Effect of Axial Distribution of Gadolinium Burnable Poison in Advanced Pressurized Water Reactor Assembly

Keywords

Advanced Pressurized Water Reactor (APWR), burnable poisons, gadolinium (Gd), burnup, radial power distribution, axial power distribution

How to Cite

Saad, H. M., Refeat, R., Aziz, M., & Mansour, H. (2019). Effect of Axial Distribution of Gadolinium Burnable Poison in Advanced Pressurized Water Reactor Assembly. Nuclear and Radiation Safety, (4(84), 46-53. https://doi.org/10.32918/nrs.2019.4(84).06

Abstract

The radial and axial power distribution in power reactors are determined mainly by the patterns of the fuel assembly and the burnable absorber at the beginning of cycle. In Advanced Pressurized Water Reactor (APWR), gadolinium burnable absorber is used to decrease the relative power of fresh fuel assemblies. In this paper, the effect of the axial distribution of gadolinium (Gd) on the power of the APWR assembly is studied. Three models of APWR assemblies are simulated using MCNP6 code. In the first model, UO2 fuel is distributed uniformly in all the fuel rods. In the other two models some of the UO2 fuel rods are replaced by UO2-Gd2O3 rods in part length distribution. Two gadolinium concentrations 6% and 10% are used. The main neutronic parameters are estimated for the three models: the multiplication factor (K-infinity) as a function of burnup (GWd/MTU), the radial and axial power distributions. The results show that the distribution of the gadolinium absorber in the central region of fuel rod (part-length absorber) leads to flattening of axial power, which means additional axial power distribution control.

https://doi.org/10.32918/nrs.2019.4(84).06

References

1. Design control document for the US-APWR, Chapter 4 Reactor, MUAP- DC004, Rev. 4, August 2013.

2. The document retrieved from http://www.world-nuclear.org/information-library/nuclear-fuelcycle/nuclear-power-reactors/advanced-nuclear-power-reactors.aspx.

3. Mitsubishi fuel design criteria and methodology. MUAP-07008-P-A Rev. 2, (Proprietary) and MUAP-07008-NP-A Rev.2 (Non-Proprietary), July 2013.

4. US-APWR fuel system design evaluation. MUAP-07016-P Rev. 4 (Proprietary) and MUAP-07016-NP Rev. 4 (Non-Proprietary), August 2013.

5. US-APWR fuel system design parameters list. MUAP-07018-P Rev. 0 (Proprietary) and MUAP-07018-NP Rev.0 (Non-Proprietary), December 2007.

6. IAEA-TECDOC-844. Characteristics and use of urania-gadolinia fuels. International Atomic Energy Agency, 1995.

7. Pelowitz, D. B., (2013). MCNP6TM user’s manual. Ver. 1.0, Manual Rev. 0, Los Alamos National Laboratory Report, LA-CP-13-00634, Rev. 0.

8. Goorley, T., et al. (2012). Initial MCNP6 release overview. Nuclear Technology, 180, pp. 298-315.

9. Chadwick, M.B., et.al. (2011). ENDF/B-VII.1: Nuclear data for science and technology: cross-sections, covariances, fission product yields and decay data. Nuclear Data Sheets, 112.

10. Goorley, T. (2014). MCNP6.1.1 beta release notes. LA-UR-14-24680.

11. MCNP5: X-5 Monte Carlo Team, MCNP – Ver. 5, Vol. I: Overview and Theory. LA-UR-03-1987, 2003.

12. Pelowitz, D.B. (2011). MCNPX User’s Manual. Ver. 2.7.0, LA-CP-11-00438.