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Title: Wire Wrapped Hexagonal Pin Arrays for PWR Service

Abstract

The overall hydride project evaluates both hydride (UZrH1.6) and oxide (UO{sub 2}) -fueled cores, with grid spacers and wire-wrapped spacers, over a range of geometries. Steady-state and transient thermal hydraulic analyses yield the maximum power, while fuel performance and neutronics studies provide the achievable discharge burnup. The final optimization integrates the outputs from these separate studies into an economics model to identify the geometry, fuel type, and spacer type that offers the lowest cost of electricity. This work focuses on the steady-state and transient thermal hydraulic as well as economic analyses for PWR cores utilizing wire wraps in a hexagonal array with UZrH1.6 and UO{sub 2}. Design limits were placed on the pressure drop, critical heat flux (CHF), vibrations, and fuel and cladding temperature. Vibrations limits were imposed on the wire-wrapped assemblies for flow induced vibrations (FIV) and thermal hydraulic vibrations (THV). An analysis of the fretting wear of wire wraps indicated that wire wraps out-performed the analogous fretting wear analysis for grid spacers. A CHF study found wire wraps to out-perform grid spacers. Through all of these analyses, it was determined that the thermal hydraulic performance of UZrH1.6 and UO{sub 2} are very similar. Wire wrap cores were foundmore » to have substantially higher maximum powers than grid spacer cores, allowing for a {approx}54% power up-rate due to improved vibrations, pressure drop, and CHF performance. The steady-state and transient analyses were combined with fuel performance and neutronic studies into an economics model that determines the optimal geometries for incorporation into existing PWRs. Results presented herein show cost savings for up-rates with wire wraps over grid spacers of at least 0.8 mils/kWe-hr, or 4%, due to power increases predicted by the thermal hydraulic analyses. Wire wrap UZrH1.6 has a COE savings over wire wrap UO{sub 2} of 0.7 mils/kWe-hr, or 4%. Based on specific assumptions that may be favorable to up-rates, cost savings of up to 10.9 mils/kWe-hr, or 40%, can be achieved with a UZrH{sub 1.6} wire wrap up-rate instead of building a new conventional core. (authors)« less

Authors:
 [1]; ;  [2]
  1. General Electric Company, 3901 Castle Hayne Rd., Wilmington, NC 28401 (United States)
  2. Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
Publication Date:
Research Org.:
American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
OSTI Identifier:
21020996
Resource Type:
Conference
Resource Relation:
Conference: 2006 International congress on advances in nuclear power plants - ICAPP'06, Reno - Nevada (United States), 4-8 Jun 2006; Other Information: Country of input: France; 16 refs; Related Information: In: Proceedings of the 2006 international congress on advances in nuclear power plants - ICAPP'06, 2734 pages.
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; CRITICAL HEAT FLUX; ECONOMIC ANALYSIS; GEOMETRY; NUCLEAR FUELS; PERFORMANCE; PRESSURE DROP; PWR TYPE REACTORS; REACTOR CORES; SPACERS; STEADY-STATE CONDITIONS; THERMAL HYDRAULICS; TRANSIENTS; WEAR; WIRES

Citation Formats

Diller, P, Todreas, N, and Hejzlar, P. Wire Wrapped Hexagonal Pin Arrays for PWR Service. United States: N. p., 2006. Web.
Diller, P, Todreas, N, & Hejzlar, P. Wire Wrapped Hexagonal Pin Arrays for PWR Service. United States.
Diller, P, Todreas, N, and Hejzlar, P. Sat . "Wire Wrapped Hexagonal Pin Arrays for PWR Service". United States.
@article{osti_21020996,
title = {Wire Wrapped Hexagonal Pin Arrays for PWR Service},
author = {Diller, P and Todreas, N and Hejzlar, P},
abstractNote = {The overall hydride project evaluates both hydride (UZrH1.6) and oxide (UO{sub 2}) -fueled cores, with grid spacers and wire-wrapped spacers, over a range of geometries. Steady-state and transient thermal hydraulic analyses yield the maximum power, while fuel performance and neutronics studies provide the achievable discharge burnup. The final optimization integrates the outputs from these separate studies into an economics model to identify the geometry, fuel type, and spacer type that offers the lowest cost of electricity. This work focuses on the steady-state and transient thermal hydraulic as well as economic analyses for PWR cores utilizing wire wraps in a hexagonal array with UZrH1.6 and UO{sub 2}. Design limits were placed on the pressure drop, critical heat flux (CHF), vibrations, and fuel and cladding temperature. Vibrations limits were imposed on the wire-wrapped assemblies for flow induced vibrations (FIV) and thermal hydraulic vibrations (THV). An analysis of the fretting wear of wire wraps indicated that wire wraps out-performed the analogous fretting wear analysis for grid spacers. A CHF study found wire wraps to out-perform grid spacers. Through all of these analyses, it was determined that the thermal hydraulic performance of UZrH1.6 and UO{sub 2} are very similar. Wire wrap cores were found to have substantially higher maximum powers than grid spacer cores, allowing for a {approx}54% power up-rate due to improved vibrations, pressure drop, and CHF performance. The steady-state and transient analyses were combined with fuel performance and neutronic studies into an economics model that determines the optimal geometries for incorporation into existing PWRs. Results presented herein show cost savings for up-rates with wire wraps over grid spacers of at least 0.8 mils/kWe-hr, or 4%, due to power increases predicted by the thermal hydraulic analyses. Wire wrap UZrH1.6 has a COE savings over wire wrap UO{sub 2} of 0.7 mils/kWe-hr, or 4%. Based on specific assumptions that may be favorable to up-rates, cost savings of up to 10.9 mils/kWe-hr, or 40%, can be achieved with a UZrH{sub 1.6} wire wrap up-rate instead of building a new conventional core. (authors)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2006},
month = {7}
}

Conference:
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