Nuclear power plant construction returns

InTech, Feb 2007 by Torok, Ray, Naser, Joseph, Sandell, Layla, Harris, Tony

Tending to the instrumentation and control issues for plant deployment is underway

The U.S. nuclear industry is making significant progress toward overcoming financial, regulatory, and technical barriers to deployment of new nuclear power plants.

Progress toward overcoming financial barriers is happening by reducing the uncertainties around capital costs for new nuclear plants.

The Energy Bill of 2005 offers key financial incentives for new nuclear power plant construction in three forms, including loan guarantees, production tax credits, and standby support-risk insurance to cover cost associated with delays that are beyond the control of plant sponsors.

Regulatory barriers are lessening what with efforts to demonstrate the new plant licensing process. The Nuclear Regulatory Commission (NRC, a U.S. government agency) has certified four plant designs, one design application is currently under review, and four other designs have started their pre-application review.

The NRC is also reviewing three utility Early Site Permit applications. Several individual utilities and consortia (groups of utility companies and vendors) are planning to submit Combined Construction & Operating License (COL) applications in 2007-2008, including consortia that have received Department of Energy co-funding to demonstrate the licensing process.

Technical barriers are under the scope of industry research including significant work managed by Electric Power and Research Institute (EPRI).

Specifically, in the instrumentation and control (I&C) area, an industry initiative for new plants was recently started that will identify and prioritize large generic issues, establish resolution paths and schedules, and identify the roles of various stakeholders, including utility companies, EPRI, Nuclear Energy Institute (NEI), vendors, and the NRC.

The initiative addresses I&C issues for both existing and new plants. Here are some key I&C related technical and regulatory issues and their implications for new plants.

New plant reviews more active

There are several unsettled technical and licensing issues in the areas of I&C, human factors, and control rooms that need coordinated, proactive industry attention.

The issues are unsettled in the sense that there is limited guidance and no consensus among utilities, suppliers, and the NRC about what solutions are technically appropriate and would be acceptable in regulatory space.

Some of these issues are already causing protracted regulatory reviews for existing plants, and left untreated, they will likely cause substantial delays and increased costs for new plant COL approvals.

Both industry and the NRC will have roles in resolving the key issues and addressing them in future design efforts and regulatory reviews. Where needed, the industry will want to minimize costs and risks by defining industry consensus solutions with corresponding technical bases.

NEI is forming an industry-working group to coordinate industry efforts and communications with NRC staff. The working group will also help determine priorities and coordinate both new and existing plant resources.

In order to be able to conduct reviews in a timely fashion, the NRC will likely need to enhance and expand staff resources as existing plants upgrade and new plant reviews become more active.

Nine or more combined license applications may go into the NRC in 2007 and 2008. If new plants are to get licenses in a timely, cost-effective manner, the industry and the NRC need to move forward now to develop effective, generic solutions that can work before individual plant COL applications happen.

The following sections explain the most prevalent issues, proposed resolution strategies, and describe the status of ongoing activities to address them.

Technical and regulatory

The issues are in five categories, combining those that involve closely related technical disciplines and resolution approaches.

For all the issues, additional industry and/or regulatory guidance is needed to establish a clear, common understanding in regard to what solutions are technically appropriate and would be acceptable in regulatory space.

While the primary motivation here is to look at issues that could delay new plant approvals, it is important to note these same issues are also relevant for existing plant upgrades, and the technical and regulatory solutions for the two groups should be compatible, if not identical.

To a great extent, these issues flag the need for an overall shift from the analog I&C technology paradigm of existing plants, to the digital paradigm and design approaches that will characterize new plants.

Control rooms and digital control system architectures: New plants will use all or nearly all digital systems for control, communication, and human-system interfaces (HSIs). As a result, they will face a number of issues for which there is limited technical guidance and regulatory precedent. Extensive upgrades to existing plants will test the same issues.

* Licensing digital control rooms: New plants will all use digital control rooms, but no one has built or licensed any in the U.S., and the licensing issues, acceptance criteria, and process are not well defined. For example, what minimum inventory of fixed position and continuously available indicators and controls is appropriate? What technical and regulatory requirements are appropriate for qualified HSIs for accident mitigation, display evaluation, soft controls, computerized procedures, automation, etc? What criteria should apply to assure appropriate teamwork between operating crewmembers and between automation and operators? What types of verification and validation are appropriate for human factors features, and how should their scope and rigor be graded based on complexity and/or safety significance and/or other criteria?