Ho Nieh
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Ho Nieh

NRR's Director at the U.S. Nuclear Regulatory Commission

"The vast majority of plants in the U.S. already have authorization to operate to 60 years"

The Director of the Office of Nuclear Reactor Regulation (NRR) at the U.S. Nuclear Regulatory Commission, Ho Nieh, considers that “the global nuclear safety community is active and focused on the safety and security”.

What does your work mainly entail and what systems, teams and resources do you use?

The Office of Nuclear Reactor Regulation (NRR) is responsible for the principal licensing and regulation of facilities licensed under the United States’ Atomic Energy Act. These responsibilities include making licensing decisions and maintaining an independent inspection program. I provide leadership and oversight to ensure that NRR’s licensing and inspection programs are conducted in an effective and uniform way. I have a wonderful team of approximately 500 management and staff members who are passionate about protecting the people and the environment.

"We consider risks together with traditional engineering judgment to focus our efforts on those activities that are of greatest significance"

What noteworthy projects are you currently working on?

The Nuclear Regulatory Commission (NRC) has embarked on a journey of change and transformation to become a modern, risk-informed regulator. ‘Risk-informed’ means that we consider risks together with traditional engineering judgment to focus our efforts on those activities that are of greatest significance. By risk-insights, I mean that we seek to answer these three questions: What can go wrong? How likely is it? What are the consequences? In this context, NRR is leading some revolutionary and transformational changes. Examples of these changes include: making our inspection program more risk-informed; improving our licensing processes for advanced fuels that have better accident performance and will allow longer operating cycles; improving our licensing processes to enable more use of digital systems in US nuclear power plants; doing first-of-a-kind licensing reviews of subsequent license renewal applications that would enable licensees to operate a reactor for up to 80 years, and modernizing how we work by introducing new and better technologies. It’s truly an exciting time to be working at the NRC.

"At the present time, 96% of the U.S. reactors are operating under our baseline level of inspection oversight due to their good performance"

How do you rate the safety of US nuclear reactors according to the studies and analyses you conduct at NRC?

Inspectors located throughout our four regional offices inspect and monitor plant performance on a daily basis. Our inspection program is called the Reactor Oversight Process and it uses a combination of inspection findings and performance indicators to determine the level of NRC oversight. I should note that the Spanish nuclear regulatory authority, CSN, has adopted a version of the NRC’s Reactor Oversight Process.

At the present time, 96% of the U.S. reactors are operating under our baseline level of inspection oversight due to their good performance. We spend about three thousand inspection hours at each operating reactor site to do a very thorough look at the performance of each site and to ensure that any problems will be identified and addressed in a timely manner. In addition to our effective inspection program, we have a robust operating experience program that looks not only at US experience but also international experience to determine whether any issues warrant further NRC review or inspection.

Ho Nieh
Ho Nieh

What important advances have there been over the years concerning regulation and safety measurement? What improvements are being currently made in this area?

One recent noteworthy safety measure was the issuance of the Mitigation of Beyond-Design-Basis Events rule. The rule, based on lessons learned from the March 2011 nuclear accident at Japan’s Fukushima Daiichi plant, establishes requirements for cooling a reactor’s core and spent fuel pool and for preserving the containment following an event like what happened at Fukushima. Thanks to this rule all operating US nuclear power plants have additional safety systems that did not exist prior to the Fukushima nuclear accident. For example, every plant has on site portable cooling water pumps, electrical power supplies, and procedures to use them.

"The global nuclear safety community is active and, in my view, very focused on the safety and security of operating nuclear power plants and reactors under construction"

How do you see globally the word 'nuclear safety'? How is it possible to guarantee and monitor world nuclear safety?

The global nuclear safety community is active and, in my view, very focused on the safety and security of operating nuclear power plants and reactors under construction. This community includes the national nuclear safety regulatory bodies, technical support organizations and industry organizations such as the World Association of Nuclear Operators (WANO) and the US Institute of Nuclear Power Operations. For government bodies there are very effective multilateral fora, such as those hosted by the Nuclear Energy Agency (NEA) and the International Atomic Energy Agency (IAEA). International treaties and instruments, like the Convention on Nuclear Safety, and peer review activities sponsored by the IAEA also serve to strengthen national commitments to ensure nuclear safety. Having worked both at the IAEA and the NEA I have observed that the level of international cooperation for nuclear safety has grown steadily over the last two decades. In my view, this is a very positive sign and I believe that the level of cooperation will only continue to grow as the dynamic landscape of nuclear energy changes with the introduction of new technologies (like advanced reactors and new manufacturing techniques), new entrant countries and other emerging issues that will demand strong cooperation among nuclear safety regulators around the world.

Do you share information and good practices among the different regulatory organizations around the world as the Spanish regulatory body?

Absolutely! NRC and CSN have a very strong bilateral relationship. Sharing operating experience with CSN and other international regulators around the world helps us learn from each other. It’s important to learn about best practices as well as lessons learned.

"interest and advances in SMR are growing rapidly and demanding that regulators keep in step with modernization initiatives and the technologies of the future"

The US industry is embracing Small Modular Reactors. What advances regarding regulation is NRC making, and what do you think will be the contribution of SMRs in the future?

Globally, interest and advances in small modular and advanced reactors are growing rapidly and demanding that regulators keep in step with modernization initiatives and the technologies of the future. The NRC is taking measures to ensure the development and deployment of these innovative technologies are done safely and efficiently. We are also looking at new ways of working. For example, in August, the NRC signed a first-of-a-kind Memorandum of Cooperation with the Canadian Nuclear Safety Commission to increase regulatory effectiveness through collaborative work on the technical reviews of advanced reactor and small modular reactor technologies. We are also looking at how the existing regulatory framework for large light-water reactors can be adapted for the improved safety features of advanced reactors and small modular reactors. For example, the NRC is evaluating changes to siting, emergency preparedness, containment, and physical security requirements for advanced reactors and SMRs. The NRC is conducting periodic public meetings and is collaborating with external stakeholders, including international partners, to get insights and feedback to help inform these evaluations.

"The vast majority of plants in the U.S. already have authorization to operate to 60 years"

Long-term operation is a reality in the United States, where 90% of reactors hold authorizations to operate up to 60-year. What requirements did the applicants have to fulfill to get these authorizations? And to operate up to 80 years?

The requirements an applicant must meet to operate beyond 40 years are contained in the Code of Federal Regulations (10 CFR Part 54). The vast majority of plants in the U.S. already have authorization to operate to 60 years. When the NRC learned that the U.S. nuclear industry was interested in operating plants beyond that 60-year limit, we put on our thinking hats and began evaluating the regulatory framework to determine if changes were needed. We concluded that the regulatory framework used to evaluate license renewal applications was adequate to for subsequent license renewal (SLR) applications that would allow licensees to operate up to 80 years. Although license renewal regulations have not changed, the NRC updated its guidance documents by gathering lessons learned from the technical reviews conducted in the past. The revised guidance documents are allowing the NRC to conduct SLR reviews in a more efficient way and also focusing on key technical areas of interest in the period beyond 60-years of age. For these key technical areas, we are conducting extensive research and communicating with external stakeholders and international partners to share what we are learning. The NRC is currently conducting the review of three SLR applications (for a total of six units) and our research activities will continue to ensure that technological advances are considered in our regulatory evaluations, as appropriate.

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