239Pu Activity Research Articles

Radioactive Fission Waste of The Conversion of High-Enriched Uranium to Low-Enriched Uranium Target on 99Mo Production

In the past, 99mTc produced by PT. Industri Nuklir Indonesia (PT. INUKI) was carried out through the processing of a 99Mo parent radioisotope that was produced using high enriched uranium target. Due to restrictions on the use of high-enriched uranium (HEU) by the International Atomic Energy Agency, PT. INUKI has converted the process using a low enriched uranium (LEU) target. This study aims to determine the change of radioactive fission waste characteristics in 99Mo production due to the conversion process. The characteristics of radioactive fission waste generated from low-enriched uranium targets were calculated using ORIGEN 2.1 program. The results show that the radioactive fission waste contains radionuclides of activation products, actinides, and fission products. The conversion produced smaller activity of 99Mo compared to that of using the HEU target, which was 397 compared to 1010 Ci. The conversion generated radioactive fission waste with a smaller content of remaining 235U but greater content of actinides, particularly 239Pu. The activity of 239Pu in the radioactive fission waste from LEU was 29.1 μCi, approximately 19 times higher compared to that of using HEU, which was 1.52 μCi. After 50 years of decay, this radioactive fission waste was calculated to have a specific activity of 6.54x108 Bq/g, lower than that of the highly enriched uranium target, which was 3.01x109 Bq/g. This radioactive fission waste requires management with a high safety level.

Effects of %FIMA on Storage-Safety Parameters of Spent Fuel from Experimental Pebble-Bed Reactor

The back end of the utilization of nuclear technology is safety and management of spent fuel, which is a key element contributing to the success of the nuclear power plant program. Indonesia’s National Nuclear Energy Agency resolved to establish an experimental power reactor, called RDE, as a nuclear power plant demo. The fuel of this reactor is similar to that of German’s experimental pebble-bed reactor (PBR), Arbeitsgemeinschaft Versuchsreaktor(AVR). In this study, the spent fuel of AVR was studied to obtain the safety parameter data for storage of RDE spent fuel by varying the fission in the initial metallic atoms (%FIMA). These parameters that must be studied include the radioactivity, decay heat, proliferation threats of both 239Pu and 235U, and the presence of 137Cs, a dangerous fission product that can escape from damaged spent fuels. The calculation was conducted by ORIGEN 2.1. The result of the study demonstrates a higher %FIMA indicates a higher safety level that is required since the activity and decay heat of the spent fuel will increase and, as will be the total amounts of 239Pu and 137Cs. However, the 235U amount will decrease. For a 100 years storage of spent fuel, the optimum %FIMA is 8.2 with a canister capacity of 1,900 pebbles. Further, the activity and decay heat of the spent nuclear fuel are 2.013 × 1013 Bq and 6.065 W, respectively. The activities of 239Pu, 137Cs, and 235U are 5.187 ×1011, 7.100 × 1012, and 7.339 × 107 Bq, respectively.

Mapping the age of ice of Gauligletscher combining surface radionuclide contamination and ice flow modeling

Abstract. In the 1950s and 1960s, specific radionuclides were released into the atmosphere as a result of nuclear weapons testing. This radioactive fallout left its signature on the accumulated layers of glaciers worldwide, thus providing a tracer for ice particles traveling within the gravitational ice flow and being released into the ablation zone. For surface ice dating purposes, we analyze here the activity of 239Pu, 240Pu and 236U radionuclides derived from more than 200 ice samples collected along five flowlines at the surface of Gauligletscher, Switzerland. It was found that contaminations appear band-wise along most of the sampled lines, revealing a V-shaped profile consistent with the ice flow field already observed. Similarities to activities found in ice cores permit the isochronal lines at the glacier from 1960 and 1963 to be identified. Hence this information is used to fine-tune an ice flow/mass balance model, and to accurately map the age of the entire glacier ice. Our results indicate the strong potential for combining radionuclide contamination and ice flow modeling in two different ways. First, such tracers provide unique information on the long-term ice motion of the entire glacier (and not only at its surface), and on the long-term mass balance, and therefore offer an extremely valuable data tool for calibrating ice flows within a model. Second, the dating of surface ice is highly relevant when conducting “horizontal ice core sampling”, i.e., when taking chronological samples of surface ice from the distant past, without having to perform expensive and logistically complex deep ice-core drilling. In conclusion, our results show that an airplane which crash-landed on the Gauligletscher in 1946 will likely soon be released from the ice close to the place where pieces have emerged in recent years, thus permitting the prognosis given in an earlier model to be revised considerably.

