Billions of dollars’ nuclear industry's predicament?

BIER Report VII: Biologic Effects of Ionizing Radiation (BEIR) develops the most up-to-date and comprehensive risk estimates for cancer due to exposure to radiation.

The report which gives results of the life time cancer risk calculation using mathematical models from an exposure of 100 mSv dose to a typical US population. The calculations predicted one individual in 100 persons would be expected to develop solid cancer or leukemia. This can be compared with the expected 42 cancer cases that would be developed in 100 persons spontaneously due to other causes!

Risk is lower at lower exposures. Similar calculations for a lower dose of 10 mSv predict one out of 1000 exposed individual would develop cancer. However, it is very difficult due to statistical limitations, to predict reliable number of cancers at these low levels of exposure. Now, 100 mSv is the occupational dose limit for radiation workers for 5-year period, average of 20 mSv per year. The world average natural background radiation is 2.4 mSv in a year to which all of us are exposed. Average radiation exposure of the occupational workers, in general, is in the range of natural background radiation levels.

Under such situations of uncertainty how one can assume that at low doses, the cancer risk is linearly lower?  It is quite possible that the risks are lower than predicted by LNT model or non-existent or even beneficial to health. There is also no direct evidence of increased risk of non-cancer diseases at low doses.    

Now why at all assume existence of cancer risk at such low levels of radiation and impede progress of the nuclear industry worth billions of dollars? 

[The BIER VII document: Health Risks from Exposure to Low Levels of Ionizing Radiation is available from the National Academies Press, 500 Fifth Street, NW, Washington, DC 20001, 2006] 

News item in Sunday Times (Sept. 7, 2014): Cancer behind 70% deaths in India’s atomic energy hubs

The change in the cell's genetic material may occur spontaneously or be brought on by an agent that causes cancer (a carcinogen). There are hundreds of reasons such as pollution, family history, cigarette smoking, intake of alcohol, exhausts from vehicles, etc for initiation of mutation in the body. As compared to these, radiation is a weak carcinogen.

It is a well-known fact that aging is associated with a number of events at the molecular, cellular and physiologic levels in our body that influence carcinogenesis and subsequent cancer growth. It is also well documented that the incidence of malignant tumors increases progressively with age, in both animals and humans.

A clearer understanding of these events will help in predicting and scientifically explaining the incidences of cancer.

The radiation doses received by workers in most of the facilities are in the range of natural background radiation dose to which all human being are exposed. The increase, if at all true, may not be related to the small radiation doses received by the workers and the members of the public living near nuclear facilities. It is reported that majority of deaths of persons in DAE centres are caused from cancer. If this is true, department should investigate the reasons other than radiation exposure for such a trend.

Kudankulam Judgment – well delivered

There was a news item in today’s DNA: “No clear reason in the Kudankulam judgment” authored by Praful Bidwai. It is shocking to see that he is questioning the very judgment of the Supreme Court which we all hold in great esteem. It is a well-informed judgment.

The judgment is very well made asking the government to follow all the safety related recommendations of the Indian Regulatory Board, AERB. The plants are ready and the technology is well known. There are very few cases of fatality in nuclear industry as compared to any other industry. There are well studied and well established techniques for the management of radioactive wastes.

One should not forget that we are all exposed to natural background radiation from space, from the radioactivity present in earth and the air we breathe. This we cannot avoid. We also do not mind getting X-rayed or CT scanned for diagnosis of diseases. These procedures do result in giving radiation dose to us.

The number of deaths Mr. Bidwai claiming (Chernobyl and Fukushima) is only the estimates and not the actuals! People should not be misguided by these mathematically calculated numbers. Compared to this calculated numbers, one can see instant fatalities in natural events. For example, the recent US twister with the energy equivalent of 600 Hiroshima bombs, resulted in deaths, and mass destruction in Oklahoma, of the order of USD2 billion!

It is rightly pointed out that one has to pay a small price for the immense benefits one gets from the use of electricity. These small risks are ACCEPTABLE.

It is time that the anti-development groups, anti-nuclear group in particular, should stop playing with estimated number of fatalities in any development programmes and focus on something more productive and serve the humanity. 

Cancer risk estimates by WHO - Fukushima radioactivity releases

This has reference to the News Report (Fukushima Disaster raised Cancer Risk - WHO...) in Times of India dated March 1, 2013.

With all the due respect for the WHO and the team of experts who have done the risk estimations, it can be stated that: 

1. The releases from Fukushima are very much lower than the Chernobyl. 

2. The estimated number of cancer incidences from the Chernobyl releases, predicted using the similar line of calculations followed by WHO, never occurred and far from reality. 

3. The very concept of Linear No-Threshold (LNT) approach followed for the risk estimations is not  experimentally proved and hence should not be used for actual risk calculations. 

4. The LNT concept can only be used for general optimization of protection.  

5. The International Commission on Radiological Protection (ICRP), in its latest recommendations, clearly stated that: Risk factors for carcinogenesis calculated using LNT approach have a high degree of uncertainty. This is particularly so for the calculation of cancer risk by adding up of the calculated low levels of individual doses to the members of the public (which is a small fraction of the natural radiation dose received by all of us), in situations of environmental releases in accidents. This is exactly the situation encountered in Fukushima nuclear accident. 

6. The ICRP Recommendations (ICRP-103, page no. 313) is the backbone of Radiological Protection   world-wide, and it clearly states that the adding up of small estimated doses over large populations and calculating the cancer risk is using LNT approach is NOT A VALID PROCEDURE. 

Based on the above facts, it is not advised to give such a publicity to the news item, which will only harm the nuclear industry. 

