Key outcome summaries of the scientific programme of the IRPA15 congress.

This special issue of JRP includes a selection of research papers and review articles presented at the 15th Congress of the International Radiation Protection Association (IRPA15) as chosen by the scientific committee. All invited journal contributions are suitably expanded beyond the initial conference presentations to meet the criteria for a full journal article and include (a) presentation within a comprehensive radiological protection context and (b) additional data/interpretation. Published contributions address a wide spectrum of scientific topics and concepts to further develop the radiation protection (RP) system. They are based on scientific evidence and available experience in a wide spectrum of applications of the protection system. The IRPA is the international voice of the RP profession. It promotes excellence in RP by providing benchmarks of good practice, enhancing professional competence, and encourages the application of the highest standards of professional conduct, skills and knowledge for the benefit of individuals and society. Within the overarching theme of the conference 'Bridging RP Culture and Science-Widening Public Empathy' IRPA15 provided an invaluable opportunity to discuss and strengthen the relations between RP culture and science, and share developing scientific knowledge and related experience in RP among members of the scientific community, between representatives of key international organizations, including ICRP, IAEA, WHO, and NEA but also with the public. Some discussions focused on the rationale of available RP programmes and priorities, with an opportunity to identify and further develop key scientific issues of the current RP system as well as key processes for the interaction between members of the scientific community and society. The scientific programme of IRPA15 included eight topics and four thematic areas. The topical areas were: Underpinning Science; Dosimetry and Measurement; the System of Protection; Standards and Regulation; Practical Implementation-Medical Sector, as well as Industry and Research; Emergency Preparedness and Response; Existing Exposures and Non-ionizing Radiation. The thematic areas addressed were: Ethics; Communication and Public Understanding; RP Culture; Human Capital and Competency.

Development of operational intervention levels for events with release of radionuclides.

An essential part of a protection strategy for radiological emergencies is the development of national dose criteria and of operational intervention levels (OILs) to decide about protective measures for all ten scenarios Germany is preparing. For the process of planning and implementing such protection strategies as required by the German Radiation Protection Law the Federal Ministry BMU has commissioned the German Radiation Protection Commission (SSK) to recommend dose criteria and OILs for emergency response measures. OILs link a chosen dose criterion for a protective action with a suitable measurement of the contamination situation such as ambient dose rate (µSv h-1), contamination level on surfaces (Bq cm-2) or activity content (Bq g-1, Bq cm-3). This link should adequately model the exposure of persons during a defined exposure period (e.g. seven days, one year) caused by the measured contamination. Dose calculations to quantify OILs should apply assumptions and parameter values that are in tendency realistic and not unduly conservative. OILs have been developed for the following emergency response actions based on radiation measurements:Sheltering on the basis of dose rate (µSv h-1) and contamination level(Bq cm-2).Evacuation on the basis of dose rate (µSv h-1) and contamination level(Bq cm-2).Establishing a radiological hazard area to implement access andcontamination control on the basis of dose rate (µSv h-1) and contaminationlevel (Bq cm-2).Contamination control and possibly decontamination of persons and objects(items, goods, vehicles, etc) based on contamination level (Bq cm-2).A set of precautionary early actions: warning the population not toconsume freshly contaminated food and agricultural measures to reducefood contamination based on dose rate (µSv h-1).Application of maximum permitted levels of radioactive contamination offood and feed (Bq kg-1) according to Euratom Regulation.

Dose limits for occupational exposure to ionising radiation and genotoxic carcinogens: a German perspective.