Determination of 239,240Pu, 238Pu isotopes in soil samples using molecular recognition technology product AnaLig®Pu-02 gel

Procedure for analysis of plutonium isotopes in soil samples was developed using a new molecular recognition technology product AnaLig®Pu-02 gel. Extraction chromatography TEVA® Resin was used for purification of plutonium phase to remove thorium impurities which interfere in Pu determination by alpha spectrometry. The performance of the method was successfully tested by analysis of a sand stimulant sample and a soil sample spiked with known activity of 239Pu. The results obtained for procedures were compared in terms of activities and recoveries.

Determination of plutonium isotopes in seawater reference materials using isotope-dilution ICP-MS

We analyzed the activities of 239Pu, 240Pu, 239+240Pu, 241Pu, the ratio of number of atoms (atom ratio) for 240Pu/239Pu, and the activity ratio of 241Pu/239+240Pu in seawater reference materials, IAEA-443 and IAEA-381, using a highly sensitive isotope dilution sector field inductively coupled plasma mass spectrometry method. With a mean chemical yield of 65% determined with 242Pu as a tracer, we found that the experimentally established values in IAEA-443 for 239Pu, 240Pu, 241Pu and 239+240Pu activities are almost the same as those in IAEA-381. Regarding the 239+240Pu activity, we provided the most precise and accurate result among the twelve laboratories, which participated in the interlaboratory comparison. In addition, for the 240Pu/239Pu atom ratio, our results for IAEA-381 (0.2315±0.0008) and IAEA-443 (0.2325±0.0008) are in good agreement with the IAEA information value (0.229±0.006), but have much smaller uncertainty. Since the new seawater reference material, IAEA-443, is commercially available, it can be used not only for method validation for seawater plutonium isotope ratio and activity analysis, but also for more general use as a plutonium isotope standard for mass discrimination correction for other environmental samples.

Precise Determination of Pu Isotopes in a Seawater Reference Material Using ID-SF-ICP-MS Combined with Two-stage Anion-Exchange Chromatography

In order to obtain the precise Pu isotope composition of Irish Sea water reference material issued by the International Atomic Energy Agency (IAEA-381), we analyzed the activities of (239)Pu, (240)Pu and the atom ratio of (240)Pu/(239)Pu by a highly sensitive isotope dilution SF-ICP-MS method combined with two-stage chromatographic separation and purification. With a mean chemical yield of 65% for (242)Pu tracer, the experimentally established values for (239)Pu, (240)Pu and (239+240)Pu activities are in good agreement with the certified ones. For the (240)Pu/(239)Pu atom ratio, we obtain a value of 0.2315 +/- 0.0008 with a high precision (RSD, 0.35%), which is much more precise than the information value of 0.22 +/- 0.03 (RSD, 13.6%) provided by the IAEA certification report. The precise determination of Pu isotopes in this seawater reference material will be useful for the validation of analytical methods for the study of radionuclides in the marine environment.

Developing instruments for measurement of plutonium activity in the environmental samples in the case of radiation accident

According to the Russian norms, the permissible specific activity of 239Pu in the air and water are the lowest. Still the problem of low (compared to permissible) Pu activity measurement for environmental samples arises, for instance, in the case of radiation accident during transportation or storage of excess weapons-grade plutonium transferred to the civil sphere of utilisation. The base method of Pu activity measurement is alpha spectrometry by using silicon detector. A new model of alpha spectrometer, based on silicon surface-barrier detector with background level less than 1-3 pulses per day has been developed. A simple unfolding method for the determination of Pu activity of samples with various thickness based on alpha spectrum measurement has been also developed. L-X photon detection is also used for reducing the measurement threshold of Pu activity determination. A method based on detecting L-X photons of Pu, excited by X rays and beta particles, is applied for further reducing the threshold.

Rapid dating of recent aquatic sediments using Pu activities and 240Pu/239Pu as determined by quadrupole inductively coupled plasma mass spectrometry.

Quadrupole inductively coupled plasma mass spectrometry has been used to rapidly establish the chronology of recent aquatic sediments via measurements of the activities of 239Pu, 240Pu, and the atom ratio 240Pu/239Pu. Following addition of 0.007 Bq of a 242Pu spike isotope, Pu is leached from 3-20 g aliquots of dry-ashed sediments with HNO3. A selective anion exchanger is used to preconcentrate Pu into approximately 2 mL aliquots, which are directly analyzed using a pneumatic nebulizer and double-pass spraychamber operating at 60 microL/min solution uptake rate. The ICPMS data collection is performed for 10 min per sample. The U concentrations were 0.01-0.05 microg/L in the analyzed solutions, and the interference of 238U1H+ upon 239Pu+ was negligible. The method has been applied to determining Pu activities, inventory, and 240Pu/239Pu in a complete sediment core from Old Woman Creek (Huron, OH). The Pu activity profiles, obtained in approximately 6 h of instrumental measurement time, are in agreement with a y spectrometric 137Cs profile. Peak 239+240Pu and 137Cs activities in the core were 1.60 +/- 0.02 and 47.8 +/- 0.8 Bq/kg, respectively; inventories were 108 +/- 2 Bq/m2 239+240Pu and 2710 +/- 40 Bq/m2 137Cs. Detection limits, based upon the analysis of 20 g samples, were 0.004 Bq/kg 239Pu, 0.012 Bq/kg 240Pu, and 0.012 Bq/kg 239+240Pu. 240Pu/239Pu atom ratios of 0.16-0.19 were obtained for all core intervals containing detectable Pu, which indicates that global fallout is the source of these radionuclides.

