A practice case of monitoring waste resin clearance in a nuclear power plant / 中国辐射卫生

Objective To establishment a process of monitoring waste resin clearance in nuclear power plants, and to meet clearance requirements and simplify the monitoring work. Methods In accordance with the requirements specified in current laws, regulations, and standards in China, as well as the practice of slightly polluted waste resins generated during the operation of nuclear power plants, in-depth discussion was conducted on sampling methods, sample uniformity and representativeness tests, radiation monitoring contents and methods, and simplified monitoring processes, in order to accurately monitor the radionuclide activity of waste resins to be cleared. Results A process was established to monitor waste resin clearance in nuclear power plants. A total of 55 barrels of waste resins were cleared and the radiation levels met the requirements. Conclusion An effective clearance process can facilitate the sampling of representative resins, improve the accuracy of monitoring data, differentiate radioactive waste from cleared waste, and simplify the monitoring process. Our results provide a basis and reference for future waste resin clearance.

Terrestrial gamma radiation level around Shidaowan nuclear power plant, China and influencing factors / 中国辐射卫生

@#<b>Objective</b> To monitor the cumulative terrestrial γ radiation dose around Shidaowan nuclear power plant, Shandong, China before operation, to analyze the dose levels and influencing factors, and to estimate the annual effective dose to local residents. <b>Methods</b> Fifty-six monitoring sites were selected within 30 km around the nuclear power plant. The environmental γ radiation dose was measured by the thermoluminescence dosimeter monitoring method. The γ radiation dose levels were investigated for 369 days in four monitoring periods (January 16 to April 14, April 15 to July 20, July 21 to October 21, 2021, and October 22, 2021 to January 20, 2022 for periods I to IV, respectively). Relations between γ radiation and monitoring time, altitude, distance from the nuclear power plant were analyzed, and the annual effective dose of terrestrial γ radiation to residents was estimated to reflect the background terrestrial γ radiation level in the area. <b>Results</b> The average values of terrestrial γ radiation dose rate in the four monitoring periods in the area were (76.196 ± 3.366), (81.773 ± 6.144), (93.554 ± 7.449), and (97.604 ± 9.396) nGy/h, respectively, and the terrestrial γ radiation dose rate in the whole year was (87.282 ± 6.589) nGy/h. The effective dose to residents was 0.428 mSv. The terrestrial γ radiation level was high from July 2021 to January 2022. There was no significant difference in the γ radiation dose rate at the monitoring sites with different distance from the nuclear power plant. No impact upon the terrestrial γ radiation dose by the altitude was observed in this study. <b>Conclusion</b> The terrestrial γ radiation level around Shidaowan nuclear power plant in 2021 was at the background level.

Analysis of gross radioactivity levels in drinking water around Shidao Bay Nuclear Power Plant, 2018-2021 / 中国辐射卫生

Objective To investigate the gross alpha and gross beta radioactivity levels in drinking water around Shidao Bay Nuclear Power Plant before its operation. Methods Ten sampling sites were set up within 30 km of Shidao Bay Nuclear Power Plant. From 2018 to 2021, samples were collected during the dry season and wet season each year and were tested in a laboratory according to Standard examination methods for drinking water—radiological parameters (GB/T 5750.13—2006). Results From 2018 to 2021, the gross alpha radioactivity in drinking water within 30 km of Shidao Bay Nuclear Power Plant was within the range of about 0.004-0.420 Bq/L, which does not exceed the guided gross alpha radioactivity specified in the National Standard; from 2018 to 2021, the gross beta radioactivity level was about 0.008-1.050 Bq/L. In 2018, the gross beta radioactivity at the sampling site 4.7 km from the Nuclear Power Plant exceeded the guided level specified in the National Standards for Drinking Water Quality (GB 5749—2006), but it fell within the guided level in a repeat laboratory test after deducting the effect of 40K on the gross beta radioactivity. Conclusion After deducting the effect of 40K on the gross beta radioactivity, the gross alpha and gross beta radioactivity levels in drinking water within 30 km of Shidao Bay Nuclear Power Plant are within the guided levels specified in the National Standards.

