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GROUNDING OF BETA SOURCES BY AN AUXILIARY ALPHA SOURCE

Description: A Po/sup 210/ source was used to furnish a reliab1e ground for both electron and positron sources. This was done to prevent the electron and positron sources from charging during BETA spectral studies in magnetic lens spectrometers. An approximately 20- mu c Po/sup 210/ source was placed 1.2 in. behind a 4- mu c Na/sup 2 / 2>s positron emitter backed by 20- mu g/cm/sup 2/ Formvar in the spectrometer; this arrangement resulted in a charging rate decrease of approximately 80%. When the source was placed 0.5 in. away, no charging was detectable over a period of more than one week. The discharge is attributed mainly to the loss of electrons from the source and backing caused by ionization of alpha particles since few alpha particles are stopped near the source. (B.O.G.)
Date: December 1, 1960
Creator: Nichols, R.T. & Jensen, E.N.
Partner: UNT Libraries Government Documents Department

SMALL-ORDER SHAPE FACTORS IN In$sup 114$, P$sup 32$, AND Y$sup 9$$sup 0$

Description: The beta spectra of In/sup 114/, P/sup 32/, and Y/sup 90/ were stud ied closely in an intermediate-image beta-ray spectrometer and compared to theoretical predictions in terms of a linear shape factor of the form (1 + aW). The values obtained for a were s for P/sup 32/, and (-0.0047 plus or minus 0.0008)/mc/sup 2/ for Y/sup 90/, all for electron kinetic energies from about 200 kev up to near the maximum beta energies. Tests were made to give indications for spectrometer fidelity. Because of the linearity of the shape-factor plots and the similarity in energy range, the comparative results from In/sup 114/, P/ sup 32/, and Y/sup 90/ are tak en as a definite indication that for at least two of these activities the shape factors have nonzero slopes, irrespective of questions of instrumental fidelity. (auth)
Date: April 1, 1961
Creator: Nichols, R.T.; McAdams, R.E. & Jensen, E.N.
Partner: UNT Libraries Government Documents Department

A demonstration experiment of steam-driven, high-pressure melt ejection

Description: A steam blowdown test was performed at the Surtsey Direct Heating Test Facility to test the steam supply system and burst diaphragm arrangement that will be used in subsequent Surtsey Direct Containment Heating (DCH) experiments. Following successful completion of the steam blowdown test, the HIPS-10S (High-Pressure Melt Streaming) experiment was conducted to demonstrate that the technology to perform steam-driven, high-pressure melt ejection (HPME) experiments has been successfully developed. In addition, the HIPS-10S experiment was used to assess techniques and instrumentation design to create the proper timing of events in HPME experiments. This document discusses the results of this test.
Date: August 1, 1990
Creator: Allen, M.D.; Pitch, M. (Sandia National Labs., Albuquerque, NM (USA)) & Nichols, R.T. (Ktech Corp., Albuquerque, NM (USA))
Partner: UNT Libraries Government Documents Department

Experiments to investigate direct containment heating phenomena with scaled models of the Surry Nuclear Power Plant

Description: The Containment Technology Test Facility (CTTF) and the Surtsey Test Facility at Sandia National Laboratories are used to perform scaled experiments that simulate High Pressure Melt Ejection accidents in a nuclear power plant (NPP). These experiments are designed to investigate the effects of direct containment heating (DCH) phenomena on the containment load. High-temperature, chemically reactive melt (thermite) is ejected by high-pressure steam into a scale model of a reactor cavity. Debris is entrained by the steam blowdown into a containment model where specific phenomena, such as the effect of subcompartment structures, prototypic air/steam/hydrogen atmospheres, and hydrogen generation and combustion, can be studied. Four Integral Effects Tests (IETs) have been performed with scale models of the Surry NPP to investigate DCH phenomena. The 1/61{sup th} scale Integral Effects Tests (IET-9, IET-10, and IET-11) were conducted in CTRF, which is a 1/6{sup th} scale model of the Surry reactor containment building (RCB). The 1/10{sup th} scale IET test (IET-12) was performed in the Surtsey vessel, which had been configured as a 1/10{sup th} scale Surry RCB. Scale models were constructed in each of the facilities of the Surry structures, including the reactor pressure vessel, reactor support skirt, control rod drive missile shield, biological shield wall, cavity, instrument tunnel, residual heat removal platform and heat exchangers, seal table room and seal table, operating deck, and crane wall. This report describes these experiments and gives the results.
Date: June 1, 1994
Creator: Blanchat, T. K.; Allen, M. D.; Pilch, M. M. & Nichols, R. T.
Partner: UNT Libraries Government Documents Department

