Radioactive constituents

Plasma gasification is a generic-type process that can accommodate virtually any input waste material in as-received condition, including liquids, gases, and solids in any form or combination. Also, moisture content is not a problem. Liquids, gases, and small particle-size waste materials are very easily and efficiently processed. Bulky items, such as household appliances, tires, and bedsprings, can also be readily accommodated without loss of destruction efficiency. The reactor vessel and waste feed mechanism are designed for the physical characteristics of the input waste stream. Even waste materials such as low-level radioactive waste can be processed to reduce the bulk and encapsulate the radioactive constituents to reduce leachability. 

It is good that we should be concerned about the environmental impact of what we, as chemists, do to our planet. But many environmental campaigners too easily confuse radioactive toxicity and chemical toxicity. For example, the radon gas emanating from naturally occurring granite rocks is chemically inert, because it is a rare gas, but it is toxic to humans because of its radioactivity. Conversely, sodium cyanide contains no radioactive constituents yet is chemically toxic. 

The Lockheed Corporation, now Lockheed Martin, has designed, constructed, and operated batch and continuous ex situ treatment facilities for acid extraction of contaminants. This technology involves the solubilization of contaminants, followed by the isolation of soluble elements into appropriate forms. The goal of this technology is to minimize the volume of hazardous and radioactive constituents for disposal. Physical separation techniques may be used as pretreatment steps. 

To remove radium and other radioactive constituents from pitchblende, Hahn and Meitner treated pulverized pitchblende repeatedly and for long periods of time with hot concentrated nitric acid. From the insoluble siliceous residue they separated a new radioactive substance, which they called protoactinium. This name has subsequently been shortened to protactinium. When they added a little tantalum salt to a solution containing protactinium, the reactions of the new substance so closely resembled those of tantalum that Hahn and Meitner were unable to separate the two substances (118). Since tantalum is not radioactive, the protactinium could thus be obtained free from other radioelements. Since protactinium is not an isotope of tantalum, it should be possible to separate them from each other (119). By working up large quantities of rich pitchblende residues from the Quinine Works at Braunschweig, Hahn and Meitner were able to extract more active preparations of the new element (49). 

Maximum difficulty to recover radioactive constituents from waste form (especially fissile materials, such as Pu). 

This paper presents the more important data and conclusions from three reports which describe the uptake behavior of the vaporized oxides of molybdenum, tellurium, and rubidium by molten and solid substrates at high temperatures (I, 2, 3). These oxides were used as the vapor species because of their relatively high volatility and because of their importance as radioactive constituents, or the precursors of important constituents, of radioactive fallout particles. 

The definition of solid waste in RCRA specifically excludes source, special nuclear, and byproduct materials as defined in AEA. Therefore, radioactive constituents of wastes that arise from operations of the nuclear fuel cycle are excluded from regulation as hazardous waste under RCRA. 

When gross beta particle activity exceeds 50 pCi L radioactive constituents must be identified total body doses must be calculated. 

As in the case of hazardous contaminants discussed in Chapter 16, CBPC treatment converts radioactive constituents of waste streams into their nonleachable phosphate mineral forms. It follows the philosophy [7] that, if nature can store radioactive minerals as phosphates (apatite, monozites, etc.) without leaching them into the environment, researchers should be capable of doing the same by converting radioactive and hazardous... 

The past half-century has witnessed an enormous accumulation of nuclear wastes. This accumulation continues today, but on a smaller scale, due to peacetime uses of nuclear energy. Some of the largest repositories of nuclear waste are derived fi-om atomic weapons development and are found in the USA. These repositories often date back to the 1940s and 1950s and contain a mixture of radioactive and non-radioactive constituents refleeting past efforts to modify the original waste. 

From this mineral it was formerly customary to extract the uranium and discard the residue. The chemical study of such a complex mixture is an exceedingly difficult task, but by patient effort M. and Mme. Curie succeeded > in 1898 in separating two new radioactive substances to which the names radium and polonium were applied. The latter is now commonly called radium F. Later Debieme discovered 2 a third radioactive constituent of pitchblende residues and named the new substance actinium. 

Purkayastha, B.C. and D.K. Bhattcharyya On the investigation of different radioactive constituents present in... 

Table I. Principal Radioactive Constituents Observed After 900 s or NOs as the Nitrogen Sources and Incubated in the...

Table II. Principal Radioactive Constituents Observed After 900 s...

A general method for distinguishing among the radioactive constituents in a sample is to plot the logarithm of total observed activity as a function of time. First, consider a single-component system. Taking the logarithm of Equation 19.S yields... 

Pertechnetate separation is acconqilished using a strongly basic anion exchange resin. The separation selectivity using anion exchange is adequate for the analysis of aged LAW sanqile matrixes and provides reliable separation of pertechnetate from the major radioactive constituents ( Sr/ V, Cs) and the minor constituents (e.g., isotopes of Sn, Sb, and Ru). A combination of column washes using dilute nitric acid, nitric-oxalic acid, sodium hydroxide, and moderately concentrated nitric acid has been developed for reliable separation of pertechnetate from anionic species. 

Efficient dust control because the dust may contain radioactive constituents and emit radon gas. 

A global analysis of all radionuclides, as well as of non-radioactive constituents, can be performed by taking microsamples from the fuel pellet, e. g. by mechanical drilling or by an ultrasonic technique. By using sophisticated sampling techniques, a local resolution on the order of 300 pm is possible. In order to determine the fission gas contents, the microsamples are dissolved under vacuum in de-aerated nitric acid the released gases are collected and analyzed by mass spectrometry. Other constituents are determined by an appropriate separation and measurement method as an example, determination of in such microsamples by neutron activation analysis is described in Section 3.2.3.3. 

N Springs 1325-N and 1301-N (via soil column) Liquid 0.96 to 1.4 mgd Columbia River NPDES permit WA-000374-3 plus radioactive constituents... 

N Zone I Cell 1 to 5 Gas 120,000 ftVmin 109-N Zone 1 Cell 1 to 6 Vents Radioactive constituents... 

N Zone 1 cell 6 Gas 28,000 ftVmin 109-cell 6 vent Radioactive constituents... 

N Zone 11 Gas 23,000 ftVmin 105/109-N Zone 11 exhaust fan Radioactive constituents... 

N Zone 111 Gas 130,000 ftVmin Zone 111 exhaust fan 10 Radioactive constituents... 

N Zone IV Gas 1,600 ftVmin Zone IV exhaust fans 14 and 15 Radioactive constituents... 

N Transfer Area 105-N Gas 28,000 ftVmin 105-N transfer area exhaust fans Radioactive constituents... 

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