LOW-ENERGY NUCLEAR TRANSFORMATION: Where Did the Thorium Go?
By Hal Fox and S-X. Jin
LOW-ENERGY NUCLEAR TRANSFORMATION: Where Did the Thorium Go?
Hal Fox and S-X. Jin
It has been claimed that in a LENT-1 reactor, when operated according to the protocols provided by the Cincinnati Group, that most (over 90%) of a small amount of thorium is transformed into stable elements. Refer to Fig. 1. A solution of thorium nitrate containing a measured amount of thorium (from 0.1 to 0.5 grams) is placed in the zirconium reactor and clamped between TeflonTM seals by using stainless steel end plates. The thorium solution is chemically tested to determine the amount of thorium (4300 parts per million with 0.1 grams of thorium in a 25 ml solution). In addition, a gamma-ray spectroscope (currently using a sodium iodide 2-inch crystal obtained from Ludlum Instruments) is used to provide a spectrum of the gamma-ray emissions from the thorium daughter products. Note: the weak gamma-ray emission from thorium-232 (the mother element) cannot be accurately measured with this gamma-ray equipment. Only the gamma-ray emissions from some of the daughter products can be identified on this type of a sodium-iodide-generated spectra. The spectra of the daughter products is obtained by setting the APTEC software for the Multi-channel analyzer for a specific number of counts (e.g. 100,000 counts). The problem is to provide a low-cost method to follow the thorium and determine to what extent the thorium nuclei are transformed into stable elements.
THE EXPERIMENTAL APPROACH
The thorium solution is processed according to the LENT-1 protocols. The before-processing solution and the after-processing solution are chemically assayed for thorium. A typical report is 4300 parts per million in the before-processing solution and less than 10 parts per million in the after-processing solution. Therefore, we are confident that the thorium has been removed from the processed solution.
The after-processing solution was obtained by allowing any precipitates to settle out of the solution and carefully pouring off the solution. Due to the small amount of precipitates, the precipitates from several experiments were combined and submitted for chemical analysis. The chemical analysis showed that there were 9600 parts per million of thorium in the combined precipitates from five experiments. From the weight of the precipitates, and the concentration of the thorium, it was calculated that 2.57% of the thorium originally introduced into the reactor was present in the precipitates. Now we need only determine where the other 97% of the thorium is located.
Refer to Fig. 1. There is no evidence from gamma-ray analysis to show that any of the thorium daughter products has stuck to the TeflonTM seals. However, it is reasonable to suggest that the thorium has been removed from solution and has somehow stayed on (plated, penetrated, etc.) the cylindrical electrode or onto the disk electrode. Scientists familiar with thorium and zirconium state that the thorium cannot penetrate into the zirconium metal. That professional observation has been taken as a scientific fact.
Experimental observation has shown that the zirconium electrodes erode during the thirty- to sixty-minute processing time. The action of the alternating current applied to the electrodes does form a thin layer of zirconium oxide on each electrode during each anode period. The precipitates are strongly believed to be mainly from the erosion of the zirconium oxide from the two electrodes. The visual evidence shows considerable erosion. For example, if a thin zirconium disk is used, the disk may become so eroded from a thirty-minute processing that the half of the disk immersed in the electrolyte appears lacy where portions have been completely etched or eroded away. Both of the electrodes show evidence of pitting and erosion. The hypothesis is that the transformation of the thorium into stable elements takes place on or in these pits (where charge clusters have been formed and impacted). Because of the erosion of the zirconium electrodes, it is logical to believe that this is not a place where the thorium can accumulate.
[Figure 1. Where is the Thorium?]
