[en] he activity-concentrations of several long-lived gamma-emitting radionuclides present in technetium generators and in eluates from these generators have been determined by means of Ge(Li) gamma-spectrometry. The principal contaminants of the eluates were: ¹⁹²Ir(T sub (1/2) = 74.3 d), ¹³⁴Cs (2.05 a), ¹³¹I (8.05 d), ¹¹⁰Ag sup (m) (255 d), ¹⁰³Ru (39.5 d), ⁹⁹Mo (66.7 h) and ⁶⁰Co (5.26 a). Thhe impurity-concentrations were found to vary considerably from generator to generator. Changes in the impurity-concentrations in eluates from the same generator have also been recorded during an elution-period of one week. In accord with their ability to be eluted from the generators, the long-lived radionuclide-impurities may be arranged in the following sequence ¹³⁴Cs > ¹⁰³Ru greater than or equal to ¹¹⁰Ag sup (m) > ¹⁹²Ir > ⁶⁰Co. (author)

[en] The accumulation, retention and internal cycling of the fallout radionuclide ¹³⁷Cs (physical half-life = 30.2 a) has been studied in forest moss (Pleurozium schreberi) collected in southern Sweden (56.4 deg N, 14.3 deg E) during the period 1961-1973. The highest ¹³⁷Cs-concentrations have been found in the green top parts of the living plants. The study shows that a dominating part of the deposited ¹³⁷Cs is available for transport from dying to growing parts of the plants. The elimination of ¹³⁷Cs from living moss-plants as well as from dead modd during the period 1968-1973 can be characterized by the same mean residence time, (4 +- 1)a. The radionuclide ¹³⁷Cs and the naturally occurring stable element potassium show different behaviour in the moss vegetation, so that the ¹³⁷Cs/K-ratio is higher by a factor of approximately 2 in the dead parts of the moss than in the living parts. The vertical distribution of ¹³⁷Cs in the moss-covered ground has been studied down to a dry-mass depth of about 100 kg m^-2 and can theoretically be described by a model which was earlier empirically deduced for lichen-covered ground (Mattsson, 1972). The relative penetration of ¹³⁷Cs is around five times higher in the ground covered by moss-carpets than in the ground covered by lichen-carpets. During the period 1969-1973, the total amount of ¹³⁷Cs retained in the moss-carpet was found to be 64.2 +- 2.2 nCi m^-2. (author)

[en] The activity concentration of ¹³⁷Cs, ¹³¹I, ⁶⁵Zn, ⁶⁰Co, ⁵⁸Co, ⁵⁴Mn, and ⁴⁰K were determined in samples of brown seaweed (Fucus) and some other marine plants using low background high-resolution gamma-spectrometry. The algae were mainly sampled in the bay just north of the Barsebaeck NPP (55.4 N, 12.6 E) in the south of Sweden to study the contamination levels in the nearest shallow waters. One aim of the study was to investigate whether the levels were high enough to expect environmental effects. Some samples were also taken at longer distances up to 130 km from the Barsebaeck NPP. Measurable levels of the neutron activation products ⁶⁵Zn (up to 17 Bq/kg dw), ⁶⁰Co (100-600 Bq/kg dw), ⁵⁸Co (1-160 Bq/kg dw) and ⁵⁴Mn (12-90 Bq/kg dw) were found in the algae samples within a distance of 5 km from the plant. The decrease in activity concentration with distance from the plant could be described by a power function with an exponent ranging from 1.4 to 2.4. This was in fair agreement with the value for a true two-dimensional dispersion model. The present-day concentrations were found to be considerably lower than in earlier studies made in the late 1970s, especially for ⁶⁵Zn and ⁵⁸Co. The activity concentration of gamma emitting radio-nuclides in Fucus vesiculosus from the bay just north of Barsebaeck is today dominated by (in order of decreasing concentration): natural ⁴⁰K, ⁶⁰Co from the plant, ¹³⁷Cs mainly from the Chernobyl debris, ⁵⁴Mn and ⁵⁸Co from the plant. It is not likely that any effects from the very marginal absorbed dose contribution from the Barsebaeck NPP releases can be found even in the nearest environment. The study has also shown that the eelgrass Zostera marina may be a bioindicator to use in further studies of the radiation environment in shallow water, especially for ⁶⁰Co and ⁵⁴Mn. (author)(tk)

