# How nuclear safety equipment proves it can survive a reactor accident

By MarketScale Newsroom · Published 2026-11-13 · Energy on MarketScale
Canonical: https://www.marketscale.com/industries/energy/how-nuclear-safety-equipment-proves-it-can-survive-a-reactor-accident-1306117

> Element engineers explain thermal and radiation aging, seismic shaking and LOCA testing, and why the report joins a reactor's licensed safety case.

## Key points

- Qualification runs in a fixed order, aging and irradiation before seismic shaking and the loss-of-coolant test, with a functional check after every stage.
- The IEEE standards tell a lab how to qualify equipment but set no stress levels; the plant's own specification decides how severe the test is.
- ASME QME-1-2025, published in November 2025, now names small modular and advanced reactors, and the NRC's Part 53 licensing rule was published as final in March 2026.

Derica Taylor's checklist for a safety-related actuator runs nine steps: pretest inspection, baseline functional test, thermal aging, radiation aging, cycle aging, pressure cycling, vibration aging, seismic simulation and finally a loss-of-coolant accident. The part may sit in a plant for forty years and never see the accident it was built for. It still has to prove, in a laboratory in Huntsville, Alabama, that it would work on the day it did.

Taylor, a nuclear equipment qualification engineer at Element Materials Technology, and Kyle McVay, PE, who manages the company's nuclear equipment qualification and commercial grade dedication (NEQ and CGD) department, walked through that sequence in a recent Element webinar, Testing the Accident Scenario, released as a MarketScale Studio segment and hosted by Michael Cool, Element's strategic marketing director for Aerospace, Space and Defense. Their subject was nuclear equipment qualification, or NEQ: the documented demonstration that a pump, valve, breaker or cable will perform its safety function under normal, abnormal and accident conditions for the life it is credited with.

The rules that shape that demonstration moved twice in the past year. ASME International published QME-1-2025, its standard for qualifying mechanical equipment in nuclear facilities, on November 7, 2025, and its scope statement now names small modular reactors and advanced reactors as well as conventional plants. On March 30, 2026 the U.S. Nuclear Regulatory Commission published its Part 53 final rule in the Federal Register, an alternative licensing framework the agency describes as technology inclusive, open to any reactor technology and any size. For the operator who buys qualified equipment, both changes land on the question Taylor and McVay spend an hour on: what counts as proof.

## Appendix B puts legal weight behind a test report

McVay began where every qualification program begins, with 10 CFR 50 Appendix B. The appendix sits inside Part 50 of Title 10 of the Code of Federal Regulations, the NRC's rules for the domestic licensing of production and utilization facilities, and the Electronic Code of Federal Regulations lists the Atomic Energy Act of 1954 as the statutory authority behind Part 50, with the NRC as the administering agency. McVay called it a governing directive, and explained what being in the federal code means in practice.

> That means it has teeth behind it. If you are a bad actor, you will get in trouble. You can be fined, and you can go to jail. — Kyle McVay, PE, Manager, Nuclear Equipment Qualification (NEQ and CGD), Element Materials Technology

That weight travels down to the lab. McVay described how a plant's design is summarized in a final safety analysis report, or FSAR, the top-level document that sits above the drawings, specifications and procedures the plant runs on. When the NRC accepts it, the plant is licensed, and it must then operate the way the FSAR and its quality assurance program say it will.

A qualification test report becomes a design basis document under the plant's license. When Element finishes a program, McVay said, the report is delivered as a design document; the utility compares the tested conditions with the installed location, decides the qualification envelops it, updates its own design documents and puts the equipment into service. From that point the report lives under the FSAR as part of what the plant offers the regulator to show how it complies.

McVay, who worked at Palo Verde Generating Station in Arizona as a nuclear fuels and dry cask storage engineer before joining Element in Huntsville in 2020, said that enforcement is why the plant side of the industry is so careful. For the procurement engineer at a utility, the consequence is that a qualification record may have to be defended to an inspector years after the vendor who produced it has moved on.

The reason one component carries so much weight is how plants are licensed. McVay described redundancy, multiple trains of the same equipment so a backup exists if one fails, and diversity, different systems and different equipment types that can reach the same safe shutdown function so a single design flaw cannot propagate through every train. Qualification is what lets a plant claim each of those trains will actually be available when the event arrives.

## The standards say how to test, and the plant says how hard

Taylor's working set of standards is short: IEEE 323, IEEE 344, IEEE 382 and, for mechanical equipment, ASME QME-1. Each gains its standing in a licensing case when the NRC endorses it, she said.

The layering matters. According to the IEEE Standards Association, IEEE 323 sets the basic requirements for qualifying Class 1E equipment, the electrical equipment essential to safety, and when its requirements are met they demonstrate and document the ability to perform a safety function under service conditions including design basis events, reducing the risk of common-cause failure. IEEE 382, per the same association, gives direction for applying 323's requirements to the specific features of safety-related actuators, which is why Taylor borrows its test list as a template for almost any component.

