|The staff of Korea Institute of Nuclear Safety (KINS) has reviewed the draft recommendations of the ICRP and presents its views and comments as follows.
[Biological Aspects of Radiological Protection]
The new approach to estimate hereditary risks accounted two generations of human body resulted in decreased values and this reduction is agreed upon in the fact of no direct evidence that exposure of parents to radiation leads to excess heritable disease in offspring. Regarding the judgement of exclusion of the concept of Equilibrium Generation from the methodology, it should not be allowed to bring it back into consideration again in future.
The updated radiation weighting factor of protons and neutrons are welcome as they affirmatively consider the latest biological effects that have been discovered. However, frequent changes of weighting factors, for example, the neutron values are updated in ICRP 92, are leading to negative influence in the area of radiation protection as well as public trust.
Further, it is anticipated that the newly recommended tissue weighting factors will have a great impact on the dose assessment of not only internal but also external exposure. In particular, they shall be followed by calculation of new Dose Coefficients, Annual Limits on Intakes, Derived Air Concentration, and new derived and auxiliary limits including the criteria for liquid or gaseous effluents. It was specifically revealed in a questionnaire survey conducted by KINS to the non-power industries that operators experience many difficulties in applying the derived and auxiliary limits.
Therefore, it is necessary to perform simulation of the influences to estimate the resulting changes in the derived and auxiliary limits and dose coefficients when new radiation weighting factors and tissue weighting factors are recommended. Otherwise, it is probable that both the operators and the authority shall experience misunderstandings or mistrust when trials and errors occur as a result of unexpected problems later on.
Regarding the update of tissue weighting factors, certain deterioated trust of authority should be taken into account because of frequent changes. As long as allowance is permited, it is hoped that the publication of new ICRP be postponed until the foundation documents, regard to auxilary limits and dereived limits such as Annual limits on Intakes and Derived air concentraiton data, expressed in the text and the reference reports of benchmarkings or pilot tests are prepared completely.
Furthermore, examples and cases need to be provided to avoid misuse of the effective dose whose concept has been applied for protection purposes. Text needs to add warning of misuses.
With regard to the paragraph 125, we would request ICRP to clarify its position on the use of operational quantity of eye dose Hp(3) this is because the draft recommendations still maintain the equivalent dose limit to the lens of the eye.
[The system of Radiological Protection]
It is believed that the new radiation protection system which presents and emphasizes protection based on dose constraints for the single source views the radiation protection issue from a practical and reasonable perspective. Regulation based on dose limits ensures easy application and interpretation in cases of simple exposure conditions, i.e. exposure to a single source for an individual. However, given that diverse types of complex exposures are possible, utilities, business managers and regulators will inevitably face numerous difficulties in complying with the dose limits based on individual relations. Therefore, it has been assessed as desirable to emphasize source related dose constraints, especially for the case of public exposure. It seems that dose constraints can overcome the limitation of dose limit easily in that case.
The Korean regulation system mandates objective or target values similar to the dose constraints that are presented by a single source or practice, and their appropriateness is reviewed case by case in the process of the regulation although it does not specify the concept of dose constraints. Yet, it appears that sufficient reviewing and studies as to how the current legal system specifies and applies dose constraints to the general single source not based on case by case, and how and whether they may be used as effective regulatory means, will be necessary. In particular, it would take lots of effort and time among the stakeholders to fine-tune and establish the dose constraints to the single sources.
The ICRP should at least present scientific approaches to the evaluation methods for establishing constraints so that the relevant international organizations such as IAEA or OECD/NEA may suggest constarint values if the ICRP is unable to do so in view of its organizational nature.
For the three types of exposure situations mentioned by the ICRP draft recommendations, it is necessary to present specific examples or detailed classification criteria of those exposure circumstances as the division between two different circumstances, planned & emergency situation or accident vs. incident happening condition, may be obscure.
[Medical Exposure of Patients]
Regarding the articles of patient comforters and carers including families and friends, they need to be discussed in-depth and dealt in separate section other than medical exposure.
We suggest that ‘6.3 Exposure of pregnant patients’ should better be replaced with “medical exposure of pregnant women” in the publication 60.
There should be a room for setting international diagnostic reference level although ICRP cannot recommend this level. In addition, the diagnostic reference level should be evaluated periodically to take into account the development of medical science and technology.
[Exposure to Natural Sources]
Another regulation approach is seemingly necessary to regulate the NORMs when their radioactive concentration exceeds their exemption levels in wastes or byproducts, as raw materials in traditional industries - which are not related to nuclear industries - are concentrated in their processing flows. It is desirable to present recommendations on possible approaches for applying the radiation protection system to both existing (existing exposure situation) and new industries (planned situation) considering the principle of equity.