For further reading pl see: 

http://healthcare.financialexpress.com/inimaging2011jul/inimaging2011july09.shtml  

Storage of Spent Nuclear Fuel, IAEA Safety Standards Series SSG-15 Subject Classification: Radioactive waste management, STI/PUB/1503, 110 pp. Language: English, Date Published: 2012.

This Safety Guide provides recommendations and guidance on the storage of spent nuclear fuel. It covers all types of storage facilities and all types of spent fuel from nuclear power plants and research reactors. It takes into consideration the longer storage periods that have become necessary owing to delays in the development of disposal facilities and the decrease in reprocessing activities. It also considers developments associated with nuclear fuel, such as higher enrichment, mixed oxide fuels and higher burn-up. Guidance is provided on all stages in the lifetime of a spent fuel storage facility, from planning through siting and design to operation and decommissioning, and in particular retrieval of spent fuel. 

Contents: 1. Introduction; 2. Protection of human health and the environment; 3. Roles and responsibilities; 4. Management system; 5. Safety case and safety assessment; 6. General safety considerations for storage of spent fuel. Appendix I: Specific safety considerations for wet or dry storage of spent fuel; Appendix II: Conditions for specific types of fuel and additional considerations; Annex: I: Short term and long term storage; Annex II: Operational and safety considerations for wet and dry spent fuel storage facilities; Annex III: Examples of sections in operating procedures for a spent fuel storage facility; Annex IV: Related publications in the IAEA Safety Standards Series; Annex V: Site conditions, processes and events for consideration in a safety assessment (external natural phenomena); Annex VI: Site conditions, processes and events for consideration in a safety assessment (external human induced phenomena); Annex VII: Postulated initiating events for consideration in a safety assessment (internal phenomena) (Source; www.iaea.org).

Stable iodine prophylaxis

Stable iodine prophylaxis is a protective measure of administration of stable iodine to block uptake and reduce accumulation of of radioactive iodine released in nuclear reactor accidents, in thyroid. The administration is done before, or promptly after, intake of radioactive iodine released in nuclear reactor accidents. Intake of radioactive iodine by inhalation begins when the radioactive cloud arrives at a location and continues during the passage of the cloud. Action to implement stable iodine prophylaxis, and thereby reduce the dose to the thyroid, will be required promptly. The decision will most probably have to be made in a situation when reliable data for calculating the potential dose to the thyroid are not available. 

Stable iodine could also be used as prophylaxis against ingested radioactive iodine from contaminated food. However, in such situations, the iodine prophylaxis will be required for a longer period of time, leading to a need for repeated doses. In such situations, food controls would be easier to implement and more effective in the long term in reducing the collective dose than stable iodine prophylaxis.

Spent Nuclear Fuel – A Waste or a Resource?

In any power plant, there is a need of fuel which needs to be burnt to generate heat which in turn is used to produce steam and ultimately to produce electricity. In fossil fuel based plants, the fuel is coal or gas. There are different types of fuels, such as heavy metal fuels like naturally occurring uranium, enriched uranium ²³⁵U, plutonium (Pu) or their appropriate mixtures can be used in nuclear reactors. The radioactive isotopes – ²³⁵U and ^239/240Pu are fissile materials, meaning that the radioisotopes can undergo fission reaction to produce energy, termed as nuclear energy. Very highly radioactive fission products (see the reaction below) are also produced in the fission reaction. The half-lives of these fission products vary from seconds to several years. In addition to the release of energy during fission reaction, the decaying fission produce in the fuel generates large amount of heat (termed as decay heat). The heat from the fuel is utilized to produce steam via suitable heat exchanger systems.

In nuclear reactors, this rate of fission reaction is controlled, by design, to ensure proper and safe utilization of the released energy.     

In the reactors, nuclear fission reaction is induced using a sub-atomic particle, neutron. For example, heavy metal, ²³⁵U absorbs a neutron in the reactor to become an unstable nucleus ²³⁶U, which splits into two lighter and highly unstable products fission products, three neutrons and a lot energy. The unstable fission products quickly decay to finally become ¹³⁷Cs (a beta-gamma emitter) and ⁹⁰Sr (a beta emitter) with half-lives of around 30 years.

The ²³⁸U isotope forms about 99.27% of natural uranium. In the nuclear reactors, due to the neutron absorption, a small percentage of the uranium isotope gets converted through nuclear reactions, to plutonium isotopes which are again good fissile materials and can be used in nuclear weapons, and as part of mixed nuclear fuel used in “breeder” reactors. The remaining portion of the spent fuel consists of depleted uranium (DU) where the percentage of fissile ²³⁵U is reduced due to the fission reaction in the reactor to below the existing level of 0.72% in natural uranium fuel.

After the useful life of the nuclear fuel in the reactor, the highly radioactive fuel is called Spent Nuclear Fuel (SNF). As such, SNF does not have further use as nuclear fuel.

In addition to the fission products, plutonium, depleted uranium, the SNF also contains minor actinides which include long-lived and relatively long-lived isotopes of neptunium (²³⁷Np), americium (²⁴¹Am and ²⁴³Am) and curium (²⁴²Cm, ²⁴⁴Cm). These are also useful radioisotopes. Efforts are underway to separate the fission product radionuclides chemically from the waste and use them as radiation sources in industrial applications of radioisotopes.   

In countries where nuclear power has a considerable share in electricity production and has adequate uranium resources, the SNF is considered as nuclear waste and is disposed of or stored safely in isolation from the biosphere.  In countries like India, where there is shortage of uranium and need plutonium as fuel for the future up-coming reactors, the SNF is the resource material which can be reprocessed chemically to separate the useful plutonium and depleted uranium from the spent fuel.  

It is reported that India now retains the right to reprocess the SNF in India, with all the safety aspects considered, from upcoming Kudankulam nuclear power plant instead of sending them away to Russia.