The radioactivity levels of food and the dose in residents due to food intake around Shidaowan Nuclear Power Plant / 中国辐射卫生

Objective To analyze the radionuclide levels in food and the committed effective dose due to food intake in residents around the Shidaowan Nuclear Power Plant (SNPP). Methods Daily food samples were collected within 30 km radius around the nuclear power plant in 2019—2022. The radioactivity levels before and after the operation of SNPP were determined. The data were combined with the dietary consumption of residents in Shandong province, China to estimate the committed effective dose. Results The radionuclides 238U, 232Th, 226Ra, and 40K in food were at normal background levels, and the average radioactivity was (0.062 ± 0.004), (0.121 ± 0.007), (0.162 ± 0.010), and (92.4 ± 5.5) Bq/kg fresh weight. Trace 137Cs and 90Sr were detected in some food samples and the average radioactivity was (0.047 ± 0.003) and (0.193 ± 0.200) Bq/kg fresh weight. The levels of radionuclides did not increase after the operation of SNPP compared with that before operation. The estimated committed effective dose in residents due to food intake was 0.205 mSv. Conclusion The radioactivity of food in the area around SNPP shows no difference before and after operation, and the dose burden is low in local residents.

Radioactivity in marine organisms around Qinshan Nuclear Power Plant / 中国辐射卫生

@#<b>Objective</b> To determine the radioactive enrichment level in marine biological media around Qinshan Nuclear Power Plant and to evaluate the impact of effluent on marine biological media in the surrounding sea area based on the discharge of effluent from the nuclear power plant over the years and the monitoring level of surrounding marine media. <b>Methods</b> The monitoring data of ³H, ¹⁴C, ⁹⁰Sr, ¹³⁷Cs, and ^110mAg in the environmental media monitored in Qinshan Nuclear Power Plant from 2008 to 2017 were collected, and the data were processed and analyzed by IBM SPSS Statistics 26. <b>Results</b> The activity concentrations of tritium in mullet and oyster in the sea area around Qinshan Nuclear Power Plant were 0.5-2.9 Bq/kg and 0.55-8.2 Bq/kg, respectively, and the activity concentrations of tritium in both increased generally under the influence of effluent from the nuclear power plant. The activity concentrations of ¹⁴C, ¹³⁷Cs, and ⁹⁰Sr in the monitored organisms were lower than the background values. The results of correlation analysis showed that the effluent from the nuclear power plant had almost no effect on ¹⁴C. The activity level of ^110mAg decreased significantly year by year in oyster, and remained below the background level in mullet. <b>Conclusion</b> Qinshan Nuclear Power Plant is the longest operating nuclear power plant in mainland China. Most of the nuclides in biological media in the surrounding sea area are lower than the background levels, and the effluents from the nuclear power plant have little influence on marine biological media in the surrounding sea area.

Reducing the risks of nuclear war - the role of health professionals

@#In January, 2023, the Science and Security Board of the Bulletin of the Atomic Scientists moved the hands of the Doomsday Clock forward to 90’s before midnight, reflecting the growing risk of nuclear war.1 In August, 2022, the UN Secretary-General António Guterres warned that the world is now in “a time of nuclear danger not seen since the height of the Cold War.2 The danger has been underlined by growing tensions between many nuclear armed states.1,3 As editors of health and medical journals worldwide, we call on health professionals to alert the public and our leaders to this major danger to public health and the essential life support systems of the planet—and urge action to prevent it.

Time to treat the climate and nature crisis as one indivisible Global Health Emergency

@#Over 200 health journals call on the United Nations, political leaders, and health professionals to recognise that climate change and biodiversity loss are one indivisible crisis and must be tackled together to preserve health and avoid catastrophe. This overall environmental crisis is now so severe as to be a global health emergency.