This paper summarises the view of the German Commission on Radiological Protection ("Strahlenschutzkommission", SSK) on the rationale behind the currently valid dose limits and dose constraints for workers recommended by the International Commission on Radiological Protection (ICRP). The paper includes a discussion of the reasoning behind current dose limits followed by a discussion of the detriment used by ICRP as a measure for stochastic health effects. Studies on radiation-induced cancer are reviewed because this endpoint represents the most important contribution to detriment. Recent findings on radiation-induced circulatory disease that are currently not included in detriment calculation are also reviewed. It appeared that for detriment calculations the contribution of circulatory diseases plays only a secondary role, although the uncertainties involved in their risk estimates are considerable. These discussions are complemented by a review of the procedures currently in use in Germany, or in discussion elsewhere, to define limits for genotoxic carcinogens. To put these concepts in perspective, actual occupational radiation exposures are exemplified with data from Germany, for the year 2012, and regulations in Germany are compared to the recommendations issued by ICRP. Conclusions include, among others, considerations on radiation protection concepts currently in use and recommendations of the SSK on the limitation of annual effective dose and effective dose cumulated over a whole working life.

Radiological protection issues arising during and after the Fukushima nuclear reactor accident.

Following the Fukushima accident, the International Commission on Radiological Protection (ICRP) convened a task group to compile lessons learned from the nuclear reactor accident at the Fukushima Daiichi nuclear power plant in Japan, with respect to the ICRP system of radiological protection. In this memorandum the members of the task group express their personal views on issues arising during and after the accident, without explicit endorsement of or approval by the ICRP. While the affected people were largely protected against radiation exposure and no one incurred a lethal dose of radiation (or a dose sufficiently large to cause radiation sickness), many radiological protection questions were raised. The following issues were identified: inferring radiation risks (and the misunderstanding of nominal risk coefficients); attributing radiation effects from low dose exposures; quantifying radiation exposure; assessing the importance of internal exposures; managing emergency crises; protecting rescuers and volunteers; responding with medical aid; justifying necessary but disruptive protective actions; transiting from an emergency to an existing situation; rehabilitating evacuated areas; restricting individual doses of members of the public; caring for infants and children; categorising public exposures due to an accident; considering pregnant women and their foetuses and embryos; monitoring public protection; dealing with 'contamination' of territories, rubble and residues and consumer products; recognising the importance of psychological consequences; and fostering the sharing of information. Relevant ICRP Recommendations were scrutinised, lessons were collected and suggestions were compiled. It was concluded that the radiological protection community has an ethical duty to learn from the lessons of Fukushima and resolve any identified challenges. Before another large accident occurs, it should be ensured that inter alia: radiation risk coefficients of potential health effects are properly interpreted; the limitations of epidemiological studies for attributing radiation effects following low exposures are understood; any confusion on protection quantities and units is resolved; the potential hazard from the intake of radionuclides into the body is elucidated; rescuers and volunteers are protected with an ad hoc system; clear recommendations on crisis management and medical care and on recovery and rehabilitation are available; recommendations on public protection levels (including infant, children and pregnant women and their expected offspring) and associated issues are consistent and understandable; updated recommendations on public monitoring policy are available; acceptable (or tolerable) 'contamination' levels are clearly stated and defined; strategies for mitigating the serious psychological consequences arising from radiological accidents are sought; and, last but not least, failures in fostering information sharing on radiological protection policy after an accident need to be addressed with recommendations to minimise such lapses in communication.

State of the art in research into the risk of low dose radiation exposure--findings of the fourth MELODI workshop.

The fourth workshop of the Multidisciplinary European Low Dose Initiative (MELODI) was organised by STUK-Radiation and Nuclear Safety Authority of Finland. It took place from 12 to 14 September 2012 in Helsinki, Finland. The meeting was attended by 179 scientists and professionals engaged in radiation research and radiation protection. We summarise the major scientific findings of the workshop and the recommendations for updating the MELODI Strategic Research Agenda and Road Map for future low dose research activities.

Preparing a scientific report to the general assembly on 'exposures due to the nuclear accident following the Great East-Japan earthquake and tsunami'.

