- Email: [email protected]
Tritium experience at RINS-II
493
Tritium Qerience at RTNS-II C. M. LOGAN, J. C. DAVIS, T. A. GIBSOH, 12. kl. HEIKKINEN, 6. J. -___ SCHUMACHER and MrmmLawrence Livermore Laboratory*, Liver-more, California -- The Rotating Target Neutron Source - Ii (RTNS-II) is the first iecility within the Magnetic Fusion Energy program which routinely handles tritium in order to function. The two accelerator-based neutron sources in this facility are dedicated to fusion materials research. Over 1013 14-MeV neutrons per second are produced by accelerating deuterons to 400 keV and :.ombarding a TiT2 target. Tritium is released from these targets into the accelerator vacuum system. Vacuum pumping is continuous-throughput via turbomolecular/mechanical pumps exhausting to a cer,':raltritium scrubber. The scrubbed exhaust is then released via the facility stack. Tritium :101d-up in turoo pump oil is minor but the inventc;y in mechanical pump oil ‘;s appreciable. On sever;! occasions water has leaked into the accelerator vetuum system. This water conaenses in the vacuum jump exhaust lines with tritium concentrations of several Ci/9.. The largest single exposure resulted frcm spilling of condensate from the vacuum exhaust line. This water is also probably t+e major cause of hold-up in puma oil. Tritium re!ease frown the facility in normal operation with vaiL,um systev! exhaust flowing througn the scrubber is extremely low, < lmCi/day. Tlfe original facility design envisioned direct stacking of pump exhaust during roughing since no tritium gas load would be present. This allowed designing the scrbbbsr foi the modest flow rates required to handle ion source gas load and vacuum system leakage. Exoerience nas snown that pump-down; are the major sour;e of tritium reiease, probably because of tritiated water released 1.~0~: mechanicai pum; oil during high throughput. Release rates as high 3s 5: mCiisec have been observed for a few seconds. Routine target changes have been the cause of most tritium uptak.2 experienceo by oersonnel. Urine concentrations cf 0. 5 - 1.5 uCi/?. are usually obscriea after handling a frest, target. Spillage of colmta.ninatedwater and oil have been the cause of most "hoLsekeeping" problems and trackiny of tritium b.eyor,dthe target and hot work areas. *Work performed under the auspices of I~.CU.S
kpt,
of Energy, Contract W-7405-Eng-48.
Design of a Demonstration Tritium Recovery Plant for Chalk River, T.E. Harrison, Atomic Energy of Canada Limited Research Company, Chalk River, Ontario -- Ontarro Hydro and Atomic Energy of Canada Limited are collaborating on the development of plants to extract tritium from heavy Part of the plan is to construct a tritium recovery plant demonwater. stration (TRPD) at Chalk River Nuclear Laboratories (CRNL). A detailed process flowsheet, process description, material balance, equipment list and a preliminary building layout have been prepared for the TRPD. Extraction capacity is 40 g of elemental tritium annually from 16 kg.h-' (150 GBq.kg-l) feedwater. of 4 Ci.Kg-1 The process involves transfer of tritium from the heavy water stream to a deuterium gas stream, followed by fractional distillation of the gas stream at 25 K. An existing helium refrigerator will be modified to supply the cryogenic requirement of Transfer of tritium from water to gas is accomplished 5000 watts a,t 20 K. by liquid phase catalytic exchange (LPCE), using a wet-proofed catalyst developed at COWL. The process is designed to isolate the fire and explosion hazard 'of deuterium from the radiological hazard of tritium. The tritium enrichment factor in the first of two distillation columns is less than 5 times limited to 25, giving an average tritium concentration that in the plant feedwater. The second column is tapered to minimize tritium holdup. Equipment is provided for converting DT to tritium and for bottling the tritium product. A cold box provides secondary containment for the distillation columns. Other high tritium equipment is located in nitrogen-purged gloveboxes, but any tritium that leaks out of the process equipment will not be recovered.