On the brink: The climate and nature crisis and risks of nuclear war

@#The Russian military invasion of Ukraine on February 24, 2022, and Hamas’ terror attack on Israel on October 7, 2023, signaled the beginning of two of the most recent wars to make international headlines. To date, over 110 armed conflicts are taking place: over 45 in the Middle East and North Africa (Cyprus, Egypt, Iraq, Israel, Libya, Morocco, Palestine, Syria, Turkey, Yemen, Western Sahara); over 35 in Africa (Burkina Faso, Cameroon, the Central African Republic, the Democratic Republic of the Congo, Ethiopia, Mali, Mozambique, Nigeria, Senegal, Somalia, South Sudan, Sudan); 21 in Asia (Afghanistan, India, Myanmar, Pakistan, the Philippines); seven in Europe (Russia, Ukraine, Moldova, Georgia, Armenia, Azerbaijan); and six in Latin America (three each in Mexico and Colombia); with two more international armed conflicts (between India and Pakistan, and between India and China) in Asia.1 This list does not even include such problematic situations as those involving China and the South East Asia region. As though these situations of armed violence were not enough, mankind has already passed or is on the verge of passing several climate tipping points – a recent review lists nine Global core tipping elements (and their tipping points) - the Greenland Ice Sheet (collapse); West Antarctic Ice Sheet (collapse); Labrador-Irminger Seas / SPG Convection (collapse); East Antarctic Subglacial Basins (collapse); Amazon Rainforest (dieback); Boreal Permafrost (collapse); Atlantic M.O. Circulation (collapse); Arctic Winter Sea Ice (collapse); and East Antarctic Ice Sheet (collapse); and seven Regional impact tipping elements (and their tipping points) – Low-latitude Coral Reefs (die-off); Boreal Permafrost (abrupt thaw); Barents Sea Ice (abrupt loss); Mountain Glaciers (loss); Sahel and W. African Monsoon (greening); Boreal Forest (southern dieback); and Boreal Forest (northern expansion).2 Closer to home, how can we forget the disaster and devastation wrought by Super Typhoon Haiyan (Yolanda) 10 years ago to date? Whether international or non-international, armed conflicts raise the risk of nuclear war. Russia has already “rehearsed its ability to deliver a ‘massive’ nuclear strike,” conducting “practical launches of ballistic and cruise missiles,” and stationed a first batch of tactical nuclear weapons in Belarus,3 and the possibility of nuclear escalation in Ukraine cannot be overestimated.4 Meanwhile, in a rare public announcement, the U.S. Central Command revealed that an Ohio- class submarine (560 feet long, 18,750 tons submerged and carrying as many as 154 Tomahawk cruise missiles) had arrived in the Middle East on November 5, 2023.5 Indeed, “the danger is great and growing,” as “any use of nuclear weapons would be catastrophic for humanity.”

Analysis of causes and countermeasures against marine organisms blocking event at cold source intake of coastal nuclear power plant / 中华放射医学与防护杂志

The cold source system of a nuclear power plant, as important part of a nuclear power project, is of great significance to guarantee the safe operation of a nuclear power plant. In recent years, there have been some cases of marine organism blockage at cold source intake at coastal nuclear power plants in China, which has adversely affected the safety and economy of nuclear power plants. According to the research result of cold source safety in coastal nuclear power plants in China and in compliance with the requirements of nuclear safety regulatory control and the engineering practice experience, the causes of, and countermeasures against, marine organism blockage at cold source intake are analyzed to further improve the safety and economy of nuclear power plants.

Investigation on radionuclide deposition during primary loop overhaul at a nuclear power plant / 中华放射医学与防护杂志