At its 58th session in May 2011, the United Nations Committee on the Effects of Atomic Radiation (UNSCEAR) decided to carry out, once sufficient information was available, a full assessment of the levels of exposure and radiation risks attributable to the Fukushima accident. It envisages a preliminary document for consideration at its 59th session in May of 2012 and a more complete report for the 60th session of the Committee in 2013. This paper summarises the aims and objectives of the project, the scope, the working arrangements as well as the relation of the work to other activities.

The European strategy on low dose risk research and the role of radiation quality according to the recommendations of the "ad hoc" High Level and Expert Group (HLEG).

Health effects of exposures at low doses and/or low dose rates are recognized as requiring intensive research activity to answer several questions. To address these issues at a strategic level in Europe, with the perspective of integrating national and EC efforts (in particular those within the Euratom research programmes), a "European High Level and Expert Group (HLEG) on low dose risk research" was formed and carried out its work during 2008. The Group produced a report published by the European Commission in 2009 and available on the website http://www.hleg.de . The more important research issues identified by the HLEG were as follows: (a) the shape of dose-response for cancer; (b) the tissue sensitivities for cancer induction; (c) the individual variability in cancer risk; (d) the effects of radiation quality (type); (e) the risks from internal radiation exposure; and (f) the risks of, and dose response relationships for, non-cancer diseases. In this paper, the radiation quality issues are especially considered, since they are closely linked to health problems and related radioprotection in space and in emerging radiotherapeutic techniques (i.e., hadrontherapy). The peculiar features of low-fluence, high-LET radiation exposures can question in particular the validity of the radiation-weighting factor (w ( R )) approach. Specific strategies are therefore needed to assess such risks. A multi-scale/systems biology approach, based on mechanistic studies coordinated with molecular-epidemiological studies, is considered essential to elucidate differences and similarities between specific effects of low- and high-LET radiation.

Noninvasive detection of lung cancer by analysis of exhaled breath.

BACKGROUND: Lung cancer is one of the leading causes of death in Europe and the western world. At present, diagnosis of lung cancer very often happens late in the course of the disease since inexpensive, non-invasive and sufficiently sensitive and specific screening methods are not available. Even though the CT diagnostic methods are good, it must be assured that "screening benefit outweighs risk, across all individuals screened, not only those with lung cancer". An early non-invasive diagnosis of lung cancer would improve prognosis and enlarge treatment options. Analysis of exhaled breath would be an ideal diagnostic method, since it is non-invasive and totally painless. METHODS: Exhaled breath and inhaled room air samples were analyzed using proton transfer reaction mass spectrometry (PTR-MS) and solid phase microextraction with subsequent gas chromatography mass spectrometry (SPME-GCMS). For the PTR-MS measurements, 220 lung cancer patients and 441 healthy volunteers were recruited. For the GCMS measurements, we collected samples from 65 lung cancer patients and 31 healthy volunteers. Lung cancer patients were in different disease stages and under treatment with different regimes. Mixed expiratory and indoor air samples were collected in Tedlar bags, and either analyzed directly by PTR-MS or transferred to glass vials and analyzed by gas chromatography mass spectrometry (GCMS). Only those measurements of compounds were considered, which showed at least a 15% higher concentration in exhaled breath than in indoor air. Compounds related to smoking behavior such as acetonitrile and benzene were not used to differentiate between lung cancer patients and healthy volunteers. RESULTS: Isoprene, acetone and methanol are compounds appearing in everybody's exhaled breath. These three main compounds of exhaled breath show slightly lower concentrations in lung cancer patients as compared to healthy volunteers (p < 0.01 for isoprene and acetone, p = 0.011 for methanol; PTR-MS measurements). A comparison of the GCMS-results of 65 lung cancer patients with those of 31 healthy volunteers revealed differences in concentration for more than 50 compounds. Sensitivity for detection of lung cancer patients based on presence of (one of) 4 different compounds not arising in exhaled breath of healthy volunteers was 52% with a specificity of 100%. Using 15 (or 21) different compounds for distinction, sensitivity was 71% (80%) with a specificity of 100%. Potential marker compounds are alcohols, aldehydes, ketones and hydrocarbons. CONCLUSION: GCMS-SPME is a relatively insensitive method. Hence compounds not appearing in exhaled breath of healthy volunteers may be below the limit of detection (LOD). PTR-MS, on the other hand, does not need preconcentration and gives much more reliable quantitative results then GCMS-SPME. The shortcoming of PTR-MS is that it cannot identify compounds with certainty. Hence SPME-GCMS and PTR-MS complement each other, each method having its particular advantages and disadvantages. Exhaled breath analysis is promising to become a future non-invasive lung cancer screening method. In order to proceed towards this goal, precise identification of compounds observed in exhaled breath of lung cancer patients is necessary. Comparison with compounds released from lung cancer cell cultures, and additional information on exhaled breath composition in other cancer forms will be important.

