Analysis of Credible Accidents for Argonaut Reactors

Five areas of potential accidents have been evaluated for the Argonaut-UTR reactors. They are: • insertion of excess reactivity • catastrophic rearrangement of the core • explosive chemical reaction • graphite fire • fuel-handling accident. A nuclear excursion resulting from the rapid insertion of the maximum available excess reactivity would produce only 12 MWs which is insufficient to cause fuel melting even with conservative assumptions. Although precise structural rearrangement of the core would create a potential hazard, it is simply not credible to assume that such an arrangement would result from the forces of an earthquake or other catastrophic event. Even damage to the fuel from falling debris or other objects is unlikely given the normal reactor structure. An explosion from a metal-water reaction could not occur because there is no credible source of sufficient energy to initiate the reaction. A graphite fire could conceivably create some damage to the reactor but not enough to melt any fuel or initiate a metal-water reaction. The only credible accident involving offsite doses was determined to be a fuel-handling accident which, given highly conservative assumptions, would produce a whole-body dose equivalent of 2 rem from noble gas immersion and a lifetime dose equivalent commitment to the thyroid of 43 rem from radioiodines

Rationale and Architecture Principles for Medical Application Platforms

The concept of “system of systems” architecture is increasingly prevalent in many critical domains. Such systems allow information to be pulled from a variety of sources, analyzed to discover correlations and trends, stored to enable realtime and post-hoc assessment, mined to better inform decisionmaking, and leveraged to automate control of system units. In contrast, medical devices typically have been developed as monolithic stand-alone units. However, a vision is emerging of a notion of a medical application platform (MAP) that would provide device and health information systems (HIS) interoperability, safety critical network middleware, and an execution environment for clinical applications (“apps”) that offer numerous advantages for safety and effectiveness in health care delivery. In this paper, we present the clinical safety/effectiveness and economic motivations for MAPs, and describe key characteristics of MAPs that are guiding the search for appropriate technology, regulatory, and ecosystem solutions. We give an overview of the Integrated Clinical Environment (ICE) – one particular achitecture for MAPs, and the Medical Device Coordination Framework – a prototype implementation of the ICE architecture

General Electric Atomic Power Equipment Department Report GEAP-4385

A research program is being conducted to obtain experimental data in the irradiation of plutonium-enriched fuel to confirm a theoretical model for predicting isotopic composition and reactivity changes in plutonium-enriched, light-water-moderated reactors. Quarterly progress: The densitometry procedure (for measurement of alpha autoradiographs of fuel pellets) has been modified to eliminate the need for a second emulsion. The existence of a problem of latent image fading and non-reciprocity of the high-resolution emulsion has been recognized. A tentative procedure has been worked out to correct these emulsion difficulties. the number of polished pellets has been increased to thirteen. The number of hot spots per pellet has not changed appreciably. The largest spot seen is irregular with an estimated volume equivalent to that of a sphere of 35 mil diameter with a PuO2 concentration in the neighborhood of 60%. The VBWR irradiation run now under way is not scheduled to end until October. To the end of the last run the cumulative exposure reached 3703 MWD/T, as logged by VBWR operating personnel. Applying the same scale factor between logged exposure and Ce-Cs analysis of the first fuel sample gives a corrected exposure of 4416 MWD/T. Further debugging of EPITHERMOS, the epithermal extension of the BNL THERMOS code, is in progress. A flux wire exposure is being prepared to map the thermal neutron spectrum in the neighborhood of the test pins in the program fuel element

General Electric Atomic Power Equipment Department Report GEAP-4482

A research program is being conducted to obtain experimental data in the irradiation of plutonium-enriched fuel to confirm a theoretical model for predicting isotopic composition and reactivity changes in plutonium-enriched, light-water-moderated reactors. Quarterly progress: Forty-six fuel pellet faces have been auto-radiographed. These faces have been prepared from twenty-three pellets by making an exposure before and after the removal of an additional ten mils of fuel. A substantial number of large "hot spots" continue to appear. The largest spot so far observed was 44 mils long, 20 mils wide, and of the order of 20 mils thick. This spot has a PuO2 concentration which varied from 70% on the periphery to 100% at then center. There is some evidence that the segregated regions are elongated with their long axes perpendicular to the direction of the pressing of the green pellet. Determination of the size and concentration distribution is continuing. The EPITHERMOS code now seems to be operating correctly. A test problem for a typical water lattice converged in eleven iterations. The computation of the spectrum for a pure water medium gave results which agreed very well with the expected 1/E spectrum. At the end of the quarter, the program fuel element had received a cumulative total of 4449 MWD/T exposure. This total is as logged by VBWR operating personnel. Applying the same scale factor, between logged exposure and Ce-Ca analysis of the first fuel sample, gives a corrected exposure of 5306 MWD/T. Three sets of flux wires were successfully irradiated at three thimble locations in the project fuel element. Counting is in progress and the data will be reduced in the next quarter. The program fuel element was removed from the VBWR during the November shutdown at the end of run 165 after a cumulative exposure of about 5000 MWD/T. Fuel pin F was removed for analysis, and pin U was moved over into its place. An unirradiated fuel pin, designated M, was inserted in the position vacated by U. The reassembled element was returned and reinserted in the VBWR. The VBWR discontinued operations in December, 1963. The project fuel element was removed from the reactor and placed in storage in the Fuel Storage Building