Treatment with 3,4,3-LIHOPO of simulated wounds contaminated with plutonium and americium in rat.

The effect of a siderophore analogue 3,4,3-LIHOPO has been investigated in rat after intramuscular injection of 238Pu, 239Pu and 241Am simulating puncture wounds. Various treatment regimens were used to remove the radioactivity from its injection site and to reduce its retention in body tissues. The local deposits could be reduced to 9% of that in untreated controls by a single local injection of 30 mumol kg-1 3,4,3-LIHOPO administered 1 day after the actinides. Tissue retention of radioactivity was most effectively reduced (to 3% of controls) by continuous subcutaneous infusion of 3,4,3-LIHOPO (3 mumol kg-1 day-1), starting immediately after the injection of actinides and continuing for 2 weeks. The administration of 3,4,3-LIHOPO in drinking water was least effective. Treatment efficacy was substantially higher with 238Pu than with an equal activity of 239Pu (the 238Pu mass, however, was almost 300 times lower than that of 239Pu). Accordingly, the biokinetics and removal of 241Am changed when it was injected with 239Pu instead of 238Pu. Continuous infusion of 3,4,3-LIHOPO (3 mumol kg-1 day-1), starting 4 and 30 days after intramuscular injection of 238Pu and 241Am reduced their femoral retention after 1 month to 20 and 60% of controls respectively; whole-body retention of 241Am was reduced to 20 and 70% of controls respectively.

Transfer of 239Pu to mouse fetoplacental tissues.

Cross-placental transfer of 239Pu from the mother to fetus was studied in C3H mice. The activity of 239Pu in the conceptus was measured 24 hrs after the intravenous injection of 239Pu citrate on days 10.5 to 16.5 of gestation. More 239Pu was transferred to the conceptus when the plutonium was administered in the later stages of gestation; 0.12% of the injected dose per conceptus on day 10.5 and 1.3% on day 16.5. In all the gestational stages examined, the yolk sac and decidua contained more than 89% of the total activity distributed in the conceptus. The concentration of 239Pu in the yolk sac was about two orders of magnitude greater than that in the fetus. The 239Pu concentration in the maternal liver decreased with the gestational stage. In the early gestational stages the concentration in the maternal liver was greater than that in the yolk sac; but, this relationship was reversed in the later stages.

Cancer Incidence and Lifespan Vs. Alpha-particle Dose in Beagles

Young adult beagles were injected with graded activities of 239Pu, 241Am, 228Th, 228Ra or 226Ra and observed throughout their lifespans. The vast majority of the dose was from alpha particles. The lifetime incidence of bone sarcoma increased with average skeletal dose, more or less linearly up to high incidence for 239Pu, 241Am, 228Th and 226Ra, but sigmoid fashion for 228Ra. Based on average skeletal dose, the toxicity of the emitters relative to 226Ra = 1.0 was 239Pu = 16.6 +/- 4.5, 241Am = 5.4 +/- 1.6, 228Th = 8.5 +/- 2.3 and 228Ra = 2.0 +/- 0.5. At the lowest doses, the average lifespans were 97% +/- 3% of that in the controls. If beneficial effects occurred, they may have been overwhelmed by the destructiveness of the densely ionizing alpha particles. A cell nucleus 5 micron in diameter receives a mean dose of about 1 Gy (100 rad) when traversed by a single alpha particle. We found no evidence that alpha-particle doses suppressed cancer or lengthened lifespan in beagles.

Man-made plutonium in freshwater and marine environments

Significant concentrations of plutonium isotopes are found in lake and coastal marine sediments accumulating at rates of 1–5 mm/yr. The activity levels of239, 240Pu range between 0·7–3·3 dpm/g for post 1960 sediments. The measured and the calculated integrated activities of239Pu in the lake sediments are in agreement. This suggests that plutonium is chemically reactive in freshwater environments and it is removed to sediments from the water column shortly after its injection.