Reactor instruments

There are three groups of instruments, furnishing information to the operator and to the control system (1) the reactor instruments measuring neutron flux or power level, (2) the rod position and motion indicators, and-(3) the instruments for the auxiliary facilities and energy conversion and storage. These groups will be discussed in the order mentioned. The way in which the instrument signals are presented to the operator, recorded, or used in the control system will be discussed in later sections. 

1 Reactor Instruments, It is necessary to draw a rather arbitrary line separating reactor instruments from instruments on the auxiliary facili ties, particularly the cooling water. Reactor instruments will be understood to include radiation instruments measuring neutron level in the reactor and radioactivity in the water, temperature instruments measuring distribution of exit wa.ter temperature across the active lattice and temperatures in the thermal and biological shields, and pitot tubes measuring distribution of water flow across the bottom (exit) of the active lattice. (See Fig. 5.2.A). 

The reactor radiation instruments are listed in Table 5.2.A. It will be noticed that with one - exception these instruments are located in the reactor. The one. exception, the water monitor chambers, can reasonably be included with the reactor instruments since they monitor water samples from the 37 sampling tubes distributed across the bottom of the active lattice. 

The parallel circular plate (PCP) and compensated ionization chambers and the fission chamber are of ORNL design and manufacture. The air wall and water monitor chambers are made by General Electric Company, and the. boron thermopiles are made by Nuclear Instrument and Chemical Corporation. 

When the MTR was proposed in 1946, the best available ionization.chamber had a useful rangie of about 10. . The development of the compensated ionization chamber with useful range of better than 10 was the first step. Early 

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The Atomic Energy Commission designated Argonne National Laboratory as the first national lab-oratoi-y on July 1, 1946. Ai-gonne was the lead labora-toiy for nuclear reactors, instrumental in designing and building the first nuclear powered submarine, the USS Nautilus in 19.54, and the first nuclear reactor that completely powered the town of Arco, Idaho, m 1955. 

ATR-IR spectroscopy can be used as a spy inside a reactor for on-line monitoring and control of a reaction. The emphasis in this kind of application of ATR spectroscopy is on the detection of reactants and products in the bulk fluid phase. Such applications benefit from the excellent time resolution of FTIR instruments compared to other analytical tools, such as chromatographs. The method can be used in investigations of kinetics of reactions in batch reactors instrumentation has been developed and even commercialized that allows measurements at elevated temperatures and pressures. 

Figure 2 Layout of the Institute Laue Langevin (Grenoble, France) Research Reactor Instrumentation including two cold neutron gnide halls...

The first catalytic cluster ion reaction cycle under thermal conditions was observed by Ervin and coworkers. This group demonstrated that the gas-phase cluster anions Pt (n = 3-7) efficiently catalyze the oxidation of CO to CO2 by N2O or O2 near room temperature in a combined flow tube and gas cell reactor instrument under multicollision conditions [7]. At the end of the process, the intact ciuster is regenerated and each step is exothermic and occurs rapidiy at thermai energies. The observed catalytic reaction cycles are summarized in Fig. 1.81. 

The cost estimate presented last year for the integrated reactor process was reviewed and revised. The cost components with significant revisions were costs of reactor, instrumentation, natural gas and capital recovery. In addition, the costs related to contingency and safety were added. To estimate... 

Reactor Instrumentation categorizes Itself Into three basic classifications. Hie first division can be defined as Reactor Safety Circuit Instrumentation. Instruments In this classification provide Information on the status of the process by visual readout devices auid are connected directly Into the reactor safety circuits for automatic shutdown If preset limits are exceeded. They are responsible for maintaining the stemdards of reactor and nuclear safety at all times. The second category Is Reactor Procet... 

In summary reactor Instrumentation can be categorized Into the following classifications and sub-classlfIcatlons ... 

C. General Functional Criteria For Reactor Instrumentation and Safety Circuit Equipment... 

Obble I, Instrumentation System Classification categorizes and summarizes all ra or reactor instrumentation systems into the classifications per Section II A (Page 11) and shows the power level at which the instrumentation was designed to function (if applicable to a certain power level range.)... 

HW-75010, Power Baoktap Bsquirements for Reactor Instrumentation, B, R. Cremer, et. aX October 1, 1962. 

Letter, H. W. Heacock to S. M. Oraves, Conuaents on HW-750XO, Power Backup Requlrenente for Reactor Instrumentation, October 2 I962. 

MATERIALS TESTING REACTOR INSTRUMENTATION BLOCK DIAGRAM... 

Other Instruments, In addition to the foregoing reactor instruments, all of which measure radiation, there are various temperature and water flow measurements to be mentioned. Each of. the 37 sampling tubes is actually part of a triple-function assembly sampling tube, pitot tube for flow measurement, and thermocouple for water temperature measurement. Knowledge of distribution of water flow velocity and temperature is of obvious value. There... 

Refueling, inspection, and maintenance (RIM) operations require special instrumentation. While the LS-VHTR will have the traditional high-temperature reactor instrumentation, the optically clear characteristics of the salt create new instrumentation possibilities. These are described in Sect. 6. 

After refueling is completed, operations to terminate refueling begin. The process used to terminate refueling is essentially the reverse of that used to prepare for refueling. The upper internals are lowered, control rod drive lines are lowered and reconnected, and the reactor instrumentation is checked out. The equipment hatch is then closed and leak checked, and Ihe reactor is made critical and returned to full power. 

Technical Committee 4S of lEC has as its scope nuclear instrumentation. Subcommittee 4SA deals with reactor instrumentation, while Subcommittee 4SB is concerned with radiation protection instrumentation. A writing group nsoied by Subcommittee 4SB is currently developing a Recommendations for Warning Equipment for Criticality Accidents... 

All experiments require a reactor operator. Some reactor physics experiments (e.g., a critical experiment) will require measurements and data collection in addition to that provided by the existing reactor instrumentation. In this case, a staff member is required to set up and operate the equipment. The reactor operator or another individual must be capable of assuring understanding of the experiment and its results for the students involved. 

Reactor physics experiments that require instrumentation not available in the reactor instrumentation will need some funding for this instrumentation. The cost will depend on level of sophistication desired in the experiment and may vary from US 5000 to US 40 000. 

T he operations personnel will assist the contractor and project forces In running acceptance tests on the plant. This will afford an opportunity to check the validity of preliminary operating procedures. The Initial calibration of much of the reactor Instrumentation will be done by the operating organization. 

IEEE Nuclear Standards http //www.ieee.org/publications standards/index.html (accessed August 25th, 2010). The IEEE has over 130 standards related to nuclear and plasma science, accelerator technology, fusion, nuclear instruments, plasma science and applications, radiation effects, and reactor instruments and controls. 

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