CHERNOBYL THYROID CANCER: 30 YEARS OF FOLLOW-UP OVERVIEW.

A substantial increase of the thyroid cancer incidence has been observed after the Chernobyl accident in the whole of Belarus and Ukraine, and the four most affected oblasts of the Russian Federation among those exposed as children or adolescents. The dominant risk factor was the thyroid exposure by 131I resulting from the ingestion of milk. A minimum latency period for the identification of the thyroid cancer incidence of 4-5 years has been observed. The cancer incidence among males who were 10 years old at the time of the accident was more than a factor of 4 lower than among females. The incidence data in this age group registered during the period 1991-2015 continuously increased with time to approach a number of 20.000 thyroid cancer cases at the end of this period. From a scientific point of view there is an obligation to pursue programs for long-term medical follow up of the most affected populations. The lessons learned during the past 30 years should be used to improve the standards and criteria for emergency preparedness and response.

Thyroid artery erosion by esophageal cancer: management with interventional radiology.

Management of upper gastrointestinal bleeding because of erosion of vessels by esophageal cancer may be challenging. We present herein the angiographic images of a 49-year-old patient who was admitted with massive bleeding from a tumor-eroded inferior thyroid artery. Attempts to control the bleeding by means of flexible endoscopy and insertion of a Sengstaken-Blakemore tube had failed. The diagnosis was impressively demonstrated by multislice computed tomography with intravenous contrast in the arterial phase and multiplanar reconstructions (computed tomography angiography) and by digital subtraction angiography. The bleeding was successfully treated with superselective catheterization and coiling of the eroded vessel.

Transcutaneous oximetry compared to ankle-brachial-index measurement in the evaluation of percutaneous transluminal angioplasty.

OBJECTIVE: To investigate transcutaneous oximetry as parameter of the microcirculation is correlated to ankle-brachial-index as parameter of the macrocirculation after peripheral angioplasty procedures. DESIGN: Prospective study. MATERIALS AND METHODS: 60 patients suffering from intermittent claudication were scheduled for angioplasty treatment. 45 patients were considered as eligible for angioplasty after angiographic evaluation, 15 patients underwent angiography only. Transcutaneous oximetry measurements were performed before the procedure, at the end of intervention, 24h as well as 2 and 4 weeks after percutaneous transluminal angioplasty. Ankle-brachial-indices were obtained before intervention, 24h as well as 2 and 4 weeks later. RESULTS: Ankle-brachial-indices increased significantly at 24h after angioplasty in patients being treated with angioplasty. Transcutaneous oximetry values dropped significantly at the end of the procedure and returned close to the baseline levels at 2 and 4 weeks after angioplasty. Ankle-brachial-indices and transcutaneous oximetry were positively correlated before (r=0.3833, p=0.009) as well as 4 weeks after angioplasty (r=0.4596, p=0.001). Immediately after radiological interventions, ankle-brachial-indices and transcutaneous oximetry are not positively correlated. In patients undergoing angiography only, transcutaneous oximetry levels drop significantly immediately after angiography and remain at decreased levels even at 4 weeks after intervention. CONCLUSION: Transcutaneous oximetry as parameter of the microcirculation is positively correlated with ankle-brachial-index as parameter of the macrocirculation before and at 4 weeks after angioplasty. Intraarterial angiography leads to a sudden decrease in skin microcirculation without affecting macrocirculation. As indicated by a lack of recovery in transcutaneous oximetry levels after 4 weeks, angiography alone results in a prolonged impaired microcirculation which may reflect endothelial dysfunction caused by contrast material. The recovery of transcutaneous oximetry levels following angioplasty is counterbalanced by the adverse effects of the contrast material. Ankle-brachial-indices remains the most favourable parameter in evaluating the success of angioplasty procedures while transcutaneous oximetry serves as an indirect method in assessing endothelial dysfunction caused by contrast material.

