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Published: 1977

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The experiment requirements and objectives for the reactivity initiated accident (RIA) tests to be conducted in the Power Burst Facility (PBF) are described 1n the RIA Experiment Requirements Document (ERD) The primary objectives of the RIA research are to determine fuel failure thresholds, modes and consequences as functions of enthalpy insertion, irradiation history, and fuel design. Coolant conditions of pressure, temperature, and flow rate that are typical of hot-startup conditions in commercial BWRs will be used in the Series 1 tests. The first R!A test outlined in the ERD, RIA 1-1, is to be performed using four test fuel rods (two unirradiated and two irradiated) in the four rod hardware. The test fuel rods are to be exposed to a power transient in PBF which deposits an anergy of about 300 cal/g at 90% of the fuel radius (i.e. near the fuel surface). This will be the first RIA experiment ever perfonned at hot startup conditions and three potential problems have been identified since the ERD was written. These problem areas are: identification of the fuel failure threshold energy deposition for hot-startup conditions, evaluation of calorimetry techniques for RIA transient tests, and determination of possible pressure pulses that can result from fuel failure in a water filled system. Also, recent TREAT test results have indicated that it may be difficult to obtain usable information from some of the instruments planned for use on the Ser1es 1 tests. To resolve the questions raised by the TREAT tests it will be necessary to expose selected instruments to a power burst and monitor their response under adiabatic, constant pressure conditions. Consideration of these potential problems made it clear that an RIA Scoping Test, the subject of this Experiment Specification Document, must be perforrned to resolve thest: potential problems prior to perfonnance of test RIA 1-1. The RIA Scop1ng Test should be comprised of five single rod experiments. The first rod will be subjected to a series of transient power bursts of ever increasing energy reIease to determine the energy deposition failure threshold. The second rod will be subjected to an energy deposition about 50 cal/g less than the energy deposition required for failure during the first test. The third rod will be tested at the failure threshold energy deposition. A calorimetric·power calibration will be performed on the second and third rods for comparison purposes. Rods four and five will be subjected to very high energy depositions (475 and 600 cal/g average energy insertion, respectively) to evaluate pressure pulse generation due to fuel fragmentation at hot-startup conditions. Calorimetric power calibrations will be performed on rods four and five. In the event of unexpectedly large pressure pulse generation for rods four and five it may be necessary to perform additional high energy deposition tests to determine the energy deposition required for fuel dispersal and subsequent pressure pulse generation. The PBF-TFBF singla rod test train or its equivalent will be used for the scoping tests. lnstrumentation for measurement of pressure pulse generation and test rod power will be necessary for the test. To evaluate the effects of radiation on the performance of the fuel rod instrumentation planned for the RlA Series 1 tests, two pressure sensors and an LVDT should be placed in a nearly adiabatic, constant pressure envirorment within the test train and monitored during the bursts. No test rod instrumentation will be required. Results of the Lead Rod Test Series will be used to make preliminary estimates of the transient burst period required.