Objective:To investigate radionuclide deposition in the systems related to the primary loop during the overhaul and refueling at a nuclear power plant.Methods:The radionuclides deposited in the main piping system, the primary loop coolant purification system, the volume and boron control system, the waste heat export system, and the inner wall of pipe in boron-containing water system were measured by using the low and medium radiation field high-purity germanium (HPGe) in-situ γ source term measurement system, the strong radiation field cadmium zinc telluride (CZT) in- situ γ source term measurement system, and the portable radiation monitoring instrument Radiagem-2000. Results:The result had shown that the major radionuclides deposited in the systems related to primary loop were mainly 58Co, 60Co, 95Nb, 95Zr, 51Cr, 124Sb, 54Mn, 110Ag *, 59Fe, and those with higher deposition were 60Co, 58Co, 124Sb, 95Zr. Of them, the largest deposition was 60Co up to 21 200 Bq/cm 2 in extra strong pipe below the safety valve, 58Co up to 8 480 Bq/cm 2 in the pipeline of hot section in the state of full water in the main pipeline. 124Sb was 4 910 Bq/cm 2 in pipeline before the filter of the primary loop purification system and 4 680 Bq/cm 2 in the chemical capacity drainage pipeline, respectively, and 95 Zr was 2 500 Bq/cm 2 in the pipeline of hot section in the state of full water in the main pipeline. The radionuclides deposited, after the filter of the purification system, in the pipe upstream of the boron-containing pump were significantly lower than those in other systems. Conclusions:The types of radionuclides in the systems associated with primary loop at a nuclear power plant are basically identical, but their amount deposited varies greatly. Attention should be paid to the removal of radionuclides in primary loop through the filter of purification system.

Investigation of gross α and β radioactivity levels in foods around Fuqing nuclear power plant site / 中华放射医学与防护杂志

Objective:To ascertain the activity concentration of gross α and β in foods around Fuqing nuclear power plant (NPP) site.Methods:Totally 167 food samples of 25 kinds within 6 categories were collected from the surveillance areas and control areas around Fuqing NPP site. The total radioactivity was analyzed using the food samples. Paired rank sum test was used to determine the influence of the operation of Fuqing NPP on the total radioactivity in foods in surrounding areas. The multiple local rank sum test was used to assess the difference in total radioactivity in different types of foods.Results:The average gross α in poultry meat, vegetables, crops, aquatic products, milk and tea was 0.65, 1.96, 1.41, 3.80, 1.33, 7.67 Bq/kg in surveillance areas and 0.56, 3.24, 2.04, 3.70, 2.24, 9.05 Bq/kg in reference areas, respectively, around Fuqing NPP site. The average gross β (subtracting 40K) in poultry meat, vegetables, crops, aquatic products, milk and tea was 7.0, 10.5, 6.1, 23.5, 24.7, 8.6 Bq/kg in surveillance areas and 7.4, 8.3, 14.5, 22.1, 21.3, 11.0 Bq/kg in reference areas, respectively, around Fuqing NPP site. The Wilcoxon paired rank test showed that there was no significant difference in the gross α and β in foods between surveillance and reference areas around Fuqing NPP site ( P>0.05). The Kruskal-Wallis H test showed that the radioactivity of gross α and β in different foods was statistically significant ( χ2=23.325, 13.918, P<0.05). Conclusions:The increase was not found in total radioactivity in the surrounding foods since the operation of Fuqing NPP in 2015.

Organization and thinking of provincial-level on-sit and off-sit joint exercises for nuclear emergency / 中国辐射卫生

By reviewing the organization and implementation of “Hongsha-2021” Guangxi nuclear emergency joint exercises, this article summarizes the experience in the organization process and puts forward some thoughts and suggestions in order to improve the depth of provincial-level on-site and off-site joint exercises for nuclear emergency at nuclear power plants and further enhance the emergency response capacity of nuclear emergency organizations at all levels.

Analysis of occupational health examination of workers in a nuclear power plant in Guangdong, China / 中国辐射卫生

@#<b>Objective</b> To analyze the abnormality of radiation damage sensitive indices in radiation workers after operation of a third-generation nuclear power plant in Guangdong Province, China, and to provide a basis for promoting the occupational health management of radiation workers. <b>Methods</b> A two-way cohort study (2019—2021) was conducted to compare the radiation sensitive indices of occupational health examination in the exposed group (453 subjects) and the control group (160 subjects). <b>Results</b> In 2021, the free triiodothyronine (FT3) level of the exposed group was significantly higher than that of the control group [(5.57 ± 0.56) pmol/L <i>vs</i> (5.42 ± 0.60) pmol/L, <i> t</i> = 0.59, <i>P</i> < 0.05]. From 2019 to 2021, the exposed group showed significant changes in the average levels of platelet, hemoglobin, FT3, free thyroxine (FT4), and thyroid-stimulating hormone (<i>P</i> < 0.05); FT3 and FT4 first increased and then decreased, while TSH decreased continuously. <b>Conclusion</b> Long-term exposure to low-dose ionizing radiation from nuclear power plants can affect the platelet, hemoglobin, FT3, FT4, and thyroid-stimulating hormone of radiation workers, and the effect is relatively prominent on thyroid function by causing a tendency to hypothyroidism.