Diguanosine pentaphosphate: an endogenous activator of Rho-kinase possibly involved in blood pressure regulation.

OBJECTIVE: Rho-kinase activity is increased in cardiovascular disease and in the pathophysiology of hypertension. Few endogenous factors are known that activate the Rho-kinase pathway. Stimulation of P2Y receptors activates the Rho-kinase pathway. Recently identified diguanosine pentaphosphate (Gp5G) possibly activates P2Y receptors. In this study, Gp5G was identified and quantified in human plasma. The influence of Gp5G on vascular tone was studied. METHODS: Gp5G in human plasma was purified to homogeneity by several steps. Gp5G was quantified and identified by matrix-assisted laser desorption/ionization mass spectrometry and enzymatic analysis. The vasoactive effects of Gp5G were studied in the isolated perfused rat kidney and after intra-aortic application. Activation of Rho-kinase was measured using western blot analysis. RESULTS: The plasma level of Gp5G in healthy donors is 9.47 +/- 4.97 nmol/l. Gp5G increases contractile responses induced by angiotensin II in a dose-dependent way [ED50 (-log mol) angiotensin II: 10.9 +/- 0.1; angiotensin II plus Gp5G (100 nmol/l): 11.5 +/- 0.1]. P2 receptor antagonists inhibited the Gp5G-induced increase in angiotensin II vasoconstriction. MRS2179, a selective P2Y1 receptor antagonist, had no effect on Gp5G-mediated angiotensin II potentiation. Rho-kinase inhibition by Y27632 abolished the Gp5G-induced increase of contractile responses to angiotensin II. Concentrations of 10 nmol/l Gp5G activated the translocation of RhoA from the cytosolic to the membranous fraction indicating the activation of Rho-kinase. The intra-aortic application of 100 pmol Gp5G significantly increased mean arterial blood pressure by 13.5 +/- 4.2 mmHg. CONCLUSION: Gp5G is an endogenous activator of Rho-kinase, which might affect vascular tone control by Rho-kinase at physiological levels. Gp5G activates P2Y4&6 receptors, and might play a role in physiological and pathophysiological vascular tone control.

Radiological Protection Issues Arising During and After the Fukushima Nuclear Reactor Accident-Memorandum of TG 84 of ICRP.

Observations and lessons identified after the Fukushima accident have been collected and assessed by ICRP Task Group 84. Together with the observations of other expert organizations, they are being used to further develop the current system of protection. While many of the established protection criteria remain valid, improvements are needed in three areas. Key issues related to the need of planning for long-term protective actions (criteria for returning home, dealing with waste) have to be implemented as important elements of the national protection strategies during the preparedness stage. The justification of disruptive protective actions and the protection of vulnerably groups of the population need to be reconsidered to avoid unpleasant imbalances and outcomes. The coexistence of radiation-induced health effects and health effects with social determinants requires consideration of both aspects in decision-making and response.

Transgenic overexpression of the sarcoplasmic reticulum Ca2+ATPase improves reticular Ca2+ handling in normal and diabetic rat hearts.