Experiments to investigate direct containment heating phenomena with scaled models of the Zion Nuclear Power Plant in the Surtsey Test Facility

Description: The Surtsey Facility at Sandia National Laboratories (SNL) is used to perform scaled experiments that simulate hypothetical high-pressure melt ejection (HPME) accidents in a nuclear power plant (NPP). These experiments are designed to investigate the effect of specific phenomena associated with direct containment heating (DCH) on the containment load, such as the effect of physical scale, prototypic subcompartment structures, water in the cavity, and hydrogen generation and combustion. In the Integral Effects Test (IET) series, 1:10 linear scale models of the Zion NPP structures were constructed in the Surtsey vessel. The RPV was modeled with a steel pressure vessel that had a hemispherical bottom head, which had a 4-cm hole in the bottom head that simulated the final ablated hole that would be formed by ejection of an instrument guide tube in a severe NPP accident. Iron/alumina/chromium thermite was used to simulate molten corium that would accumulate on the bottom head of an actual RPV. The chemically reactive melt simulant was ejected by high-pressure steam from the RPV model into the scaled reactor cavity. Debris was then entrained through the instrument tunnel into the subcompartment structures and the upper dome of the simulated reactor containment building. The results of the IET experiments are given in this report.
Date: May 1, 1994
Creator: Allen, M. D.; Pilch, M. M.; Blanchat, T. K.; Griffith, R. O. & Nichols, R. T.
Partner: UNT Libraries Government Documents Department

Experimental results of direct containment heating by high-pressure melt ejection into the Surtsey vessel: The DCH-3 and DCH-4 tests

Description: Two experiments, DCH-3 and DCH-4, were performed at the Surtsey test facility to investigate phenomena associated with a high-pressure melt ejection (HPME) reactor accident sequence resulting in direct containment heating (DCH). These experiments were performed using the same experimental apparatus with identical initial conditions, except that the Surtsey test vessel contained air in DCH-3 and argon in DCH-4. Inerting the vessel with argon eliminated chemical reactions between metallic debris and oxygen. Thus, a comparison of the pressure response in DCH-3 and DCH-4 gave an indication of the DCH contribution due to metal/oxygen reactions. 44 refs., 110 figs., 43 tabs.
Date: August 1, 1991
Creator: Allen, M.D.; Pilch, M.; Brockmann, J.E.; Tarbell, W.W. (Sandia National Labs., Albuquerque, NM (United States)); Nichols, R.T. (Ktech Corp., Albuquerque, NM (United States)) & Sweet, D.W. (AEA Technology, Winfrith (United Kingdom))
Partner: UNT Libraries Government Documents Department

Experiments to investigate the effect of flight path on direct containment heating (DCH) in the Surtsey test facility

Description: The goal of the Limited Flight Path (LFP) test series was to investigate the effect of reactor subcompartment flight path length on direct containment heating (DCH). The test series consisted of eight experiments with nominal flight paths of 1, 2, or 8 m. A thermitically generated mixture of iron, chromium, and alumina simulated the corium melt of a severe reactor accident. After thermite ignition, superheated steam forcibly ejected the molten debris into a 1:10 linear scale the model of a dry reactor cavity. The blowdown steam entrained the molten debris and dispersed it into the Surtsey vessel. The vessel pressure, gas temperature, debris temperature, hydrogen produced by steam/metal reactions, debris velocity, mass dispersed into the Surtsey vessel, and debris particle size were measured for each experiment. The measured peak pressure for each experiment was normalized by the total amount of energy introduced into the Surtsey vessel; the normalized pressures increased with lengthened flight path. The debris temperature at the cavity exit was about 2320 K. Gas grab samples indicated that steam in the cavity reacted rapidly to form hydrogen, so the driving gas was a mixture of steam and hydrogen. These experiments indicate that debris may be trapped in reactor subcompartments and thus will not efficiently transfer heat to gas in the upper dome of a containment building. The effect of deentrainment by reactor subcompartments may significantly reduce the peak containment load in a severe reactor accident. 8 refs., 49 figs., 6 tabs.
Date: October 1, 1991
Creator: Allen, M.D.; Pilch, M.; Griffith, R.O. (Sandia National Labs., Albuquerque, NM (United States)) & Nichols, R.T. (Ktech Corp., Albuquerque, NM (United States))
Partner: UNT Libraries Government Documents Department