Improvement and application of radiation work permit software in nuclear power plants / 中国辐射卫生

Objective To improve the efficiency of radiation work preparation, promote the comprehensive and whole-process control of radiation risk, strengthen the accumulation of experience feedback data, and improve the timeliness of approval. Methods According to the application of radiation work permits in Tianwan Nuclear Power Plant and other nuclear power plants, the radiation work permit software in Tianwan Nuclear Power Plant was improved in terms of work order connection, examination and approval process integration, approval of radiation work at different levels, unification of level classification standard, radiation risk database establishment and maintenance, and closed loop management and mobile approval of radiation work permit. Results A radiation work permit software for nuclear power plant was developed according to the requirement of radiation risk control. Conclusion The radiation work permit software effectively improves the radiation work regarding work preparation efficiency, risk control, experience feedback data accumulation, and timeliness of approval. Subsequently, information transmission efficiency and experience sharing can be improved through connection and communication with other software in nuclear power plants.

Public communication in the recovery process after the Fukushima Daiichi Nuclear Power Plant accident / 中国辐射卫生

The Fukushima Daiichi Nuclear Power Plant accident in Japan resulted in the release of large amounts of radioactive substances into the surrounding environment and caused contamination. In the accident recovery process, Japan had made great efforts in public communication, including the government’s promotion of organization and planning the popularization and publicity of scientific knowledge in various forms, multi-channel information disclosure, and all-round communication and exchange, which can provide a reference for the development of relevant work in China. The nuclear-related public communication work in China can get four enlightenments. Firstly, the public communication system should be improved, and corresponding policies and mechanisms should be clarified. Secondly the popularization of nuclear science knowledge should be taken as the foundation for early and long-term development. Thirdly, the operators of nuclear facilities shall disclose relevant information according to the law and confront the curiosity or doubts of the public. Finally, multi-channel, multi-level and multi-frequency exchanges and interactions should be conducted to seek unity of understanding and balance of interests between the two sides.

Psychological crisis intervention for emergency rescue workers during major nuclear power plant accident / 中国辐射卫生

The nuclear accidents in Chernobyl and Fukushima had great impacts on the mental health of emergency rescue workers, who experienced a series of psychological problems shared by the accident victims. This paper analyzes the psychological symptoms suffered by emergency rescue workers in Chernobyl and Fukushima nuclear accidents, as well as the psychological crisis interventions for rescue personnel involved in major natural disasters and pandemics. Based on the special situations faced by emergency rescue workers in nuclear accidents, we propose psychological crisis interventions for rescue personnel during major nuclear accidents. These interventions include mental health assessment and training before accident, psychological assistance, self-adjustment, and crisis intervention during accident, and long-term psychological assistance after accident. The psychological impacts on emergency rescue workers can be reduced by effective psychological interventions.

Application of thermoluminescence dosimeter in environmental monitoring of nuclear power plant / 中国辐射卫生

Objective To investigate the effect of gaseous effluent from the six generator sets on the radiation level of the surrounding terrestrial environment in Daya Bay Nuclear Power Base after the operation of Ling’ao Nuclear Power plant. Methods The radiation level in the peripheral environment of the Base was monitored using the thermoluminescence dosimeter （TLD）. Twenty-five monitoring sites were set around the Base to investigate the variation of radiation level over a long period of time by collecting the TLDs every three months. Results From 2011 to 2020, the annual γ dose rate of the 25 sites ranged from 76.7 to 207.1 nGy/h, with an average value of (123.3 ± 5.7) nGy/h and a relative deviation of 2%-12%. The TLD monitoring and instantaneous measuring results of γ dose rate were consistent with the survey of the State Environmental Protection Administration in the 20th century and the baseline level prior to the operation of the nuclear power plant. Conclusion There are great differences in natural environmental radiation level across the TLD monitoring sites. The overall environmental γ radiation level within 50 km of the nuclear power base remains unchanged. The emission of gaseous effluent from the operation of the nuclear power plant does not have a cumulative impact on the radiation level of surrounding environment.