Slowed relaxation in diabetic cardiomyopathy (CM) is partially related to diminished expression of the sarcoplasmic reticulum (SR) Ca2+-ATPase SERCA2a. To evaluate the impact of SERCA2a overexpression on SR Ca2+ handling in diabetic CM, we 1) generated transgenic rats harboring a human cytomegalovirus enhancer/chicken beta-actin promotor-controlled rat SERCA2 transgene (SERCA2-TGR), 2) characterized their SR phenotype, and 3) examined whether transgene expression may rescue SR Ca2+ transport in streptozotocin-induced diabetes. The transgene was expressed in all heart chambers. Compared to wild-type (WT) rats, a heterozygous line exhibited increased SERCA2 mRNA (1.5-fold), SERCA2 protein (+26%) and SR Ca2+ uptake (+37%). Phospholamban expression was not altered. In SERCA2-TGR, contraction amplitude (+48%) and rates of contraction (+34%) and relaxation (+35%) of isolated papillary muscles (PM) were increased (P2+ uptake and SERCA2 protein of SERCA2-TGR were 1.3-fold higher (P2+ uptake, accelerates relaxation and compensates, in part, for depressed Ca2+ uptake in diabetic CM. Therefore, SERCA2 expression might constitute an important therapeutic target to rescue cardiac SR Ca2+ handling in diabetes.

Current concepts of percutaneous abscess drainage in postoperative retention.

In recent years, percutaneous abscess drainage (PAD) of intraabdominal abscesses has become an important tool with regard to the treatment of intraabdominal sepsis. The aim of this study is to assess the value of PAD in the treatment of postoperative retentions. Between 1995 and 1999, the postoperative course of 3346 patients undergoing major abdominal surgery was analyzed. Mortality, morbidity, and comparison of different locations of intraabdominal abscesses were assessed. PAD was considered successful when the patient improved clinically within 24 hours, a decrease in the size of the abscess formation was noted, and complete recovery without further surgical intervention occurred. Out of 3346 operated patients, 174 (5.2%) were diagnosed as having an intraabdominal abscess formation and were treated by PAD. In 63 patients the abscess developed within the upper quadrants, in 66 patients the abscess developed within the lower quadrants, and in the remaining 45 patients the abscess developed within the retroperitoneal cavity or pelvis. The success rate of PAD was 85.6% with a morbidity rate of 4.6%. The least successful location for PAD was the left upper quadrant. Patients with abscess drainage in the right upper and lower quadrant experienced a high success rate. One patient died due to the PAD procedure. Unsuccessful PAD was closely related to an increase in mortality. In the case of intraabdominal abscess formation after visceral surgery, PAD should be the primary procedure. Attention should be paid to abscess formations in the left upper quadrant because there is an increased likelihood of complications caused by PAD.

Microembolic signals detected by transcranial Doppler sonography during carotid endarterectomy and correlation with serial diffusion-weighted imaging.

BACKGROUND AND PURPOSE: Embolic events are a major cause for procedure-related strokes after carotid endarterectomy (CEA). Transcranial Doppler sonography can reveal embolic events as microembolic signals (MES) during CEA. MES during declamping and shunting are frequently detected. MES during shunting are rare and known to be correlated with the neurological outcome of the patient. In the present study, we analyzed the occurrence of MES within different stages of CEA and whether MES within those stages were correlated with cerebral ischemia, as detected by diffusion-weighted imaging (DWI), and brain infarction, as detected by contrast-enhanced MRI. METHODS: Thirty-three patients were monitored intraoperatively for MES using transcranial Doppler sonography. DWI was performed within 24 hours before and after surgery. Positive postoperative DWI led to reexamination with contrast-enhanced T1-MRI 7 to 10 days after CEA for detection of cerebral infarction. RESULTS: MES were detected in 32 of 33 patients. The highest number of MES was found during shunting and declamping. A significant correlation was found between MES and DWI-lesions during dissection. A significant correlation was found between MES during dissection and shunting, and nonsignificant correlation was found between MES and the occurrence of cerebral infarction. CONCLUSIONS: MES could be regularly detected during CEA. Dissection and shunting seem to be the most vulnerable stages of the procedure.

