ML20011D763
| ML20011D763 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 07/01/1989 |
| From: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| Shared Package | |
| ML20011D723 | List: |
| References | |
| NUDOCS 8912280378 | |
| Download: ML20011D763 (6) | |
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. ID TABLE OF CONTENTS CHAP 1ER 14 INITIAL RESEARCH AND DEVELOPMENT PROGRAM 14.1 INITIAL RESEARCH AND DEVELOPMENT PROCRAM 14.1.1 DEVELOPMENT PROGRAM OBJECTIVES 14.1.2 DEVELOPMENT PROGRAM SCOPE 14.2 SUBSEQUENT RESEARCH AND DEVELOPMENT PROGRAMS 14.2.1 FUEL RELATED RESEARCH 14.2.2 COBALT PRODUCTION O
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14.1 INITIAL RESEARCH AND DEVELOPMENT PROGRAM 14.1.1 DEVELOPMENT PROGRAM OBJECTIVES One of the initial purposes of the Big Rock Point plant operation was to accommodate a High Power Density Develo; ent Program between the Atomic Energy Commission (AEC) and General Electric Company. The specific objectives of the work performed were as follows:
i Irradiation and examination of high power density, long lifetime fuel fabricated by methods with a potential for low fabrication cost.
Measurements and tests to describe core and nuclear steam supply system performance, to establish reactor operational limits, provide x
means to verify analytical procedures, and support the conceptual X
design of a large high power density reactor (300 MWe).
Installation and operation of a data logging computer system to J
periodically record plant data, compute fuel exposure and plant operational data, and to demonstrate the possible economic advantages of an on-line computer system for a nuclear plant.
14.1.2 DEVELOPMENT PROGRAM SCOPE In order to meet the above objectives, the program provided for
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developmental testing and operation described by the following sub-paragraphs. The areas to be treated therein were (1) fuel
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irradiation and examination, (2) reactor core performance testing, (3) stability and transient performance testing, (4) power distribu-tion and physics testing, and'(5) installation and operation of the T
on-line data logging computer system. None of this developmental j
testing presented unique safety hazards. The testing presented a broader than normal series of performance tests while bringing the I
Big Rock Point reactor to its. ultimate design rating. All operating safeguards criteria were met duriag the testing perJod, and the detailed knowledge of the reactor characteristics provided by this
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Program resulted in lessening any hazard of normal reactor operation.
Fuel bundles fabricated by processes having a potential for low fuel' cost were irradiated and examined.
Performance testr of the Big Roch Point reactor core were conducted.
Steady 7 tate operating Londitions prevailing with a given mode of operat ir.a were measured and evaluated to determine such performance characteristics as burnout safety margin, core exit quality, core and channel flow rates, and core steam void content. These tests were l
conducted simultaneously with other performance tests,' including l
stabilf*y, and covered a range of pressures, recirculation flow l
rates, total reactor power, average power density, and core inlet subcooling. The tests were conducted in a step-wise approach to the
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higher power conditions. The testa consisted of measurements of
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distributions and core pressure drops. Four instrumented assemblies were used to produce detailed fuel channel data. These instrumented assemblies measured fuel channel coolant flow rates, channel and fuel bundle pressure drops, and coolant inlet and outlet temperatures.
3 Neutron flux distribution within the instrumented assemblies was determined both by wire irradiation and with the in-core ion chambers.
Stability and transient performance tests were conducted. Transient recordings of primary system variables under controlled conditions of l
reactor system excitation were analyzed and interpreted to define j
stability margins and load regulation. The excitations imposed included the oscillation of a control rod through a pre-determined I
fixed amplitudes within a range of frequencies from'about 1/60 to about 2 cycles per second. Reactor system response was measured for-an excitation of turbine load demand (up to about 30% load change) and for a disturbance in reactor pressure (up to 50 psi) by changing the pressure regulator setting.
These transient tests were conducted within a series of operating conditions emoracing a defined' range of pressures, recirculation-flow rates, total reactor power, average-power density, and core inlet subcooling. All tests were conducted step-wise, evaluating the trend from previous operating conditions before proceeding to.the next test.
Power distribution and physics tests were conducted. The~ axial power profiles of selected fuel bundlea were measured and the radial power O~
distribution across the core was determined. These tests were performed at prescribed points in the irradiation history of the core and censisted of wire irradiation data and gamma scans of the fuel.
Selected, individual bundles were disassembled and' individual fuel rods were scanned to establish the radial power profiles within a given element.
Physics tests, performed in the cold, xenon free condition, were performed to establish that the reactor is subcritical with one control rod removed, and that the void coefficient'of reactivity is negative for voids produced inside of a new fuel _ bundle. These physics tests were conducted only when changes in core configurations impose substantial changes in core reactivity or control rod worth.
