Carbon -14 & Tritium Furnace (MTT) 0 pages

Carbolite/AEA Technology Combustion Furnace for Carbon-14 and Tritium nalysis Tritium (Ihc third and radioactive isotope of hydrogen) and Carbon-14 are included in the NIKKX priorily list of notifiable radionuclides for waste destined for storage cither at their site of origin or al Ihe DRIGG sloragc arca in Cumbria- Hcncc the demand for the analysis of th(se two isotopes in decommissioning wastes lias sleadily risen in rcent ycars. In additionT tritium (as tritiated water) and Carbon* 14 are discharged to the environment from nuclear oprations, so therc is also a demand for the analysis of environmental matcrials for Ihcsc two nuclides. The only applicable analytical technique is to combust the sample to completion, aided by a suitablc calalyst, and selectively Irap the chief combustion products, ie carbon dioxide and water. The concentration of the Carbon-14 and tritium (tritiated water) in the trapping agents would then be assessed by liquid scintillation counting and thereby the sample tritium and Carbon-14 concentrations can be calculatcd. Th驨se findings prompted the design and building of Ihc Carbolite/AEA Technology combustion furnace, with the following important be nef its. The sample combustion tube is of a convcntional type and is not an intgral part of the furnace, hcncc replacement is achieved quickly and easily without the need for expensive refurbishmeitt and avoids excessive instrument *down~timcr. The sample combustion tube, gas bubblcr train and associated connectors arc fabricatcd cntircly from glass and easily dccontaminaled, thereby avoiding analytical 'mcmory'cffccls. The sample combustion tube and associated glassware are relatively inexpensive and therefore replicate sets can easily be kept and used for diffrent classes of sample. So a particular furnace can easily be used to analyse a diverse range of matcrials, ranging from those of an environmental origin to those gencrated by decommissioning op驩rations, The Carbolite/AEA Technology furnace incorportes a uniquely designed manifold which permils oxygen to be delivered to the calalyst to operate at its optimum at ail stages of the sample combustion. In addition, sinec the gas delivery tube runs through the healed calalyst there is no possibility of thermal dcomposition products *condensing ouf on the outside surface of the gas delivery tube. The oxygen is also ejected at right angles to the main gas flow therefore reducing opportunities for the 'back flow* of sample combustion gases/products into the gas delivery tube. The temp⩩rature control of the sample zone can bc programmed via a comm linked PC This has the advantage that diffrent sample combustion protocols can be created and conveniently stored on dise. Thse can then be retrieved and downloadcd to the furnace as and when reqtiired. The COMMS outputs from a number of furnaces can bc 4daisy-chaincd* together to a single PC hence permitting their individual op騩ration, each can bc running a diffrent protocole from a single PC or workstation. Thts would also allow a furnace and its associated equipmenl to be placcd in a hazardous environment and operated remotely if so required.