Superior mesenteric artery syndrome: diagnosis and treatment from the gastroenterologist's view.

BACKGROUND: Superior mesenteric artery syndrome (SMAS) is caused by compression of the third part of the duodenum between the superior mesenteric artery and the aorta. It occurs most frequently in patients with rapid weight loss. METHODS: We report two young patients, who each presented with a longstanding history of postprandial abdominal pain, nausea, and voluminous vomiting. The diagnosis of SMAS was established by digital fluoroscopy and contrast-enhanced spiral computed tomography (CT) scan. The findings obtained by endoscopic ultrasound (EUS) at the site of duodenal compression, using a miniprobe, were of substantial diagnostic value and in good agreement with the radiological observations. RESULTS: Both patients, once diagnosed, were treated conservatively by providing enteral or parenteral high caloric nutrition. Weight gain was accompanied by the complete relief of symptoms. CONCLUSIONS: Pathogenesis, diagnostic procedures, and therapy are reviewed in order to draw attention to this rare entity.

Spatial and temporal variations of atmospheric 85Kr observed during 1995-2001 in Japan: estimation of atmospheric 85Kr inventory in the Northern Hemisphere.

Atmospheric 85Kr concentrations have been continuously monitored since 1995 at the Meteorological Research Institute (MRI) in Tsukuba, Japan. They have also been observed once a year at several stations over the Japanese islands since 1995. The annual growth rate of the background atmospheric 85Kr concentrations in Tsukuba was 0.03 Bq x m(-3) x yr(-1) during 1996-2001. The atmospheric 85Kr concentrations at several stations over Japan were within the range of the annual variations in Tsukuba. However, higher and lower 85Kr concentrations in early winter, compared with those in Tsukuba (36.1 degrees N, 140.1 degrees E), occurred in Sapporo (43.1 degrees N, 141.3 degrees E) and Ishigaki (24.3 degrees N, 124.2 degrees E), respectively. The reason for this is that Sapporo is covered by a continental air mass, some from European sources, whereas Ishigaki is still covered by a subtropical air mass. The Northern Hemispheric background 85Kr concentrations from 1994 to 2001 was calculated from the 85Kr inventory and the release rate of 85Kr from the nuclear fuel reprocessing plants in Europe. Calculated 85Kr concentrations in surface air were in good agreement with annual average observed values at the MRI, Tsukuba. The global atmospheric inventory of 85Kr in December 2001 was also estimated to be approximately 5 EBq by using observed data in Tsukuba.

Conclusions on plutonium separation from atmospheric krypton-85 measured at various distances from the Karlsruhe reprocessing plant.

For wide-area atmospheric monitoring, krypton-85 is the best indicator for clandestine plutonium separations. The detection and false alarm rates were determined from weekly samples at five different distances from the Karlsruhe reprocessing plant between 1985 and 1988. The detection rate for the separation of 4 kg of plutonium per week was found to be as high as 80-90% at a distance of less than 1 km, 70% at 5 km, 40% at 39 km, and 15% at 130 km. At distances up to 40 km, the false alarm rate is less than 3.5%. On average, the fuel released 28 TBq krypton-85 per kg plutonium. For weapons-grade plutonium, the krypton signal would be lower by a factor of 2. Hence, the given percentages correspond to the detection probabilities for the separation of a significant quantity (8 kg) of plutonium per weekly sample under the specific meteorological conditions of the WAK. The minimum separation rates that could have been detected are 2 gram of weapons-grade plutonium per week at a distance of less than 1 km, 40 g/week at 5 km, 200 g/week at 39 km, and 1000 g/week at 130 km.