Books, television, and movies have capitalized on the public’s lack of knowledge concerning nuclear power plants to produce a myriad of scenarios involving terrorist attacks on such plants.
Perhaps it is time to take a look at the possible motives for such an attack and the security precautions required by the federal government to prevent it.
The byproduct of nuclear power plants
Each year, approximately one-quarter of the fuel in a nuclear reactor is removed. The uranium in the fuel has been depleted.
This “spent fuel” is stored “on-site” in a 40-foot deep pool of water known as the spent fuel pool. The 12-foot-long fuel rods used to generate steam in a nuclear power plant contain fuel pellets, each of which is about 3 percent fissile uranium.
Sixty-four rods are bundled together to form a fuel rod assembly. There are over 500 assemblies in each reactor. As the uranium is depleted, it is transformed into plutonium, the stuff of which nuclear bombs are made.
However, in a bomb, the plutonium is enriched to a level of 99 percent, not 3 percent, as in the spent fuel. This level of enrichment, as well as physical geometry, contributes to the impossibility of the spent fuel pool, eventually becoming a giant nuclear bomb.
The concern with spent fuel is that it will find its way into the hands of someone with the mechanical capabilities, know-how, and desire to extract and concentrate the plutonium into weapons-grade material. Another concern is the takeover of a plant by terrorists who would hold it for ransom.
By threatening to disable the safety systems with explosives and thereby create a nuclear catastrophe, the terrorists could demand any amount of money.
Another very real concern is that some fringe anti-nuclear groups would seek to intentionally damage the plant.
Security areas of nuclear power plants
A nuclear plant is divided into three areas, for purposes of security.
The RESTRICTED AREA
This area of the plant actually begins at the plant’s property line. It is restricted in that it is private property and people within it can be asked to leave and prosecuted for trespassing if they don’t.
The PROTECTED AREA
This area of the plant is protected by a double, 10-foot-high cyclone fence topped with barbed wire. The fences completely encircle the area. Between the two fences is open space, about 10 feet wide.
This open area is monitored by at least two types of motion detectors. Infrared and ultrasonic, for example. Even a bird landing in this open area creates an unusual condition of plant operation simply because it will set off an intrusion alarm, which signifies a breach of security.
The VITAL AREAS
These are areas of the plant considered vital to the safe operation of the plant. They include the control room and reactor building, as well as certain other areas.
Entry to nuclear power plants
Vehicular traffic, such as delivery trucks, enter the facility through a series of double gates in the fence. The inner gate is not opened until the outer gate is closed behind the vehicle.
The same arrangement is used for deliveries by railroad. The vehicle is escorted throughout the plant. Speed is maintained at a walk. The fear of a suicide mission to ram a truck into one of the buildings is unfounded. The plant is designed to withstand a full-speed crash of a jumbo jet with no compromise of structural integrity.
A person entering the plant must do so through one specific building. He first empties his pockets, then passes through a metal detector, similar to those found at airports. If the metal detector alarms sounds, a wand is then used to pinpoint the alarm source.
In addition to surveying with the wand, the security guard then frisks the entrant. While this is being done by one guard, another searches any containers, such as purses, lunch boxes, etc. After the metal detector, the person must pass through an explosives detector.
Upon successfully passing these barriers, the entrant approaches another security checkpoint. Here he receives his identification badge. This is a photo ID attached to a coded magnetic card. The badge is requested by number. The photograph is compared with the person requesting it. If these match, the badge is issued, and the person approaches the turnstile, which blocks the actual entrance to the plant.
Placing the magnetic card into a “card reader,”’ he then keys a multi-digit code number into the security computer via a keypad on the card reader. If all is correct, the computer allows entry through the turnstile.
There are at least two security computers in the plant; the main one and a redundant system. Not only entry onto the plant site, but entry into any vital area as well, is controlled by computer.
Two separate guards at two different consoles, one at the security center and one in the plant near the control room, keep watch over the computer. At any time, the computer can report an individual’s present location, as well as previously entered areas of the plant and how long he remained there.
The computer sounds the alarm if unauthorized entry is attempted and reports the location of the attempted infiltration. This is not limited to entry to the protected area.
Should an individual attempt to enter a vital area for which he does not have prior clearance, even though he is permitted in the plant, the computer reacts as if he were attempting to cut his way through the fence.
These are also completely different computers than those used for monitoring plant operating conditions. These computers are dedicated solely to security-related systems.
No matter what the weather conditions, day or night, everything within the protected area is bathed in light. Huge, halogen floodlights ensure that every square inch of the plant site is illuminated as brightly as it is at high noon. Lights are changed after a period of time before they burn out. Fluorescent tubes light the interior of the buildings on the site. Here too, there are no areas of the plant which are not as bright as daylight.
Every nook and cranny of the plant is under the scrutiny of independent television cameras with overlapping fields of view. Each camera has its own separate monitor, watched and controlled by security personnel.
A video recording system keeps a constant record of everything the cameras pick up. Each camera can automatically scan or be directed to a specific area. The field of view can be remotely adjusted to cover a very large area or focus in on an individual’s face.
