Performance testing of single electrically heated fuel pin simulators for PWR LOCA experiments
Abstract
The Blowdown Heat Transfer Program (PWR-BDHT) uses electrically heated fuel pin simulators in 49-rod bundles in steady-state and transient heat transfer experiments. Prototypical fuel pin simulators representative of the first two bundles have been tested singly for thermal, mechanical, and electrical performance in blowdown experiments in a single-rod loop. Preliminary nondestructive tests were performed on all simulators prior to testing. As a result of the testing program, simulators for two 49-rod bundles were bought. Representative samples of these two groups were tested in the same fashion as were the prototypes. The electrical performance of each tested simulator was excellent. Measured parameters were resistance of the internal heater element and resistance of the BN and MgO insulating materials. The mechanical performances of the simulators were very good with respect to operability and survivability. A disappointing result, however, was that gaps appeared between the inner and outer parts of the dual-walled steel sheaths of bundle 1 prototypes and production heaters; gaps also appeared in bundle 2 heaters, but the magnitudes seemed much smaller. The thermal performances of the simulators were good with the exception of one aspect--repeatability of thermocouple output from one experiment to the next. The gaps in heater sheaths grewmore »
- Authors:
- Publication Date:
- Research Org.:
- Oak Ridge National Lab., TN (USA)
- OSTI Identifier:
- 6741580
- Alternate Identifier(s):
- OSTI ID: 6741580
- Report Number(s):
- ORNL/NUREG-35
TRN: 78-013524
- DOE Contract Number:
- W-7405-ENG-26
- Resource Type:
- Technical Report
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 22 GENERAL STUDIES OF NUCLEAR REACTORS; 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; FUEL PINS; SIMULATION; HEATERS; PERFORMANCE TESTING; PWR TYPE REACTORS; LOSS OF COOLANT; FUEL ELEMENT CLUSTERS; ACCIDENTS; FUEL ASSEMBLIES; FUEL ELEMENTS; REACTOR ACCIDENTS; REACTOR COMPONENTS; REACTORS; TESTING; WATER COOLED REACTORS; WATER MODERATED REACTORS 220900* -- Nuclear Reactor Technology-- Reactor Safety; 210200 -- Power Reactors, Nonbreeding, Light-Water Moderated, Nonboiling Water Cooled
Citation Formats
White, J.D.. Performance testing of single electrically heated fuel pin simulators for PWR LOCA experiments. United States: N. p., 1978.
Web. doi:10.2172/6741580.
White, J.D.. Performance testing of single electrically heated fuel pin simulators for PWR LOCA experiments. United States. doi:10.2172/6741580.
White, J.D.. Mon .
"Performance testing of single electrically heated fuel pin simulators for PWR LOCA experiments". United States.
doi:10.2172/6741580. https://www.osti.gov/servlets/purl/6741580.
@article{osti_6741580,
title = {Performance testing of single electrically heated fuel pin simulators for PWR LOCA experiments},
author = {White, J.D.},
abstractNote = {The Blowdown Heat Transfer Program (PWR-BDHT) uses electrically heated fuel pin simulators in 49-rod bundles in steady-state and transient heat transfer experiments. Prototypical fuel pin simulators representative of the first two bundles have been tested singly for thermal, mechanical, and electrical performance in blowdown experiments in a single-rod loop. Preliminary nondestructive tests were performed on all simulators prior to testing. As a result of the testing program, simulators for two 49-rod bundles were bought. Representative samples of these two groups were tested in the same fashion as were the prototypes. The electrical performance of each tested simulator was excellent. Measured parameters were resistance of the internal heater element and resistance of the BN and MgO insulating materials. The mechanical performances of the simulators were very good with respect to operability and survivability. A disappointing result, however, was that gaps appeared between the inner and outer parts of the dual-walled steel sheaths of bundle 1 prototypes and production heaters; gaps also appeared in bundle 2 heaters, but the magnitudes seemed much smaller. The thermal performances of the simulators were good with the exception of one aspect--repeatability of thermocouple output from one experiment to the next. The gaps in heater sheaths grew as a function of temperatures cycling with resultant increases in thermal resistances across the gaps. This effect diminished with the number of cycles. Other aspects of thermal performance were completely satisfactory: (1) reproducibility of time and location to transient CHF, (2) thermal time constants of thermocouples, (3) proper power profile, and (4) repeatability of heat flux profile.},
doi = {10.2172/6741580},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 01 00:00:00 EDT 1978},
month = {Mon May 01 00:00:00 EDT 1978}
}
-
Analysis of data in large loss-of-coolant accident experimental facilities often requires extensive use of signals recorded from thermocouples embedded in indirectly heated electric fuel pin simulators (EFPS). These signals, converted to temperature, are used in the numerical determination of EFPS experimental conditions, inclusing transient surface temperature, transient surface heat flux, and transient internal radial temperature distribution. Important points that arise in uding the recorded thermocouple signals as a basis for subsequent analysis include (1) the effect of the distance that the thermocouple bead is located from the EFPS surface on the ability of the thermocouple to resolve rapidly changing boundarymore »
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Surface heat flux perturbations in BDHT fuel pin simulators. [PWR]
The perturbation is quantified for the surface heat flux and surface temperature in blowdown heat transfer (BDHT) bundle 1 fuel pin simulators due to the presence of the thermocouple and groove, gaps, heater eccentricity, and power zone breaks. Steady-state and transient-case studies are presented to illustrate the azimuthal and axial variations in the surface conditions. The conceptual designs of BDHT bundle 3 fuel pin simulators are also evaluated. Recommendations are made for improvements in the heater designs and for the development of computer codes to analyze the responses of the heater thermocouples. -
Design concept and testing of an in-bundle gamma densitometer for subchannel void fraction measurements in the THTF electrically heated rod bundle. [PWR]
A design concept is presented for an in-bundle gamma densitometer system for measurement of subchannel average fluid density and void fraction in rod or tube bundles. This report describes (1) the application of the design concept to the Thermal-Hydraulic Test Facility (THTF) electrically heated rod bundle; and (2) results from tests conducted in the THTF.