by Guest Blogger
23. August 2011
This week’s post was written by Dr. Ken Ferguson, an independent consultant evaluating project risk and risk mitigation related to new nuclear reactor projects. He has a PhD in Nuclear Science and Engineering from Carnegie – Mellon University and a B.S. in Physics from the University of Michigan.
The nuclear power industry is committed to safe operations. The recent earthquake and tsunami in Japan reinforces the value of attention to even more effective safety performance from nuclear power reactors. One nuclear technology effort that has promise for such an outcome involves Small Modular Reactor (SMR) designs. Numerous SMR designs are being developed and confirmed which can deliver power levels much lower than the current range of one thousand megawatts offered in nuclear power plants in operation. An additional factor regarding the utilization of SMRs is the directive by the Obama administration for government facilities to have plans by 2020 to reduce their carbon emissions by 80 %. A significant part of this goal can be met by the use of small sized reactors by the Department of Energy and Department of Defense.
Why the attractiveness to the electric utility sector? The fundamental advantage is that the capital outlay and investment for an SMR is billions of dollars less than for a larger reactor. SMR deployment includes adding more modules as time progresses and the actual need for more megawatts is recognized. In a simple economic model, the revenue generated by the first modules help fund the deployment of future modules. In addition, SMR deployment can involve a manufacturing approach rather than on-site construction of larger nuclear plants. This shift has the promise of reducing uncertainty in project completion time that can be experienced in large size nuclear plant projects.
The details of SMR development have important safety features and advantages. A variety of designs are considered to have “passive” safety features in that external actions such as electrical initiation of safety pumps and power sources are not required. Inherent physical behavior such as gravity induced coolant flow and natural circulation of coolant are the basis for safe shutdowns. This basis of safety can also reduce plant cost due to the elimination of certain pumps, valves, electrical wiring, etc.
As with much nuclear technology innovation, an important project risk involves the details of regulatory acceptance and related timing to achieve that acceptance. For SMRs, examples of regulatory action and attentions that need to be accomplished and monitored include:
- Can events in one module impact another module (“common mode failure”)?
- Can one control room operator be allowed to be responsible for more than one module concurrently?
- What is the proper security staffing (many SMR designs are intended to be sited underground)?
- Does an SMR qualify to have a smaller land zone to control during an accident than currently required for larger plants?
- What tests and analyses are needed to properly validate the SMR designs?
- What new regulatory requirements are appropriate to the features of SMR designs?
- What will be the extent of regulatory agencies global cooperation and information exchange on these matters?