General Electric Atomic Power Equipment Department Report GEAP-4603

A research program is being conducted to obtain experimental data in the irradiation of plutonium-enriched fuel to confirm a theoretical model for predicting isotopic composition and reactivity changes in plutonium-enriched, light-water-moderated reactors. Quarterly progress: Work has begun in the Radioactive Materials Laboratory to sample the project fuel from the pins irradiated to 1800 and 5000 MWT/T. Some delay has been experienced due to preemption of the hot cells by priority work. Examination of the autoradiographs of the un-irradiated project fuel showed that in a volume of fuel approximately equivalent to a pellet there were 13 hot spots larger than 15 mils. Evaluation of these spots with the fuel analyzer showed that they contained about 14 mg of PuO2 or about 9% of the total present. The EPITHERMOS code is being modified to automatically normalize the epithermal scattering to the correct value for all moderators. Calibration of the flux wires has been made and the reduction of the data from the VBWR irradiation is nearly complete. A similar resonance activation was made in the water reflector of the Stanford Pool Reactor to obtain the relative activity in a well-defined pure water spectrum. Reduction of these data is also in progress

Program for the Development of Plutonium Recycle for Use in Light-Water- Moderated Reactors. Eleventh Quarterly Report, October 1-December 31, 1963

A research program is being conducted to obtain experimental data in the irradiation of plutonium-enriched fuel to confirm a theoretical model for predicting isotopic composition and reactivity changes in plutonium-enriched, light-water-moderated reactors. Autoradiographs of unirradiated fuel indicated approximates 10% microsegregation of the PuO/sub 2/. The irradiations of flux wires and the project fuel element in VBWR are described; the fuel element was removed after approximates 5000 Mwd/t burnup when VBWR operation was stopped in Dec. 1963. Progress on the EPITHERMOS code is described. (D.L.C.

General Electric Atomic Power Equipment Department Report GEAP-4216

A research program is being conducted to obtain experimental data in the irradiation of plutonium-enriched fuel to confirm a theoretical model for predicting isotopic composition and reactivity changes in plutonium-enriched, light-water-moderated reactors. All program efforts have been temporarily deferred except for those associated with the irradiation of the program fuel element in the VBWR. The program fuel element was exposed to a burnup of 465 MWD/T during the quarter which brings the total to 2334 MWD/T. On the basis of the computed isotopic composition, the burnup obtained was 1450 MWD/T

General Electric Atomic Power Equipment Department Report GEAP-4303

A research program is being conducted to obtain experimental data in the irradiation of plutonium-enriched fuel to confirm a theoretical model for predicting isotopic composition and reactivity changes in plutonium-enriched, light-water-moderated reactors. All program efforts have been temporarily deferred except for those associated with the irradiation of the program fuel element in the VBWR. The program fuel element was exposed to a burnup of 831 MWD/T during the quarter which brings the total to 3165 MWD/T. Applying the same scale factor between logged exposure and Ce-Cs analysis of the first fuel sample gives a corrected exposure of 3774 MWD/T

General Electric Atomic Power Equipment Department Report GEAP-4642

A research program is being conducted to obtain experimental data in the irradiation of plutonium-enriched fuel to confirm a theoretical model for predicting isotopic composition and reactivity changes in plutonium-enriched, light-water-moderated reactors. Quarterly progress: Project fuel fins irradiated to 1860, 3000, and 5300 MWD/T have been successfully sampled in the Radioactive Materials Laboratory. The samples have been dissolved and aliquots delivered to Chemistry for Mass Spectrometry and burnup determination. The first Stanford Pool Irradiation indicated that there was some inconsistency in the thermal flux and the near thermal epithermal flux. The experiment was repeated, increasing the number of foil wheel positions from two to three. The data from the second measurement are being reduced. The EPITHERMOS code modification has been completed. Comparisons between the results computed by the code and experimental data show much improved agreement. The metallographic photomicrographs of a polished half-pellet from rod F, irradiated to 5000 MWD/T, show structure very similar to that shown by the pellet from rod S, irradiated to 1860 MWD/T