Radioactivity levels in foods during 2013 to 2020 around Hongyanhe Nuclear Power Plant and study on internal doses to the public / 中华放射医学与防护杂志

Objective:To evaluate the impacts of radioactivity in foods since begining of the operation of the Hongyanhe Nuclear Power Plant (HNPP).Methods:The levels of radioactivity in foods collected within 30 km of HNPP from 2013 to 2020 were analyzed by comparison of the control samples and those collected before the operation. The impacts on the operation of the HNPP on foods were evaluated.Results:The man-made radionuclides such as 131I, 134Cs, 60Co, 58Co, 110Ag m were not found in food samples. The nautral radionuclides such as 238U, 226Ra, 232Th, 40K were at the normal levels, with the average levels of (0.088±0.053), (0.155±0.178), (0.314±0.388)and(81.3±18.1)Bq/kg(fresh weight)in foods, respectively. The average levels of man-made nuclide 137Cs in foods were (0.013±0.010) Bq/kg (fresh weight). There was no increase in radionuclide levels compared with the control samples and the samples before the operation. Conclusions:The impacts on foods due to the operation of HNPP was not found.

Analysis of monitored results of death cause in residents around Sanmen nuclear power plant from 2015 to 2019 / 中华放射医学与防护杂志

Objective:To investigate the data on death cause of residents around Sanmen nuclear power plant from 2015 to 2019.Methods:The data on death cause of residents in Sanmen county from 2015 to 2019 were collected, and the top 10 diseases in death causes ranking and radiation-related malignant tumors were analyzed.Results:The average mortality rate of residents in Sanmen county was 575.87 per 100 000 population from 2015 to 2019, lower than the national level and close to that in Zhejiang Province. The top 10 death causes remain unchanged, higher than 95.79% of total deaths. The mortality rate of malignant tumor increased from 159.23 per 100 000 population in 2015 to 191.51 per 100 000 population in 2019 (χ 2=15.889, P<0.05). There was no significant difference in the proportion of mortality from radiation-related tumor(leukemia and thyroid cancer) in Sanmen county in recent 5 years ( P>0.05). Conclusions:From 2015 to 2019, the death rates of residents in Sanmen county were relatively stable. The effects of the operation of the nuclear power plant on the health of the local residents need to be continuously monitored.

Establishment of zebrafish calculation model and calculation of relative dose coefficients / 中华放射医学与防护杂志

Objective:To assess impact of radiation from nuclear power on the surrounding environment, a dose assessment model was constructed and relevant dose coefficients were determined through refined animal models.Methods:Zebrafish is one of the most important aquatic model animals in the radiation hazard assessment of nuclear power liquid effluent. A geometric model of zebrafish containing internal bones and visceral organ was established for dose estimation. The internal and external dose coefficients (DC) of the zebrafish model were calculated by Monte Carlo method with seven nuclides as the source term, 3H, 40K, 58Co, 60Co, 110Ag, 134Cs, 137Cs, which are common in nuclear liquid effluents and environmental monitoring. Results:The level of nuclide gamma energy determines dose coefficients for external radiation. The dose coefficients of most nuclides in internal organs was higher than that in whole body, and the internal organ dose of 58Co was 165% higher than that in whole body. The internal radiation dose coefficients of the model established in this study was relatively high, and the internal radiation dose coefficients caused by 60Co was 2.6 times of existing ellipsoid model, which suggested that the different internal materials and the choice of different particle types would affect the energy deposition. Conclusions:Refining of model animals is important. Accurate assessment of the organs dose coefficients of model animals is helpful to assess the radiation effects on non-human species.