COUNTRY PRESENTATION: SOUTH AFRICA RADON IN EXISTING EXPOSURE SCENARIOS 22 - 25 OCTOBER 2013 - WILCOT SPEELMAN
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COUNTRY PRESENTATION: SOUTH AFRICA
RADON IN EXISTING EXPOSURE SCENARIOS
22 – 25 OCTOBER 2013
WILCOT SPEELMANCONTENTS
• SCOPE: EXISTING EXPOSURE SCENARIOS – GSR – PART 3
• GENERIC REQUIREMENTS: EXISTING EXPOSURE SCENARIOS
• PUBLIC EXPOSURE: EXISTING EXPOSURE SCENARIOS
• OCCUPATIONAL: EXISTING EXPOSURE SCENARIOS
• EXAMPLES: OCCUPATIONAL – GOLD MINING
• EXAMPLES: PUBLIC- HISTORIC MINING ACTIVITIES
• RADON CONCENTRATION REFERENCE LEVELS - PUBLIC
• RADON CONCENTRATION REFERENCE LEVELS – OCCUPATIONAL
• CURRENT SOUTH AFRICAN LEGISLATION – RADON EXPOSURE
• CONCLUSIONS AND RECOMMENDATIONS
2SCOPE: EXISTING EXPOSURE SCENARIOS
Exposure due to natural sources, including (Focus of this Presentation):
(i) 222Rn, 220Rn
and their progeny
a) in workplaces other than those for which exposure due to other radionuclides in the
uranium or thorium decay chains is controlled as a planned exposure situation,
b) in dwellings and in other buildings with high occupancy factors for members of the
public;
(ii) Radionuclides of natural origin, regardless of activity concentration, in commodities,
including food, feed, drinking water, agricultural fertilizer and soil amendments, and
construction material, and existing residues in the environment;
(iii) Materials, other than those stated in (ii), in which the activity concentration of no
radionuclide in either the uranium or thorium decay chains exceeds 1 Bq/g or the activity
concentration of 40K does not exceed 10 Bq/g,
(iv) Exposure of aircrew and space crew to cosmic radiation.
3GENERIC REQUIREMENTS: EXISTING
EXPOSURE SCENARIOS
• Requirement 47: Responsibilities of the government specific to existing
exposure situations
The government shall ensure that existing exposure situations that have
been identified are evaluated to determine which occupational exposures
and public exposures are of concern from the point of view of radiation
protection.
4PUBLIC EXPOSURE: EXISTING EXPOSURE
SCENARIOS
• Requirement 48: Justification for protective actions and optimization of protection
and safety
The government and the regulatory body or other relevant authority shall ensure that
remedial actions and protective actions are justified and that the protection and safety
is optimized.
• Requirement 49: Responsibilities for remediation of areas with residual radioactive
material
The government shall ensure that provision is made for identifying those persons or
organizations responsible for areas with residual radioactive material, for establishing
and implementing remediation programmes and post-remediation control measures, if
appropriate, and for putting in place an appropriate strategy for radioactive waste
management.
• Requirement 50: Public exposure due to radon indoors
The government shall provide information on levels of radon indoors and the
associated health risks and, if appropriate, shall establish and implement an action
plan for controlling public exposure due to radon indoors.
5OCCUPATIONAL EXISTING EXPOSURE
SCENARIOS
Requirement 52: Exposure in workplaces
The regulatory body shall establish and enforce requirements for the protection of workers in
existing exposure situations.
Exposure due to radon in workplaces
5.27. The regulatory body or other relevant authority shall establish a strategy for protection against
exposure due to 222Rn in workplaces, including the establishment of an appropriate reference level for
222Rn. The reference level for 222Rn shall be set at a value that does not exceed an annual average
activity concentration of 222Rn of 1000 Bq/m3, with account taken of the prevailing social and economic
circumstances. (On the assumption of an equilibrium factor for 222Rn of 0.4 and an annual occupancy
rate of 2000 hours, the value of activity concentration due to 222Rn of 1000 Bq/m3 corresponds to an
annual effective dose of the order of 10 mSv).
5.28. Employers shall ensure that activity concentrations of 222Rn in workplaces are as low as
reasonably achievable below the reference level established in accordance with para. 5.27, and shall
ensure that protection is optimized.
