13.1.9 Impact of Radioactivity on Environment
Radioactive exposure has varied degrees of impact when it comes to environment
and public health. The international community of nuclear experts set up bars to
measure the scale of radioactivity and based on its impacts to environment. The
international nuclear and radiological event scale (INES) which was brought into
force in 1990 by International Atomic Energy Agency (IAEA) and Organization for
Economic Co-operation and Development Nuclear Agency (OECD/NEA) had made
seven levels of radiological exposures. Levels 1–4 are termed as incidents, whereas
levels 5–7 are considered as accidents. The evaluation is on the amount of dosages
people received and the number of people involved or the amount released into the
environment.
Level 1 is considered as anomaly wherein a member of public community is
overexposed to a radioactive source more than its expected statutory annual limit or a
radioactive source was picked up or minor defects in safety systems in a facility
containing radioactive substances.
Level 2 is overexposure more than 10 mSv (millisievert) to a person or a worker
working in a radioactive facility. In case of radioactive facility, radiation level
reaching more than 50 mSv per hour or contamination in the facility is also
considered as level 2 risk.
Level 3 which is also termed as serious incident involves overexposures to
workers more than ten times of its statutory annual limits or non-lethal burns or
inflammation from radiation. Exposure more than 1 Sv/h or unexpected severe
contaminations in the facility are also this level of threat. Any accidents near a
nuclear power plant or any radioactive materials stolen or lost or misdelivered also
come under this level.
Level 4 or an accident with consequences involves death of one individual due to
radiation. It encompasses minor exposure of radioactive material unlikely to have a
need of implementing countermeasures except for food sector which requires control
measures. Damage to core structure or fuel melting which if results in release of
0.1% of core material or exposure of significant amount of radioactivity which can
have significant impact on public health falls under this level.
Level 5 or an accident with broader consequences involves several deaths due to
radiation and requires implementation of countermeasures. This level also deals with
greater damage to reactor core which may result in exposure of large amount of
radioactivity within the premises of an installation.
Level 6 also known as serious accidents involves release of significant amount of
radioactive material from a radioactive source or installation. It requires planned
countermeasures to control radiotoxicity of environment.
Level 7 or major accidents can be defined as major release of radioactivity from a
source or installation with broader negative consequences on public health and
environment. It requires planned and extended countermeasures to mitigate its
radiotoxicity (Ojovan et al. 2019).
336
U. K. Vandana et al.
Radioactive exposure has varied degrees of impact when it comes to environment
and public health. The international community of nuclear experts set up bars to
measure the scale of radioactivity and based on its impacts to environment. The
international nuclear and radiological event scale (INES) which was brought into
force in 1990 by International Atomic Energy Agency (IAEA) and Organization for
Economic Co-operation and Development Nuclear Agency (OECD/NEA) had made
seven levels of radiological exposures. Levels 1–4 are termed as incidents, whereas
levels 5–7 are considered as accidents. The evaluation is on the amount of dosages
people received and the number of people involved or the amount released into the
environment.
Level 1 is considered as anomaly wherein a member of public community is
overexposed to a radioactive source more than its expected statutory annual limit or a
radioactive source was picked up or minor defects in safety systems in a facility
containing radioactive substances.
Level 2 is overexposure more than 10 mSv (millisievert) to a person or a worker
working in a radioactive facility. In case of radioactive facility, radiation level
reaching more than 50 mSv per hour or contamination in the facility is also
considered as level 2 risk.
Level 3 which is also termed as serious incident involves overexposures to
workers more than ten times of its statutory annual limits or non-lethal burns or
inflammation from radiation. Exposure more than 1 Sv/h or unexpected severe
contaminations in the facility are also this level of threat. Any accidents near a
nuclear power plant or any radioactive materials stolen or lost or misdelivered also
come under this level.
Level 4 or an accident with consequences involves death of one individual due to
radiation. It encompasses minor exposure of radioactive material unlikely to have a
need of implementing countermeasures except for food sector which requires control
measures. Damage to core structure or fuel melting which if results in release of
0.1% of core material or exposure of significant amount of radioactivity which can
have significant impact on public health falls under this level.
Level 5 or an accident with broader consequences involves several deaths due to
radiation and requires implementation of countermeasures. This level also deals with
greater damage to reactor core which may result in exposure of large amount of
radioactivity within the premises of an installation.
Level 6 also known as serious accidents involves release of significant amount of
radioactive material from a radioactive source or installation. It requires planned
countermeasures to control radiotoxicity of environment.
Level 7 or major accidents can be defined as major release of radioactivity from a
source or installation with broader negative consequences on public health and
environment. It requires planned and extended countermeasures to mitigate its
radiotoxicity (Ojovan et al. 2019).
336
U. K. Vandana et al.