[en] The work is aimed at studying the possibility of direct radionuclide concentration measurements in gaseous reactor release with a semiconducting detector (SCD) on the basis of high-frequency high-resolution germanium, as well as at applying the results of such measurements to estimate parameters of the model used and to calculate maximum permissible release. The method of identification and determination of the power of radioactive noble gas release is described. The results of calculations are compared with the experimental data. The minimum detected release power is estimated.The conclusion is made that the above detectors are applicable to measure radioactive releases both in the case of normal reactor operation and in emergencies as they can be used to estimate concentration of separate radionuclides. The application of germanium SCD enables one to obtain information on the time of release transfer in data on such short-lived daughter radionuclides as ⁸⁸Rb

[en] The paper deals with the use of conventional liquid scintillators for the detection of the ¹⁴C level in the environment of the Swedish Ringhals nuclear power plant. As ¹⁴C is discharged through the ventilation, mainly in the form of CO₂, tree's growth rings (annual rings) have been utilized as bioindicators for ¹⁴C discharge. The results precented demonstrate that it is feasible to measure an increase of some 10 per cent beyond the natural occuring ¹⁴C level in vegetation material. Any measurable increase in the ¹⁴C level in the environment of the Ringhals plant has not been demonstrated

[en] The possible ways to optimise the relation between diagnostic information and patient absorbed dose differ between nuclear medicine and X ray imaging. In nuclear medicine, very little has been done to find an optimal dosage of radiopharmaceuticals. Current nuclear medicine methods are discussed in the light of the recent ICRP Publications and the new EU Patient Directive. The paper also discusses how reference levels for administered activity may be derived from patient studies. In order to eliminate the most inappropriate choices (too low or too high activities), knowledge of the current statistical distribution of administered activities may be helpful. Different methods to estimate the amount of activity that should be administered to children of various body sizes to guarantee the same image quality as for adults are also discussed. Examples of current activity levels for common nuclear medicine procedures, indicating the state of the practice, are given. (author)

No abstract available

[en] The absorbed whole-body dose to the personnel working full time with nuclear medicine investigations in vivo is found to be 1-4 m Gy/a, as measured on the film badge and corresponding to a dose equivalent of 0.7 to 2.8 m Sv. The patient is contributing 1 to 2 m Gy. The absorbed dose to the fingers of the personnel easily exceeds 500 m Sv/a emanating from the syringes and bottles. The injection of patients renders the highest exposures. If rubber gloves were not used the contamination from 1 kBq ⁹⁹Tc(sub)m will be 0.5 Gy/h^-1 to the skin. Latex rubber gloves will provide sufficient protection when used less than for 30 minutes. (G.B.)

[en] The macroalgae Fucus vesiculosus has been used as a bioindicator for mapping the release of radionuclides from a nuclear power station into the marine environment. Both the time variation of radionuclide concentration in Fucus and its variation by distance from the power plant have been studied. The uptake and retention of different activation products in Fucus are compared. The concentration of ⁶⁰Co in Idothea viridis, Idothea baltica and Gammarus oceanicus living in the Fucus plants is also given

[en] Samples of sewage sludge, lichen (Cladonia alpestris), soil and ground level air have been analysed for activation products released to the atmosphere from the three Swedish nuclear power stations at Simpevarp near Oskarshamn, Ringhals and Barsebaeck. The activity concentration of the activation products in the sludge can be arranged in the following sequence: ⁶⁰Co > ⁶⁵Zn > ⁵⁸Co ⁵⁴Mn. There is agreement between the time variation of the activity concentration in the sludge and the reported releases to the air from the power stations. The measured activity ratio ⁵⁸Co/⁶⁰Co in sludge does not significantly differ from that reported in the releases to the air. The activity concentration in sludge sedimented from incoming waste water has been used to get better time resolution than using only digested sludge from the final step of the plant. These studies have shown that the activity concentration of ⁶⁰Co increases substantially with the first rain run-off that reaches the sewage plant and then falls off rapidly. Measurements on samples of lichen and underlying soil show that the radioactive cobalt isotopes (⁵⁸Co and ⁶⁰Co) have a short mean residence time in the lichen carpet compared to most fission products present in global fall-out. (author)