Initial Criticality Tests

This section identifies those commissioning tests that are performed following completion of the pre-operational commissioning but prior to initial criticality testing. These tests include those performed prior to core load to verify that the plant is ready for core loading, the loading of the core and the tests performed under hot conditions after the core has been loaded but prior to initial criticality. 

Following successful completion of the initial criticality tests, low power tests are conducted, typically at power levels less than 5 %, to measure physics characteristics of the reactor system and to verify the operability of the plant systems at low power levels. These tests are described in detail in Section 14.2. 10.3 of the EDCD (Reference 10.3 and identified below ... 

Stage B fuel loading tests, initial criticality tests and low power tests ... 

Tables 2.1 and 2.2 show that theory enables detonation velocities to be calculated in close agreement with those observed experimentally. This, unfortunately, is not a critical test of the theory as velocities when calculated are rather insensitive to the nature of the equation of state used. A better test would be to calculate the peak pressures, densities and temperatures encountered in detonation, and compare these with experimental results. The major difficulties here are experimental. Attempts to measure temperatures in the detonation zone have not been very successful, but better results have been obtained in the measurement of densities and pressures. Schall introduced density measurement by very short X-ray flash radiography and showed that TNT at an initial density of 1 -50 increased 22% in density in the detonation wave. More recently detonation pressures have been measured by Duff and Houston using a method (introduced by Goranson) in which the pressure is deduced from the velocity imparted to a metal plate placed at the end of the column of explosive. Using this method, for example, Deal obtains the detonation pressures for some military explosives recorded in Table 2.3. More...

In the initial phase of the process (...), the scientist works through the imagination, as does the artist. Only afterwards, when critical testing and experimentation come into play, does science diverge from art...]... 

A detailed comparison of the predictions of these models with direct observations of the minerals present in dust from the primitive asteroids and comets provides a critical test of the accuracy of the presumed starting composition. For example, the effect of raising the C/O ratio in the initial composition results in some of the oxide and silicate minerals being replaced by carbides and carbonates (as discussed by Lodders 2003 Ebel 2006 and references therein). 

For their study Tanford et al. have chosen aqueous 6 M guanidine hydrochloride - -0.1 M mercaptoethanol (to rupture disulfide bonds and to prevent their formation by oxidation of tliiol groups) as denaturing solvent medium. As the initial and most critical test of random coil behaviour, hydrodynamic measurements were carried out on a number of proteins dissolved in the above-mendioned medium. 

The U.S.-based pharmaceutical company William S. Merrell, Inc., licensed thalidomide from its German manufacturer, Chemie Griinenthal, in 1958. After carrying out laboratory, animal, and initial human tests, the company submitted an application to the FDA for marketing authorization. Frances Kelsey, the medical officer assigned to review the application, found deficiencies in the animal studies and criticized the company s testing methods.20 She then requested additional toxicity tests, putting the application on hold. 

JAEA has developed the HTTR, a 30 MWt engineering test HTGR [ 1]. Since the initial criticality... 

There are several reasons to work with dilute solutions of enzyme. First, there is the obvious practical issue of conserving what is often a precious supply of enzyme that has been obtained with some labor and cost. Second, dilution can aid in eliminating unwanted interactions, thereby linearizing the rate vs enzyme curve as described above. Finally, it may be difficult to make measurements of initial rates in steady state unless the enzyme preparation is sufficiently dilute. If too much substrate is converted in the time required to make the measurement, then one must slow the reaction, and this is typically done by reducing the amount of enzyme in the assay. Transient kinetic methods typically require the use of concentrated enzyme solutions. Hence, these methods are seldom used until after basic understanding of the reaction mechanism has been obtained through steady-state kinetic methods, and critical tests can be designed to elucidate further the mechanism by transient kinetic methods. 

PRE STE REA SSURIZER AM GENERATOR (PRIMARY COOLANT SIDE) CTOR VESSEL PRIOR TO INITIAL CRITICALITY. CTOR VESSEL AFTER START OE LOW POWER HYSICS TEST (t = a +45T) CTOR VESSEL AFTER START OF POWER ANGE OPERATIONS + 40T (10 CFR 50, APPENDIX G ... 

The experimental fast reactor JOYO at the Japan Nuclear Cycle Development Institute s Oarai Engineering Center attained initial criticality in April 1977 and was the first liquid metal cooled fast reactor in Japan. From 1983 to 2000, JOYO operated with the MK-II core as an irradiation test bed to develop the fuels and materials for future Japanese fast reactors. Thirty-five duty cycle operations and thirteen special tests with the MK-II core were completed by June 2000 without any fuel pin failures or serious plant trouble. The reactor is currently being upgraded to the MK-III core. This paper provides a review of the operational experiences obtained through the JOYO s operation. 

Through the successful completion of subsequent detailed design, construction, and safety test, the KALIMER will reach initial criticality by the year 2011. 

On the prototype reactor Monju, the initial criticality was achieved in April 1994 and the start-up tests are in progress. The reactor power has been increased gradually from February 1995. Generation of electric power and connection to the grid will be started in July 1995. 

Initially, a UF system was fabricated for static critical tests at lASL. The system was designed to supply UF at temperatures of 300 to 400 K and pressures up to 4 atm to a double-walled aluminum reactor core canbter assembly. The dynamic reactivity characteristics of the system were dete mined by imposing step changes in temperature and pressure. 

Following construction and installation testing, pre-operational commissioning is performed to demonstrate that equipment and systems perform in accordance with design criteria so that initial fuel loading, initial criticality and subsequent power operation can be safely undertaken. Pre-operational tests at elevated pressure and temperature are referred to as hot functional tests. 

Tests performed after iititial fuel loading but prior to initial criticality ... 

Tests related to initial criticality and those performed at low power <5% ... 

Initial fuel loading and subsequent initial criticality and power ascension to full licensed power are performed during the start-up commissioning. Prior to the initiation of these operations, the systems and conditions necessary to bring the plant into compliance with the Tech-Specs (Chapter 16 of the EDCD, Reference 10.3 must be operable and satisfied. These operations are performed in a controlled and safe manner by using test procedures that specify ... 

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