Page 96 - AERB Annual Report 2020

4.3 BASIS FOR ACCEPTABLE DOSE TO 4.4 INITIATIVES TAKEN BY AERB FOR
OCCUPATIONAL WORKERS AND DOSE REDUCTION
ENVIRONMENTAL RELEASES
(i) Review of Radiation Protection Aspects
The dose limits for exposure from ionizing during Project Stage
radiation for occupational workers and the
members of the public are prescribed by AERB in During design and commissioning stages,
its Directive No.01/2011 under Rule 15 of the it is ensured that an elaborate radiation
Atomic Energy (Radiation Protection) Rules, monitoring system consisting of area radiation
2004. These dose limits are based on the ICRP monitors, process monitors, environmental
recommendations and IAEA Safety Standards on monitors and efuent monitors is made available
Radiological Protection and are in line with the to give history, trend and instantaneous readings
international practice and standards. of the monitors for exposure control. Based on the
operating experience, many design modications
The estimated dose to the members of the for exposure control have been incorporated
public due to discharge of radioactive efuents progressively in the Indian NPPs.
from nuclear facilities at a site shall not exceed an
effective dose of 1 mSv in a year. During the year 2020, detailed review and
analysis of installed radiation monitors, their
(i) Observance of Dose Limits alarm set points with evolving phases of
operation was carried out for KAPP-3 which is
The exposure control consists of application under commissioning.
of primary dose limits, action levels such as
investigation level and operational restrictions. (ii) Operation Phase
Operational restrictions are established based on
dose, dose rate, air activity and surface Radiation protection programme during the
contamination levels etc., at workplace such that operation of NPPs is revised and approved by
the exposure of workers does not exceed the AERB. This programme comprises of
applicable dose limits. Individual exposures organisational, administrative and technical
exceeding the investigation levels are elements. ALARA measures are put in place for
investigated and reported to AERB. All cases of exposure control of the plant personnel and the
exposures exceeding the annual limits are public. AERB ensures that plant management
reviewed by AERB Committee on Excessive makes adequate review of the implementation
Exposures. and the effectiveness of the radiation protection
programme. Radiological Safety Ofcer for each
(ii) Authorised Limits of Environmental NPP is authorized by AERB to carry out
Releases/Discharge radiological safety functions.

The discharge of radioactive waste from an The environmental surveillance programme
NPP is governed by the Atomic Energy (Safe is also reviewed to evaluate the impact of
Disposal of Radioactive Wastes) Rules, 1987. It is operation of the NPP on the surrounding areas of
mandatory for each licensed nuclear facility to the plant site and ensure that efuent releases and
obtain authorization under these rules from the public exposures are below the regulatory limits.
Competent Authority for disposal of radioactive
wastes and le a return annually to AERB (iii) Collective Radiation Dose Budgeting
indicating the actual quantity of radioactive
waste discharge. Collective Dose Budget (CDB) is prepared by
each NPP annually on the basis of jobs (related to
Discharge constraints are set at a much radiation) that are likely to be executed,
lower value than the authorized limits to achieve anticipated collective dose in these jobs, collective
efuent releases at ALARA level. These discharge dose consumed in the previous years as well as
constraints are usually set at 50-65% of authorized the existing radiological conditions, benets
discharge limits taking into cognizance accrued by design improvements, identication
differences in NPP system design. The operating of lapses in previous attempt of jobs and
data shows that releases from NPPs have been a corrective actions taken etc. The aim is to optimize
small fraction of the specied release limits. the CDB through ALARA principle. AERB carries
out review of the CDB. Dose incurred in any

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AERB Annual Report 2020