[ RadSafe ] " EPA Tritium Risk Plan May Force Tighter Nuclear Plant Controls "

[Franta, Jaroslav]

Comments welcome:


EPA Tritium Risk Plan May Force Tighter Nuclear Plant Controls
Energy Washington Week, Vol. 4, No. 25, 20 June 2007

EPA is considering a substantial increase in its estimates of the risks
posed by human exposure to tritium, a controversial byproduct of nuclear
power generation, in a move that could prompt nuclear regulatory agencies to
tighten their risk-based approaches for regulating radiological releases
from nuclear power plants. 

However, sources say any effort by EPA to tighten the risk estimates for
tritium would likely prompt opposition from the industry and nuclear
regulators, who fear it would complicate industry efforts to present nuclear
power as an alternative to coal-fired generation under any future climate
change regime. 

Informed sources say EPA is weighing whether to double the effectiveness
factor it assigns for tritium, a risk estimate figure used in setting
contamination and cleanup standards that represents a given radionuclide's
potential to damage the human body. EPA and other federal regulators
generally set this factor at 1.7 for tritium and similar radionuclides. 

However, recent scientific findings from the International Commission on
Radiological Protection and evidence accumulated by the National Institute
for Occupational Safety and Health (NIOSH) have led some EPA regulators to
consider increasing that factor to 2 or higher, the sources say. 

Tritium is an isotope of hydrogen that produces relatively low levels of
radiation. Nuclear power plants release tritium in water and steam
discharges. Regulators in several instances have also dealt with tritium
leaks from nuclear facilities in the form of contaminated water.
Consequently the task of estimating the health risks associated with tritium
is a highly contentious issue among nuclear experts, industry and
environmentalists. 

Observers say increasing the effectiveness factor for tritium could result
in risk assessments that suggest human exposure to tritium is more harmful,
thereby giving federal regulators grounds to tighten tritium containment and
release standards at nuclear power plants, research laboratories and places
where nuclear fuel is stored. Additionally, a key activist source says the
increased risk figures could encourage more severe federal enforcement
actions should regulators discover tritium leaking at a nuclear facility. 

Increasing the effectiveness factor for tritium would have little to no
impact on EPA's radiation standards because the risk associated with tritium
would still be within already regulated levels, which are based on
calculated doses, the sources add. Nevertheless, the move could spur
regulators in other agencies -- such as the NRC and the DOE-- to adopt a
similar risk assessment approach, the sources say. 

Sources say EPA efforts to tighten its risk estimates would likely prompt
opposition from NRC and the industry, in part because it could stifle
efforts to build as many as 27 new nuclear reactors in the United States
over the next few years. 

Nuclear industry officials are hoping for a so-called "renaissance" for
nuclear power nationwide, arguing in part that the plants provide increased
energy supplies without increasing harmful greenhouse gas emissions that
contribute to climate change. 

However, environmentalists and Democrats are calling for stricter safety and
environmental controls on the industry before new plants can be built. 

News that EPA is eyeing an increase in the tritium effectiveness factor
could bolster anti-nuclear activists and prompt opposition from NRC and
industry. 

The expected growth in the nuclear energy sector, an informed federal source
says, is one reason NRC would likely resist any effort to increase the risk
factors connected to tritium. "The other agencies would try to stop it," the
source says. "Not under this administration, it'll never make it through." 

A radiological protection expert agrees, saying such an increase in tritium
effectiveness factor could "make the NRC mad." 

An NRC source downplays the significance of increasing the effectiveness
factor for tritium, saying the agency would have to formulate its own
technical opinion on the factor before adopting it. The source also takes
issue with the suggestion that the factor could impact power plant
standards, noting that new plants tend to use the most current methods to
ensure radiation exposures remain well below regulated levels. A nuclear
industry source agrees, noting that the deliberative nature of setting
radiation standards could mean that any regulatory change may be years in
the making. 

One informed source cautions that it is "not a foregone conclusion" that
increasing the factor will lead to stricter tritium regulations because
those rules are most often based on specific dose calculations. However, an
expert with a nuclear watchdog group suggests the increased factor would
translate into tougher standards and regulators "would have to do something
to undercut that" in their risk calculations for it to not have a
significant impact. 

But despite potential efforts to block tighter risk factors for tritium, the
federal source notes that EPA is slated to begin a review of its water
contaminant limits for radionuclides in 2009. Increasing the effectiveness
factor, the source adds, could encourage agency regulators to impose
stricter maximum contaminant level (MCL) limits, which the agency also uses
to set cleanup standards, during this review. The tritium MCL is currently
set at 20,000 picocuries per liter of water, roughly 4 millirems of exposure
per year. 

EPA has already seen pressure from nuclear watchdog groups to impose
significantly stricter water standards for plutonium in the pending review. 

EPA is also in the midst of a Science Advisory Board panel review examining
the agency's risk approach to radiation that will likely prompt the agency
to adjust its risk calculations for many radionuclides. A nuclear watchdog
group has repeatedly urged the panel to increase the effectiveness factor
for tritium to 3 or higher, citing several studies arguing it should be
raised. A source with one group says the panel will soon receive formal
written comments advocating such an increase. 

The panel's most recent draft report, released Feb. 23, says tritium is
among several issues the National Academy of Sciences most recent report
evaluating radiation risks, which is the basis on the panel's work, did not
address. EPA has a "need to derive a basis for risk estimates" for it, the
report says. 

The report also suggests EPA's effectiveness factor for tritium could be
increased as the agency adopts its proposed radiation risk methods based on
the NAS report. In its discussion of the risks associated with low-energy
photons and electrons, the report says "an effectiveness factor for these
low energy radiations in the range of 2 to 2.5 seems reasonable." The report
includes the chemical symbol for tritium, 3H, among the particles that would
fall within that category. 

Additionally, tritium will likely be at issue in a June 21 meeting between
officials with the NRC and the nuclear industry focused on a voluntary
industry initiative begun last year to boost groundwater protection
standards at power plants. The initiative was prompted by concerns over
tritium leaks at several nuclear facilities. 

However, the nuclear industry contends such leaks are not dangerous to
public health and are generally contained within the facility in question.
The radiological protection expert adds that concerns over tritium leaks
would be better addressed by ensuring it is contained at a site, rather than
increasing the risk factors associated with it. The source points out that
NRC and the nuclear industry itself closely monitor tritium to ensure leaks
and other unintentional releases are prevented.

























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