The third sentence in the paragraph 286 seems incomplete. It needs to be rephrased for a clearer meaning.
The last sentence in the paragraph 294 refers to incorrect chapter for excluded sources (Chapter 10 is that for protection of the environment). The last sentence in the paragraph 295 contains parts irrelevant to natural sources. Therefore, delete the expression “and for material in the form of a sealed source with a dose rate less than 1uSv/h at a distance of 0.1 m.”
The new recommendations are believed to have been compiled very well as they present representative examples – [(1) exposure to an individaual in normal event; (2) exposure to individuals in a nuclear reactor accident or abuse of a source; and (3) prolonged exposures in disposal of radioactive wastes] – in connection with the “potential exposures” which have so far been indicated as vulnerable based on the draft recommendations published in 2002. In particular, the ICRP provides useful information on the practical applications of the annual risk constraints of individual exposure that it reserved in its 1990 recommendations. However, we believe it is necessary to make partial revisions to reflect the problem areas expected in the actual application of the new recommendations. With regard to Risk Constraints in §317, §318, the ICRP presents Generic Risk Constraints of 2×10-4 for radiation workers and 10-5 for the members of public. However, they should be revised to express their ‘Annual Risk’ in order to maintain consistency with the previous ICRP documents and to convey more accurate meanings.
ICRP Pub. No. 60 (§128) presented that, “If the probability of occurrence of the event causing the potential exposures is fairly high, so that several such events might be expected within a year, it should be assumed that the doses resulting from the evet will certainly occurs.” However, with regard to the paragraph 307 & 319, the new recommendations do not include any specific guidelines as to the selection of Probability and Magnitude separate or combinig approaches in the actual applications. Therefore, we hope that the ICRP will present a clearer position as regards the application system of the Probability and Magnitude separate or combining approaches in the processes for handling potential exposures.
Among the radiotherapy accident examples outlined under §332, Vietnam (1992) and Thailand (2000) accidents did not take place during radioactive therapy processes. Therefore, such cases should be deleted from the Examples of Radiotherapy Accidents or the title should be changed.
The relatively shocking term of “Safety Culture” is used in §320~323 as an optimization performance means against potential exposures. In particular, it is also suspected that the §323 provisions expect safety culture-related elements like systematized safety planning in small-scale user facilities other than nuclear reactors. The small-scale user facilities would encounter much difficulties while implementing the recommendations, although “safety culture” is no longer a strange term at nuclear power plants or other large scale facilities.
[Protection of the Environment]
This chapter only contains some background material and future plans and does not provide substantial recommendations on this issue. Thus we request ICRP to postpone the inclusion of this chapter on protection of the environment in the recommendations until detailed approaches and guides are prepared.
[Implementation of the Commission's Recommendations]
It is difficult for one regulatory agency to regulate radiation protection ranging from natural radiation exposure and emergency exposure and to protection of environment. Because there are possibilities of overlapping or blank areas, or the lack of consistency in regulation, it is necessary to assign the scope of responsibilities based on the objects of radiation protection regulation and control among multiple regulatory agencies within a same country. In addition, we need to consider both radioactive and non-radioactive hazards for the safety management of same workplaces with limited regulatory resources. Therefore, to implement effectively the recommendations of ICRP, some illustrative organizational structures and regulatory approaches would be helpful for the establishement of national radiation protection system. This is expecially required for the areas such as radioactively contaminated recycled metals and NORM.
Implemetation of the assessment of doses should better be explained because changes in the radiation and tissue weighting factors and dosimetric models may require reevaluation of the dose and discontinuity in the estimation of dose may occur in some radiation industries. Although the commission recommends that the effective doses be used for prospective aspect, there are cases that need reconstruction of doses, e.g., in the compensation program for occupational diseases.
[Glossary of Key Terms and Concepts]
We also hope that the ICRP would exercise a more discreet approach as frequent changes in the definition of terms or concepts could lead to future communication problems among the stakeholders as well. For example, the formerly used term of ‘deterministic effect’ has been replaced with that of ‘tissue reaction’. Some communication breakdown may arise because of the confusion of terms and concepts despite there being no significant changes in their actual application and influences.
Regarding the text of ICRP recommendations, ambiguity of meaning of new cultural concept, highly condensed and artistic descriptions are need to be softened for the non-English-spoken countries, for example, intervention level in Para. 348 is not clearly defined and it is difficult to understand even for the radiation protection experts in Korea.