Order Code RS21131
Updated November 27, 2002
CRS Report for Congress
Received through the CRS Web
Nuclear Powerplants:
Vulnerability to Terrorist Attack
Carl E. Behrens
Specialist in Energy Policy
Resources, Science, and Industry Division
Summary
Protection of nuclear powerplants from terrorist attack has become a current
concern in light of the September 11 attacks. Assault by land from armed terrorists, and
the threat of crashing a hijacked airliner into a reactor, are possibilities being studied as
regulations and protection measures are reviewed. Legislation to increase security
measures and requirements, including proposals to form a federal nuclear guard force,
was introduced in the 107th Congress, but none was passed.
Nuclear powerplants have long been recognized as potential targets of terrorist
attacks, and critics have long questioned the adequacy of the measures required of nuclear
plant operators to defend against such attacks. Following the September 11 attacks on the
Pentagon and the World Trade Centers the Nuclear Regulatory Commission (NRC)
activated its Emergency Response Center and advised all plant operators to go to the
highest level of security alert, where they have since remained. NRC also began a “top-
to-bottom” review of its security requirements, and on February 26, 2002, issued “interim
compensatory security measures” to deal with the “generalized high-level threat
environment” that continues to exist for nuclear powerplants.
Current Regulations
All commercial nuclear powerplants licensed by NRC have a series of physical
barriers to accessing the operating reactor area, and are required to maintain a trained
security force to protect them. The plant sites are divided into three zones: an “owner-
controlled” buffer region, a “protected area,” and a “vital area.” Access to the protected
area is restricted to a portion of plant employees and monitored visitors, with stringent
access barriers. The vital area is further restricted, with numerous additional barriers and
access requirements. The security force is subject to stringent pre-hiring investigation and
undergoes extensive training.
Design Basis Threat. A key element in protecting nuclear plants is the
requirement that simulated terrorist attack exercises, monitored by NRC, be carried out
to test the ability of the plant operator to defend against them. The severity of attacks to
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be prepared for are specified in the form of a “design basis threat” (DBT), which has
come under attack by critics of NRC’s regulatory system. A widely expected outcome of
NRC’s “top-to-bottom” review of security regulations is a revised and expanded
definition of the DBT.
Emergency Response. After the 1979 accident at the Three Mile Island nuclear
plant near Harrisburg, PA, Congress required that all nuclear powerplants be covered by
emergency plans. NRC requires that within an approximately 10-mile Emergency
Planning Zone (EPZ) around the plant the operator must maintain warning sirens and
regularly conduct evacuation exercises monitored by NRC and the Federal Emergency
Management Agency (FEMA). In light of the increased possibility of terrorist attack that,
if successful, could result in release of radioactive material, critics have renewed calls for
expanding the EPZ to include larger population centers.
Another controversial issue regarding emergency response to a radioactive release
from a nuclear powerplant is the distribution of iodine pills. A significant component of
an accidental or terrorist release from a nuclear reactor would be a radioactive form of
iodine, which tends to concentrate in the thyroid gland of persons exposed to it. Taking
a pill containing non-radioactive iodine before exposure would prevent absorption of the
radioactive iodine. Emergency plans include distribution of iodine pills to the population
within the EPZ, which would protect from exposure to radioactive iodine, although giving
no protection against other radioactive elements in the release. Proposals to strengthen
emergency procedures often include wider stockpiling and distribution of iodine pills.
Nuclear Plant Vulnerability
Operating nuclear reactors contain large amounts of radioactive fission products
which, if dispersed, could contaminate soil and vegetation, and be ingested by humans
and animals. Human exposure at high enough levels can cause both short term illness and
death, and longer term deaths by cancer and other means.
To prevent dispersal of radioactive material, nuclear fuel and its fission products are
enclosed in metal cladding within the reactor vessel. Because the heat from the
radioactive fission products could melt the fuel-rod cladding even if the reactor was shut
down, the fuel core is kept constantly covered with circulating water. A major concern
in operating a nuclear powerplant, in addition to controlling the nuclear reaction, is
assuring that the core does not lose its coolant and “melt down” from the heat produced
by the radioactive fission products within the fuel rods.
To protect the reactor and its associated control equipment, a large “containment”
building, made of steel-reinforced concrete often many feet thick, is built over the central
part of the plant. If a reactor did lose its coolant and experience a melt-down, the
containment if intact would prevent dispersal of most of the radioactive material in the
reactor, except perhaps for some radioactive elements that are in the form of gases.
Without a breach in the containment, and without some source of dispersal energy such
as a chemical explosion or fire, the radioactive fission products that escaped from the
melting fuel cladding mostly would remain where they were. The two melt-down
accidents that have taken place in power reactors, at Three Mile Island and at Chernobyl
in the Soviet Union in 1986, illustrate this phenomenon. At Three Mile Island, loss of
coolant caused the fuel to melt, but there was no fire or explosion, and the containment

