized at the time. And both the NRC and Arkansas Nuclear One spokesmen say that policy changes and fire patrols have since made the plant safe. But they also agree that physical alterations that could eliminate the problem once and for all have not been performed, and probably won't be.
Like most everything else in the modern world, the plant is dependent on electrical cables. Miles of cable snake through the building, but the most important to the Nuclear Regulatory Commission are those responsible for cooling and shutting down the reactor core in case of an emergency. As such, the NRC has instituted strict rules concerning the routing of these critical cables, with concern centering around coolant system redundancy - making sure that if the primary electrical system is knocked out, there is still a backup system to operate the pumps and valves necessary to keep the core cool and eventually coax it into dormancy.
"The nuclear industry, when it comes to safety, has to be the most conservative in the world," said Nuclear One spokesman Phil Fisher. "Because of that, the likelihood of all the systems not operating are extremely remote."
The regulations developed in response to past problems. As recounted in last month's issue of the Progressive magazine, a 1975 fire at the Browns Ferry Nuclear Plant in Alabama severed some 1,600 cables before firefighters were able to bring it under control, including 628 cables crucial to plant safety systems. A subsequent paper by the Union of Concerned Scientists said the plant was only spared a release of radiation by "sheer luck."
According to NRC regulations developed after the Browns Ferry incident (and after the completion of the first reactor at Arkansas Nuclear One in 1974), the primary and secondary electrical cables controlling core safety systems must be at least 20 feet apart at all times, with dedicated fire barriers and no combustible materials between the two. The NRC's August 2001 fire safety report on Arkansas Nuclear One found significant violations of these regulations. In two areas, redundant cable trains were routed less than 20 feet apart, through areas with multiple sources of possible ignition. An overhead sprinkler provided partial protection in one area, but another was protected only by smoke alarms.
Victor Dricks, spokesman for the NRC's regional office in Arlington, Texas, says the 2001 violations at Nuclear One had been corrected through "compensatory measures," which does not mean physical changes. The compensatory measures entailed policy changes, employee training and more frequent fire patrols, with no modifications to the cables, cable routing or the automatic fire suppression systems in those areas. Dricks says it's not easy to physically modify such a complex plant, so the NRC allows operator actions for remedial plans.
Though Arkansas Nuclear One's primary emergency system is a one-button operation - that is, a single action in the control room shuts down the core - if the front-line system is knocked out of commission for any reason, the backup system relies on a number of "operator manual actions" to safely cool off the hot reactor. This means technicians must perform dozens of separate actions, in a specific order, to shut down the core. (The Progressive reported last month that at one plant in North Carolina of a similar vintage to Arkansas Nuclear One, the NRC found this process consisted of up to 100 steps, including retrieving a stepladder, climbing seven feet up a 15-inch-wide electrical conduit, and using a screwdriver to start an auxiliary water pump).
Linda Smith is chief of plant engineering at the NRC's Arlington, Texas office. Her department carried out the fire inspection at Arkansas Nuclear One in 2001. Her inspectors felt that Nuclear One was relying too heavily on manual action in case of emergency, which is why they pursued the violation. "We didn't think their manual actions were realistic at the time," said Smith. "That's sort of a subject of ongoing debate - there's rulemaking going on right now in the NRC to address what is the most appropriate amount of manual action." The steps the plant has taken since then, both Smith and Dricks say, however, have brought itinto compliance with NRC regulations.
Under optimal conditions, writes Nuclear One spokesman Phil Fisher in response to a written query by Arkansas Times, the core can be shut down automatically "in one step and in one second." While no one with the NRC or Arkansas Nuclear One could give a specific number of actions that it would take to manually shut down the core in the event of an emergency, Smith reports that the plant has revised procedures since 2001 to make a manual shutdown much less complicated.
Figure in the worst-case scenario - failure of part or all of the automatic shutdown system, catastrophic fire in critical areas, flames, smoke, darkness, fear, confusion, maybe even radiation - and manually shutting down the core might be harder. The idea might seem far-fetched, but many have re-examined the question because al Qaeda once considered nuclear reactors as potential targets before settling on New York and Washington buildings in September 2001.
Fisher, to what he describes as "what if" scenarios, says that the plant has security forces in place to repel attackers.
Dricks has confidence in the plant operators. "These people are well trained in being able to respond to emergencies," he said. "They have to meet very rigorous qualifications and regulations. In this case here, we felt [in August 2001] that the reactions that would have been required would have been a bit too complicated. But it is acceptable under certain conditions for emergency response plans to utilize operators and people as part of the plan."