Tritium Qerience at RTNS-II C. M. LOGAN, J. C. DAVIS, T. A. GIBSOH, 12. kl. HEIKKINEN, 6. J. -___ SCHUMACHER and MrmmLawrence Livermore Laboratory*, Liver-more, California -- The Rotating Target Neutron Source - Ii (RTNS-II) is the first iecility within the Magnetic Fusion Energy program which routinely handles tritium in order to function. The two accelerator-based neutron sources in this facility are dedicated to fusion materials research. Over 1013 14-MeV neutrons per second are produced by accelerating deuterons to 400 keV and :.ombarding a TiT2 target. Tritium is released from these targets into the accelerator vacuum system. Vacuum pumping is continuous-throughput via turbomolecular/mechanical pumps exhausting to a cer,':raltritium scrubber. The scrubbed exhaust is then released via the facility stack. Tritium :101d-up in turoo pump oil is minor but the inventc;y in mechanical pump oil ‘;s appreciable. On sever;! occasions water has leaked into the accelerator vetuum system. This water conaenses in the vacuum jump exhaust lines with tritium concentrations of several Ci/9.. The largest single exposure resulted frcm spilling of condensate from the vacuum exhaust line. This water is also probably t+e major cause of hold-up in puma oil. Tritium re!ease frown the facility in normal operation with vaiL,um systev! exhaust flowing througn the scrubber is extremely low, < lmCi/day. Tlfe original facility design envisioned direct stacking of pump exhaust during roughing since no tritium gas load would be present. This allowed designing the scrbbbsr foi the modest flow rates required to handle ion source gas load and vacuum system leakage. Exoerience nas snown that pump-down; are the major sour;e of tritium reiease, probably because of tritiated water released 1.~0~: mechanicai pum; oil during high throughput. Release rates as high 3s 5: mCiisec have been observed for a few seconds. Routine target changes have been the cause of most tritium uptak.2 experienceo by oersonnel. Urine concentrations cf 0. 5 - 1.5 uCi/?. are usually obscriea after handling a frest, target. Spillage of colmta.ninatedwater and oil have been the cause of most "hoLsekeeping" problems and trackiny of tritium b.eyor,dthe target and hot work areas. *Work performed under the auspices of I~.CU.S
kpt,
of Energy, Contract W-7405-Eng-48.
Design of a Demonstration Tritium Recovery Plant for Chalk River, T.E. Harrison, Atomic Energy of Canada Limited Research Company, Chalk River, Ontario -- Ontarro Hydro and Atomic Energy of Canada Limited are collaborating on the development of plants to extract tritium from heavy Part of the plan is to construct a tritium recovery plant demonwater. stration (TRPD) at Chalk River Nuclear Laboratories (CRNL). A detailed process flowsheet, process description, material balance, equipment list and a preliminary building layout have been prepared for the TRPD. Extraction capacity is 40 g of elemental tritium annually from 16 kg.h-' (150 GBq.kg-l) feedwater. of 4 Ci.Kg-1 The process involves transfer of tritium from the heavy water stream to a deuterium gas stream, followed by fractional distillation of the gas stream at 25 K. An existing helium refrigerator will be modified to supply the cryogenic requirement of Transfer of tritium from water to gas is accomplished 5000 watts a,t 20 K. by liquid phase catalytic exchange (LPCE), using a wet-proofed catalyst developed at COWL. The process is designed to isolate the fire and explosion hazard 'of deuterium from the radiological hazard of tritium. The tritium enrichment factor in the first of two distillation columns is less than 5 times limited to 25, giving an average tritium concentration that in the plant feedwater. The second column is tapered to minimize tritium holdup. Equipment is provided for converting DT to tritium and for bottling the tritium product. A cold box provides secondary containment for the distillation columns. Other high tritium equipment is located in nitrogen-purged gloveboxes, but any tritium that leaks out of the process equipment will not be recovered.