Page 29 - May-June 2013
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Current
Issues in
Radiological
Protection
By Ted Lazo, OECD Nuclear Energy
Agency.
Ted Lazo
Ted Lazo holds a bachelors and Masters
degrees in Nuclear Engineering, and
a PhD in Radiation Protection. His
experience has
included work at
Three Mile Island,
contaminated DOE
sites, Brookhaven
National
Laboratory, and
French nuclear
power stations with
FRAMATOME and
EDF. Mr. Lazo is
presently with the
NEA’s Division
of Radiation
Protection and
Radioactive Waste
Management,
where he is
the Scientific
Secretariat of the
NEA’s Committee on
Radiation Protection and Public Health
(CRPPH).
Much of what is currently being
discussed in radiological protection is as
a result of the Fukushima accident. There
are many questions arising with regard
to how the experience from the accident
will affect the emergency and recovery
plans that are in place, and in particular
how such plans will be accepted, or not,
by affected stakeholders. The Nuclear
Energy Agency (NEA), in coordination
with other international organisations,
in particular the International Atomic
Energy Agency (IAEA), is investigating
these issues and will be developing
relevant technical reports over the
course of the next year or so. In addition,
however, the Fukushima accident
has brought home that occupational
exposure management at nuclear power
plants remains an important concern, in
“normal” operational
circumstances
as
well as in accident
situations. This paper
will briefly describe
some of the work
being
performed
by the NEA, more
specifically
by
the Committee on
Radiation Protection
and Public Health
(CRPPH), to learn
from this terrible
accident.
Occupational Exposure
The management of occupational
exposure has continued to improve, and
worker doses have continued to fall. The
Fukushima accident, beginning on the
11th of March 2011, has heightened the
awareness of occupational exposures
within utilities, and focused efforts on
preparedness to prevent, and if necessary
to address severe accidents. Overall,
however, the management of occupational
exposures at operating facilities has
remained good. As the following graphs
and table show, occupational exposures
have roughly been cut in half over the
past 20 years. This decrease can be seen
in the annual average dose per reactor
(Figure 1), and in Figure 1, as well as in
Figure 2, which shows the 3-year rolling
average annual exposure to reflect years
in which reactors have no outage periods.
This same information is also captured in
Table 1.
These gains in occupational exposure
have come as a result of deliberate
work management activities on the part
of reactor operators, and through the
exchange of operational experience and
dose reduction approaches. One area
of key importance to dose reduction is
source-term management. To contribute
to the exchange of experience in this
area, the NEA’s Information System
on Occupational Exposure (ISOE) is
developing a state-of-the-art report on
primary circuit water chemistry and its
effect on occupational exposure. Water
chemistry approaches in different designs
of NPPs vary in results and consequences
in terms of radiation protection
performance. The ISOE Expert Group
on Water Chemistry and Source-Term
Management (EGWC) was established
and mandated to address the experience of
various ISOE utilities with various water
chemistry regimes to explore if experience
exchange could help to improve radiation
protection performances. It is also
necessary to note that water chemistry
should not be viewed only from the
context of radiation protection issues, but
also from the context of operational and
safety issues. With these aspects in mind,
the work has been grouped into a few of
the most commonly used water chemistry
approaches (e.g. zinc injection, pH
control, iron injection, hydrogen water
chemistry, etc.) to focus the exchange
of experience. The expert group work,
which is due to be completed in 2014, is
focusing primarily on:
Description of strategies and
•
techniques aiming to limit the level
of activity in the primary coolant
(prevention of contamination);
Description of strategies and
•
techniques for the decrease of
activity in the primary coolant or
circuit decontamination (remediation
of contamination);
Nuclear Plant Journal, May-June 2013 NuclearPlantJournal.com
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