Page 191 - Dynamics and Control of Nuclear Reactors

188 CHAPTER 13 Boiling water reactors

13.14 Advantages and disadvantages
BWRs are sometimes touted as being simpler than PWRs (fewer components,
including no steam generators or pressurizers), operation at lower pressure, and
being well-suited for power maneuvers. The main disadvantage is the need to operate
in a way that avoids instability. Procedures are in place to deal with this problem, but
they certainly represent a departure from simplicity. Also, because steam entering
the turbine contains radioisotopes produced in the core (mainly nitrogen 16), the tur-
bine becomes radioactive and maintenance and repairs are affected, but the radiation
drops rapidly after reactor shutdown. Since N-16 has a half-life of 7.1s, it decays
quickly, permitting safe access to the turbine for maintenance.
BWRs and PWRs are competitors around the world. Since both are in operation
and being built, the relative advantages and disadvantages of these two types must be
viewed as comparable.

Exercises

13.1. Explain why Fig. 13.7 for the feedback phase shift indicates that large feed-
back gains can cause instability.
13.2. Compare the frequency response plots for PWRs and BWRs and discuss the
implications of any major differences.

References

[1] GE Nuclear Energy, BWR-6: General Description of a Boiling Water Reactor.
[2] R.T. Lahey Jr., F.J. Moody, The Thermal-Hydraulics of a Boiling Water Nuclear Reac-
tor, American Nuclear Society, LaGrange Park, 1977.
[3] NRC, General electric advanced technology manual, Chapter 4.3, Power Oscillations,
U.S. NRC, n.d. https://www.nrc.gov/docs/ML1414/ML14140A074.pdf.
[4] J.A. March-Leuba, Dynamic Behavior of Boiling Water Reactors, Doctoral Dissertation,
The University of Tennessee, Knoxville, 1984. available at: http://trace.tennessee.edu/
utk_graddiss/1655.
[5] P.J. Otaduy, Modeling of the Dynamic Behavior of Large Boiling Water Reactor Cores,
PhD Dissertation, University of Florida, 1979.
[6] J.A. March-Leuba, Density-wave instabilities in boiling water reactors, Published as Oak
Ridge National Laboratory Report ORNL/TM-12130 and as U.S. Nuclear Regulatory
Commission report NUREG/CR-6003, October, 1992.
[7] C. Kao, A Boiling Water Reactor Simulator for Stability Analysis, PhD dissertation, The
Massachusetts Institute of Technology, 1996. February.
[8] R. Hu, Stability Analysis of the Boiling Water Reactor: Methods and Advanced Designs,
Doctoral dissertation. MIT, 2010. June.
[9] J. March-Leuba, A reduced-order model of boiling water reactor linear dynamics, Nucl.
Technol. 75 (1986) 15–22.