5.29. If, despite all reasonable efforts by the employer to reduce radon levels, the activity concentration
of 222Rn in the workplace remains above the reference level established in accordance with point 5.27,
the relevant requirements for occupational exposure in planned exposure situations as
stated in Planned Exposure Scenarios shall apply.
6EXAMPLES: OCCUPATIONAL – GOLD MINING
i) ANGLOGOLD ASHANTI
a) Mining for Gold and Uranium – Conventional Mining (stoping – non mechanical)
b) Great Noligwa – trend from around 300 – 1000 Bq.m-3 (Normal range and decreasing
with environmental controls)
c) Tau Tona – trend ranging betweenEXAMPLES: PUBLIC – HISTORIC MINING
ACTIVITIES
(i) STEENKAMPSKRAAL
a) Rare Earth Mine – Lanthanides and Actinide rich + Associated NORM
b) Radon and Thoron is the main contaminants (inhalation)
c) Estimated Public Dose due to Radon of 506 Sv/a – Before Controls
d) Thoron Estimated Dose of 104 Sv/a
e) Abandoned Mine (Historically) – Possibility of mining residue used for building construction
(ii) BEAUFORT WEST
a) Historically Exploration Activities for Uranium
b) Natural outcrops and near surface deposits of uranium rich ore
c) Highest Contact Dose Rate of 10.5 Sv/h and ambient dose rate of 2.13 Sv/h – 238U identified
(Mining Area)
d) Highest Radon Activity Concentration of 323 Bq.m-3 detected.
e) Material from abandoned areas also used to construct roads (dirt) and parts of houses
(iii) EVANDER TOWN
(i) Natural background is higher than the country average
(ii) South African Average of 60 Bq.m-3, but Evander was measured at 170 Bq.m-3
8RADON CONCENTRATION REFERENCE LEVELS
- PUBLIC
Annual
Occupancy of
7000 hours
Public ICRP Dose
Equilibrium Factor
of 0.4 Exposure Conversion
300 Convention
Bq.m-3
10 mSv/a
Dose
9RADON CONCENTRATION REFERENCE LEVELS
- OCCUPATIONAL
Annual
Occupancy of
2000 hours
Occupational ICRP Dose
Equilibrium Conversion
Factor of 0.4
Exposure
1000 Bq.m-3 Convention
10 mSv/a
Dose
10CURRENT SOUTH AFRICAN LEGISLATION –
RADON EXPOSURE
NNR Act and Safety Standards and Regulatory Practices Legislation
(i) Dose Limitation (Section 3)
a) Public
b) Occupational
(ii) Regulated Actions
a) Application to Radon Exposures (Section 4.12)
b) Where Prior Safety Assessment determines a radon exposure to less than
6mSv/a,
c) Then, limited number of conditions are applicable to the authorised action
(iii) Proposed Regulations on Radiation Protection (In Progress)
a) Dedicated section for Public and Occupational Exposure due to Radon
Indoors/Workplaces
b) Public Proposal not to exceed annual average concentration of 300 Bq.m-3
c) Occupational Proposal not to exceed annual average concentration of 1000
Bq.m-3
11CONCLUSIONS AND RECOMMENDATIONS
– South Africa has a number of source material that will give rise to
Existing Exposure Scenarios to Radon in Public and Workplaces
– The source material ranges from the Mining and Mineral Processing
facilities, but also from natural occurring deposits and environs
– Discussion is still needed on whether the responsibility of existing
exposure scenarios should be remediated by government or owners
– Strategies must be set up to remediate areas of high radon areas
(caused by Mining and Mineral Processing or Abandoned Areas)
– Adopting Reference Levels for Occupational and Public is of
importance and will have implications that must be further
investigated
– Finalise process for updating Regulations to implement the Reference
Levels
12FIN - THANK YOU
Wilcot Speelman I Senior Specialist: Environment & Radiation Protection I National Nuclear Regulator
Eco Glades 2 Block G, 420 Witch Hazel Avenue, Highveld, Centurion. I PO Box 7106 Centurion, 0046
c: +27 (0) 83 744 7492 I t: +27 (0) 12 674 7102 I f:+27 (0) 86 589 0368 I e: wjspeelman@nnr.co.za I
w:www.nnr.co.za
“For the protection of persons, property & the environment against nuclear damage”
Je vous remercie tous
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