When the computer is told by one of its many sensors that a penetration attempt is in progress, a camera or two is directed at the specified area of the perimeter. Instantly a human makes the determination that this is either an assault or a stray bird. There is essentially no activity that occurs within the confines of the double fence that is not observed, evaluated, and recorded by someone or something, somewhere.
Nuclear power plant security is provided by a contract security company.
One advantage for the security staff working at a nuclear plant is the fact that the federal government is much more actively involved in the nuclear industry than in other industries. As a result, there is strict compliance with labor laws.
Certain assignments within the plant call for the guard to carry a firearm, others do not.
The armed security guards must re-qualify at least annually with the weapons at their disposal. The qualifications are stringent. The guard must score high on a combat shooting range. All guards must pass a regularly administered agility test to retain their jobs.
Prior to being granted entry to a nuclear plant, all employees, guards included, must attend a “badging class” that teaches basic principles of radiation protection, measurements, and federal laws regarding nuclear work. They are also taught to “dress out” in anti-contamination clothing. At the end of the course, students must pass both a written and practical examination of the material covered.
Related reading: Decontamination Procedures for Biological and Chemical Agents
Security personnel in a nuclear power plant patrol sensitive areas of the plant, on foot. They are also responsible for monitoring the security computers’ consoles, and the surveillance equipment.
Guards are posted on the roofs of buildings, temporarily open access hatches throughout the plant, and other areas that can be considered risks to plant safety or security.
An armed guard stands watch from above and outside the control room. Positions such as this and the computer consoles often require the guards to be sealed into the room using a door that can only be opened from the inside or using the watch commander’s key.
Their only contact with the outside is a sheet of bulletproof glass, their communications systems, and strategically placed gun slits.
Each guard is issued a walkie-talkie, and just like routine street patrol, must respond appropriately to time and communications checks. The plant also has, on-site, a well-equipped arms room. Here, under strict security, are automatic weapons, shotguns, handguns, protective masks, and riot control agents, among other things.
Not only is the amount and types of equipment amazing, but so is the fact that civilian security guards are well trained in their correct use, and quite capable of using them effectively.
If for some reason, the control room becomes uninhabitable or should someone with the proper access become mentally unbalanced, the reactor must be shut down. Provision has been made for this.
In another area of the plant is a console known as the remote shutdown panel. It must be activated using a key, stored separately. Another key opens the cabinet back, where SOPs, manuals, etc., relating to its use, are kept. After activating the panel, a reactor operator can safely shut the reactor down.
Shutting down the reactor during a crisis
The use of the remote shutdown panel does not, in any way, sacrifice or jeopardize plant or public safety. It does not damage the reactor or any of the components, control, or otherwise. It simply inserts the control rods into the reactor core to stop the nuclear chain reaction. It is the same procedure as is ordinarily done from the control room. It is just done from another location in the plant.
To understand how the last-ditch, mechanical safeguard works, it is necessary to know a little something about nuclear power and how the reactor works. A nuclear chain reaction occurs when a neutron is absorbed by the nucleus of a uranium atom.
The absorbing nucleus then begins to fall apart, emitting 2.5 neutrons, which are then captured by still other nuclei and so on.
When the number of neutrons being emitted exactly equals the number of neutrons required to sustain this chain reaction, the reactor is said to be “critical.”
Between the fuel bundles, we mentioned earlier are control rods. These are rods of a non-fissile material which absorbs neutrons. By absorbing neutrons, the control rods limit the number of neutrons available to sustain the chain reaction.
Controlling the rate of reaction then is accomplished by physically inserting or removing control rods from the reactor core. The control rods are moved by varying the hydraulic pressure within a hydraulic control unit (HCU). By decreasing the pressure on the reactor side of the unit, the rod is inserted. By increasing the pressure on the reactor side, the rod is withdrawn from the core.
There is a maze of plumbing that keeps all these pressures equal when the control rod movement is not desired. There is one short (about 1 foot long) series of copper fittings midway between the HCUs located on each side of the reactor. If this series of fittings is damaged, it bleeds pressure off the reactor side of all the HCUs, simultaneously.
This shift in pressure will immediately result in all the control rods being moved fully into the core, thus shutting the reactor down. This series of fittings is one of the first things shown to a new member of the operations staff. If, for some reason, the remote shutdown panel is disabled, vigorously striking this series of fittings with a wrench, hammer, etc. will break the fittings, thus shutting the reactor down. It is a last resort assurance that shutdown can be achieved from outside the control room. It also ensures that the rods cannot be moved until a great deal of work is done to return the system to full operation.
Bear in mind, these are not considered emergency systems as far as day-to-day plant operations are concerned. They are merely adjuncts to prevent a catastrophe should the security measures fail.
Fence, barbed wire, motion detectors, metal detectors, explosive detectors, security cameras, floodlights, magnetic card readers, photo IDs, computers, and armed guards. Most industries utilize a maximum of a combination of three of the above measures to ensure security, and they have few problems. A nuclear power plant utilizes all of the above, with backup systems.
As almost anyone will admit, no amount of protection can keep an individual absolutely safe from assassination, if the assassin is willing to sacrifice his own life. So it is with a nuclear plant. No amount of security measures can absolutely prevent a breach of security. But it would take a relatively large number of people willing to sacrifice their lives, and that’s just to breach security.
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