Speaker
Mr
Rogerio Gomes
(Brazilian Nuclear Energy Commission, Brazil)
Description
**BACKGROUND**
Accidents occurring in irradiation facilities have demonstrated that
these facilities have safety-critical systems, which should be
designed to meet proper safety requirements. The IAEA’s publication
SSG 8 provide specific and practical recommendations on the safe
design and operation of irradiations facilities, for use by operating
organizations, the designers of these facilities and by regulatory
bodies. The first industrial irradiation facility in operation in
Brazil was designed in the ’70s. Since then, minor modifications and
upgrades, as sensors replacement, have been introduced in order to
reduce the technological gap in the control and safety systems,
however, in the case of safety systems in irradiation facilities, the
requirements concerning safety and reliability are of ultimate
importance.
**METHODOLOGY**
This work evaluates the adequacy of existing safety
systems and their sensors at Brazilian irradiation facilities, taking
into account the recommended IAEA’s design requirements.
The study is based on an assessment of the licencing process of
irradiation facilities, as well as the experience of regulatory
inspections in these facilities. It was also taken into account the
knowledge, concepts and solutions developed to upgrade existing
safety system in facilities throughout the world.
**RESULTS**
Irradiation facilities can be defined on the basis of its design and,
in particular, the accessibility and shielding of the radioactive
source. The Brazil facilities can be categorized into
9 panoramic $\gamma$ irradiators (4 dry and 5 wet storage) and
4 panoramic irradiation facilities using generators.
Notable findings arising from this study include: a) Some sensors are
not interlocked with the irradiator central controls unit, thus they
not act automatically when a predetermined value is exceeded, this
condition is normally observed, basically, on the radiation monitor of
the water treatment system and on the fire protection system; b) In
older irradiators the seismic detector is not installed; c) Redundant
systems in the personnel access door can be improved, using pressure
mats combined with optoelectronic barriers.
Additionally, it was considered if the irradiation facility can be
operated only if all safety systems are in place and functioning.
**CONCLUSION**
It was carried out a diagnosis of the “state of the art” of safety
systems of Brazilian industrial irradiators, taking into account the
national regulations and the latest IAEA´s recommendations.
Some sensors of safety systems in oldest Brazilian irradiators can be
improved, basically for automatic actuation, thus the upgrade of
control systems in irradiator facilities would use the advances in
computer technology, old control units based on relay logic should be
replaced with a new one based on redundant programmable logic
controllers, however, it should be emphasized that the operating
organization should obtain the approval of the regulatory authority
before implementing any modifications on the irradiator that may have
significant implications for radiation protection.
| Country/Organization invited to participate | Brazil |
|---|
Primary author
Mr
Rogerio Gomes
(Brazilian Nuclear Energy Commission, Brazil)
Co-authors
Mr
Evaldo Luiz Costa
(Brazilian Nuclear Energy Commission, Brazil)
Mr
Joana D'Arc Ramos Lopes Gomes
(Brazilian Nuclear Energy Commission, Brazil)
Mr
Mara Lucia Costa
(Brazilian Nuclear Energy Commission, Brazil)
Mr
Zieli Thomé
(Militar Institute of Engineering, Brazil)