The scheduling computer system, which had no reactor. control or safety function was placed in operation. The computer and its associa*ed equipment was used to measure and convert plant signals, calculate operatire data and parameters, log measured and calculated data, and alarm fa. 2d sensors and out-of-limit operating variables.
Computer system tests which involved specific reactor operating conditions consisted primarily of steady plant operation to evaluate methods and. accuracy of heat rate calculations, xenon reactivity calculations, and neutron flux distribution. Specified variations of control rod patterns were required to evaluate. computer treatment of.
core power distribution and control rod scheduling. All other computer-functions, among which were contrcl rod, fuel, and ion-chamber exposures, and core performance calculation <, vere tested as a part 14.1-2 MI1188-0535A-BX0?
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_of the acrmal operation of the plant. The computer was not required for normal operation of the plant.
It was purchased and operated under AEC Contract.
The computer was subsequently removed in 1984 via Facility Change FC-581.
Details on the Initial Research and Development Program may be obtained by review of the 1961 Final Hazards Summary Report and other docketed submittals.
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i 14.2 SUBSEQUENT RESEARCH AND DEVELOPMENT PROGRAMS 14.2.1 FUEL RELATED RESEARCH s
Research has continued throughout Big Rock Point's operating life.
An important part of that research has been the investigation of fuel-design, in particular the improvement of pellet cladding interaction j
(PCI) behavior. The effects of PCI can limit both the rate of power change and the total power generated (burnup). Extended burnup translates into an economic advantage and conservation of uranium resources.
Consumers Power Company has participated in a fuel performance improvement program (FPIP) with the U.S. Department of Energy and i
Exxon Nuclear Company to develop reactor fuel designs which improve PCI effects. Under the FPIP, standard solid pellet fuel was compared with annular fuel, Vipac fuel, and Sphere pac fuel. Annular fuel pellets are cylindrical with a central hole; Vipac fuel is made up of packed, angular fuel shards; Sphere pac fuel is composed of packed, high-density spherical particles. These fuel types had previously been in other reactors and had shown promise for improving fuel-cladding interaction. The test fuels experienced burnup in the Big Rock Point reactor and were subsequently sent to a reactor in Sweden to undergo elevated power ramp tests.
O It was found that the annular fuel tested at Big Rock Point experi-enced some circumferential cracking at very high ramp rates-resulting in evidence of partial fuel' melting. However, it was believed that operation under typical conditions.would not lead to circumferential cracking and that peak pellet temperatures would be lower than standard pellet fuel. The central holes did fill in with uranium oxide but rocs with annular pellets indicated less cladding strain j
than standard fuel rods.
Sphere-pac fuel rods operated at a tempera-ture about 100*C loser than solid pellet rods under normal operating conditions.
A graphite coating on the interior of the cladding was also-investi-l gated during the FPIP. Evaluations had shown that the graphite coating could serve as a lubricant between the cladding and the fuel.
l Following ramp tests, there was no evidence of graphite remaining on any of the samples.
Big Rock Point has also worked with the U.S. Department of Energy and Exxon Nuclear Company to-investigate extended burnup. Fuel assem-blies are typically discharged from the reactor after an exposure of 27 GWD/MT. As part of the extended burnup program, fuel was utilized in the reactor up to 40 GWD/MT and then analyzed to determine the effects of extended burnup on fuel and cladding. Measurements.taken on fuel with an average exposure of 41 GWD/HT showed the fuel to be in excellent condition with no evidence of accelerated deterioration.
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As a result, future design modifications could allow burnup to exceed
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40 GWD/MT.
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i Mixed-oxide fuels have also been tested at Big Rock Point. Tlue plant's license was amended in 1969 to allow the plant to receive, possess and use uranium-oxide fuel rods containing up to 50 kilograms j
of recycled plutonium. The mixed-oxide R&D program was carried out by Consumers Power Company and General Electric under the sponsorship i
of the Edison Electric Institute.
It was undertaken to evaluate the
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use of plutonium on both a technical and an economic basis. -Nonde-structive surveillance examinations and destructive examinations performed by the Electric Power Research Institute showed that the mixed-oxide rods were very satisfactory and exhibited no unusual cladding or. fuel characteristics.
Consumers Power Company has also implemented various changes in burnable poison concentrations and placement to minimize local i
peaking factors. Fuel enrichment, cladding gap and fuel pressuriza-tion are other parameters which have been varied to improve fuel' performance.
14.2.2 COBALT PRODUCTION For approximately eleven years, Big Rock Point's reactor was employed to produce cobalt-60 sources for use in therapeutic treatment of l
certain cancers.
Irradiation of cobalt material was begun for Neutron Products, Inc., in 196G and was continued until?1982. Over 400 cobalt-60 sources were produced through irradiation at Big Rock Point.
It has been estimated that more than 400,000 people nation-wide received therapeutic treatments from cobalt-60 produced at the plant.
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