Because it is difficult and expensive to make micro-chemical measurements of the electrodes (but planned for the next series of experiments), the following procedure was used: Each of the electrodes was placed in close proximity to the sodium-iodide gamma-ray detector (in essentially the same manner as previously done with both the before-processed solution and the after-processed solution). The APTEC multi-channel analyzer software was set to create a spectra from the same number of total counts as performed previously. In the case of the spectra thus obtained from both electrodes, there was a significant difference in the disk spectra compared with the original solution spectra. The spectral peaks from the daughter products had disappeared or were considerably lower as compared with the spectra (using the same number of counts) of the before-processed solution. The spectra from the after-processing solution exhibited the same features -- a lowering of the counts from the thorium daughter products. Our logical conclusions are the following:
1. At least some of the thorium daughter products have been removed from the processed solution in essentially the same manner that the thorium has been removed from the solution. This is evidenced by the lack of thorium-daughter spectra.
2. Neither the cylinder nor the disk electrode show evidence of "plating out" of the thorium daughter products. The spectra from both the cylinder and disk electrodes show strongly diminished lead-212 counts (as does the post-processed solution). This finding is consistent with the concept and experimental evidence that neither the thorium nor the thorium daughter products have been plated out onto either the disk or cylindrical electrodes.
From the results of a chemical analysis, it is known that the precipitates do contain some thorium. It would, therefore, be expected that the precipitates also contain a proportional amount of the daughter products similar to the amounts found in the initial thorium solution. The spectra of the precipitates (using the same number of counts) show that this is the case. There is little observable difference between the precipitate spectra and the original thorium spectra. It is logical to conclude the following:
3. The small amount of thorium in the precipitates has essentially the same ratio of daughter products as found in the initial before-processing solution. Therefore, the same number of counts should produce gamma-ray spectra that are essentially identical with the initial spectra of the before-processed solution. That conclusion is experimentally observed.
Although, experimental work is encumbered by the use of relatively inexpensive equipment, it is suggested that this gamma-ray spectra approach, used in Trenergy's laboratory, supports the following hypothesis:
In a LENT-1 reactor, using proper protocols, the processing of a weak solution of thorium nitrate will transmute most of the thorium and its daughter products into stable elements. By a combination of gamma-ray spectroscopy and chemical analysis, the proposed (observed) thorium and/or daughter products will be (has been) transformed into new elements.
These experimental observations must be labeled as inconclusive until a careful series of experiments are also subjected to micro-chemical analysis and the new elements identified. Such a plan is the next experimental investigation to be accomplished and reported.
FURTHER REASONING AND OBSERVATION
It is hypothesized that the neutron-rich thorium will produce nuclear fragments that are neutron rich (isotopes lying to the higher neutron end of a line of elemental isotopes) and that such isotopes will decay to stable elements by beta-emission (the changing of a neutron to a proton by the emission of a high-energy electron). By a careful analysis of a chart of nuclides, it is observed that nearly all such nuclear fragments have short half-lives (from less than a second to a few days). It is hypothesized that these nuclear fragments will, therefore, exhibit short-term measurable amounts of gamma-ray emission. It is further hypothesized that specific isotope radioactivity during the beta-emission stabilization processes will be difficult to observe using a sodium-iodide detector. However, some useful experimental measurements can be obtained by observing changes in particle emission immediately following the processing of the thorium solution. For example, it has been determined that the overall particle emission (alpha, beta, and gammas) tends to increase after the completion of processing for a few hours, and then decay over time to near background.
It is further hypothesized that a continuation of the reactor processes after the thorium has been essentially removed from the electrolyte will continue to produce nuclear reactions. It is hypothesized that these nuclear reactions involve elements that are bound to the electrodes, elements from the electrolyte, and also zirconium from the electrodes.
Therefore, equipment that will measure the amounts and energy levels of alpha, beta, and gamma radiation will be useful. However, the ultimate experimental evidence will be the micro-chemical determination of the amount of new elements (not initially present in the solution or in parts of the reactor) that are found in the after-processing solution or in the precipitates.
A high-probability conclusion is that thorium can be transmuted into smaller elements in a relatively inexpensive and low-energy reactor. It is probable that this new technology can be developed into systems that will stabilize some (perhaps much) of the radioactive wastes stored at DOE weapons-related sites and also stabilize the spent fuel pellets stored at various nuclear power plant sites.
Return to the INE Main Page
Feb. 23, 1998.