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prevented the escape of significant amounts of radioactivity. At Chernobyl, which had
no containment, a hydrogen explosion and a fierce graphite fire caused almost the entire
radioactive core to be blown into the atmosphere, where it contaminated large areas of the
surrounding countryside and was detected in smaller amounts literally around the world.
Vulnerability from Air Attack. Nuclear powerplants were designed to withstand
hurricanes, earthquakes, and other extreme events, but attacks by large airliners loaded
with fuel, such as those that crashed into the World Trade Center, were not contemplated
when design requirements were determined. NRC announced that its review of security
regulations would include a detailed engineering analysis of the effects of such a crash,
but that analysis has not yet been completed.
In light of possibility that an air attack might penetrate the containment building of
a nuclear plant, some interest groups have suggested that such an event could be followed
by a melt-down and contamination and exposure of a large numbers of persons to
escaping radioactivity. Nuclear industry spokespersons have countered by pointing out
that small, low-lying nuclear powerplants are poor targets for attack, and have argued that
penetration of the containment is unlikely, that even if it occurred it probably would not
reach the reactor vessel. They suggest that a sustained fire, such as that which melted the
structures in the World Trade Center building, would be impossible unless an attacking
plane penetrated the containment completely, including its fuel-bearing wings.
Regulatory and Legislative Proposals
Critics of NRC’s security measures have demanded both short-term regulatory
changes and legislative reforms. Among the former are calls for National Guard troops
at all nuclear sites, as well as installation of antiaircraft weapons to defend against air
attack. A taped interview shown September 10, 2002 on Arab TV station al-Jazeera,
which contains a statement that al-Quaida initially planned to include a nuclear plant in
its 2001 attack sites, intensified the calls for action. NRC Chairman Richard Meserve,
responding to news reports concerning the interview, said that although nuclear
powerplants “are clearly on potential target lists for al-Quaida,” there has been no
information suggesting that a nuclear plant has been specifically targeted. He reiterated
previous assertions of increased security and vigilance on the part of NRC and the nuclear
power industry in response to the attacks.
Expedited action to strengthen and broaden the DBT is also being called for. Critics
complain that the terrorist attack specified in the DBT is unrealistically small, and should
be increased to include a number of separate, coordinated attacks. A report issued by the
private organization Project On Government Oversight (POGO) September 12, 2002, said
that measures to increase security since the terrorist attacks have been ineffectual. It
reported that “more than 20" security guards at 13 nuclear plant sites complained in
anonymous interviews that the security forces were “under-manned, under-trained, under-
equipped, underpaid, and unsure” about the use of deadly force in protecting the facilities.
Critics also claim that nearly half of the plants tested in NRC-monitored mock
attacks failed to repel even the small forces specified in the DBT, a charge that industry
sources vigorously deny. Critics also point out that licensees are required to employ only
a minimum of five security personnel on duty per plant, which they argue is not enough

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for the job. Nuclear spokespersons respond that the actual security force for the 100-odd
nuclear reactors numbers more than 5,000, an average of 50 per reactor.
In February 2002, NRC implemented what it called “interim compensatory security
measures,” to remain in effect until the Commission either determines that the level of the
generalized threat to nuclear plants has diminished, or that other security changes are
needed following the comprehensive review of security requirements undertaken after the
September 11 attacks. Details of the specific actions required were not released, but the
NRC public announcement said they include requirements for increased patrols,
augmented security forces and capabilities, additional security posts, installation of
additional physical barriers, vehicle checks at greater stand-off distances, enhanced
coordination with law enforcement and military authorities, and more restrictive site
access controls for all personnel.
Legislation. Several bills were introduced dealing with security in nuclear
powerplants. The House on November 27, 2001, passed H.R. 2983, reauthorizing the
Price-Anderson nuclear indemnification act; included in the bill was a section on “Nuclear
Facility Threats” (Sec. 12). The act would have required NRC to identify threats to
nuclear plants, issue regulations changing the DBT to meet those threats within 270 days,
and carry out periodic force-on-force tests based on the new DBT.
More comprehensive changes in nuclear powerplant security were contained in H.R.
3382, introduced by Representative Markey. A major feature of this bill would have been
to create a federal force within the NRC to replace the private guards now carrying out the
task of defending against terrorist attack. The proposal created alarm in the nuclear
industry, and also at NRC, where Chairman Meserve declared that the current system is
satisfactory and complained that having to hire a federal force would triple the size of the
NRC and divert it from its function as an independent regulator of nuclear safety and
security. The sponsors of federalization draw an analogy to the action in the recently
passed Aviation and Transportation Security Act (P.L. 107-71) to federalize airport
security personnel, but Meserve and other critics pointed to the stringent hiring and
training requirements, the higher pay, and 90% retention rate of the nuclear security force
to refute the comparison with airport personnel.
Other provisions in the Markey bill would have required stockpiling of iodine pills
in regions around nuclear plants, and exercises by federal, state and local emergency
response personnel within a 50-mile radius of plants.
House and Senate conferees, meeting to resolve differences in comprehensive energy
policy legislation (H.R. 4), on September 12 voted to adopt language reauthorizing the
Price-Anderson act, but left out the nuclear powerplant security provisions in H.R. 2983.
Proposed amendments similar to the Markey provisions were also voted down by the
conferees. The 107th Congress adjourned sine die without the conferees reaching
agreement on H.R. 4.
Senator Reid’s Nuclear Security Act (S. 1746) as originally introduced contained
many provisions similar to those in H.R. 3382. However, Senator Reid later introduced
a substitute version of the bill, which was approved by the Senate Environment and Public
Works Committee on July 25, 2002 (S.Rept. 107-335). The substitute bill would have
appointed a task force to review security at U.S. nuclear powerplants, required the

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President to establish a federal team to coordinate protection of air, water and ground
access to nuclear powerplants, and would have given statutory authority to NRC’s
recently established Office of Nuclear Security and Incident Response.
NRC Chairman Meserve, testifying before the House Energy and Commerce
subcommittee on oversight and investigations December 5, 2001, identified several
legislative initiatives which he said would help the agency upgrade nuclear powerplant
security. One proposal would authorize guards at NRC regulated facilities to carry and
use firearms to protect property of significance to the common defense and security, a
measure he said would protect guards from state criminal prosecution for actions taken
during performance of their duties. A similar measure would counter some state laws that
preclude private guard forces from utilizing some weapons by authorizing them to possess
and use weapons comparable to those available to DOE guard forces to protect against the
DBT. Provisions similar to these were included in S. 1746 as reported by the
Environment and Public Works Committee. However, the bill was not taken up in the
Senate or the House before adjournment.

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