A design basis event, in McVay's telling, is one the plant is expected to withstand during its licensed life while staying online; an earthquake is the classic case. A beyond design basis event, which he also called a safe shutdown event, is one nobody expects to happen. If it does, the equipment's job narrows to getting the core cooled and keeping radiation away from the public.

IEEE 323 tells a lab how to qualify equipment; the plant's specification decides how hard the test hits. The IEEE page for the current international edition, IEC/IEEE 60780-323-2016, states that the standard does not provide environmental stress levels or performance requirements, and the companion seismic standard, IEC/IEEE 60980-344-2020, likewise does not specify seismic demand. That is why McVay said original equipment manufacturers, or OEMs, tend to qualify to the most restrictive conditions their product can still pass, so one program can be offered to many plants, while a utility ordering for a known location supplies its own limiting conditions up front.

## Forty years, compressed into a heated chamber

Thermal aging comes early in the sequence because, as Taylor put it, a component can sit at elevated temperature every day of its life and may be required to operate under normal conditions long before any accident. Heat changes material properties. The materials at risk are usually the non-metallic soft goods: O-rings, gaskets, cable jackets and coatings.

Qualified life is the span the equipment is credited for in the plant's records. McVay said plants are typically licensed for forty years, and Taylor used forty years as her working example.

The Arrhenius equation lets Element compress a forty-year qualified life into a calculated chamber duration. The equation is a chemistry relationship describing how the rate of a degradation reaction rises with temperature; run the reaction hotter and the same damage arrives sooner. Taylor's method has three steps: establish the service conditions (where the item goes, how long, at what temperature), determine the accelerated aging conditions, and hold the specimen at that higher temperature for the calculated time.

The calculation needs an activation energy for every non-metallic material in the device, a figure that sets how strongly that material's aging speeds up with heat. Each polymer in a device therefore needs its own value before the chamber setpoint can be fixed. For an OEM, that means knowing exactly which compounds are in every seal and jacket, down to the supplier's formulation, before a program is quoted.

Extending that life is written into the standard itself. According to the IEEE Standards Association, IEEE 323's methods cover qualifying equipment, maintaining and extending qualification, and updating it when the equipment is modified. The Canadian Nuclear Safety Commission's regulatory document RD-334 takes the same position from the regulator's side, requiring licensees to manage both physical aging and obsolescence of structures, systems and components through the plant's service life, including long-term operation, in a manner the commission says is consistent with International Atomic Energy Agency guidance.

For a utility planning to run past its original forty-year term, the question is whether the original aging data and activation energies still envelop the longer life or whether a fresh program is needed. The standards' answer is that qualification is extended or updated, never assumed. Taylor and McVay did not take up a specific life-extension case in the session.

## Radiation aging follows the primary loop

Radiation aging is the stage where the specimen absorbs the dose it would accumulate over its qualified life, and McVay's account of where that dose comes from explains which equipment needs it. During operation, he said, fission throws off neutrons and other radiation that activate atoms around the reactor coolant, nitrogen prominently. Those activation products have short half-lives, the time it takes for half of a radioactive material to decay, so they emit heavily while the plant runs and fade soon after shutdown.

Anything near the primary loop, the piping that carries coolant through the core and, in a pressurized water reactor, through the steam generator, therefore needs a high level of radiation qualification. Longer-lived activated corrosion products can collect in valves and pumps and keep emitting at a lower level even at shutdown, more so at boiling water reactors, where steam is raised directly in the reactor vessel. McVay said that exposure is monitored, with each utility tracking the dose its staff receives under the principle of keeping it as low as reasonably achievable.

Electronics are generally kept out of the harsh environment because, in McVay's words, radiation is very bad for them. Taylor said a functional check follows every stage, so the report carries results from before and after the radiation step as well as the thermal one. For an OEM, that split is what shows which stressor a change in performance followed.

## Shake it after it has aged, then flood it

Seismic simulation waits until aging is done because an earthquake should strike equipment that has already lived its life. McVay said nearly everything in a plant needs seismic qualification, since a seismic event affects every building whether or not the area is radiologically harsh.

According to the IEEE Standards Association, IEEE 344 provides procedures that yield data showing equipment can meet its performance requirements during and after one safe shutdown earthquake preceded by a number of operating basis earthquakes. An operating basis earthquake is the smaller shock the plant is designed to ride through while operating; the safe shutdown earthquake is the larger one it must survive while shutting down safely. The international edition, IEC/IEEE 60980-344-2020, states that the demonstration takes account of aging before the safe shutdown earthquake and considers aging phenomena that could make equipment more vulnerable to vibration, which is the engineering reason the shaker table comes after the chamber work.

The last stage is the accident itself. LOCA stands for loss-of-coolant accident, a break in the primary system that fills containment with hot, pressurized steam; HELB is a high energy line break, a rupture in a steam or feedwater line that produces a similar transient of temperature, pressure and humidity. McVay listed the harsh-environment stressors a specimen must face in combination: radiation, temperature, the LOCA or HELB transient, and humidity.

McVay acknowledged that programs do not always run clean, and that sometimes changes have to be made before everything passes. Neither Element nor the standards bodies publish a typical price or calendar for a full program; McVay described scope as built job by job at the quoting stage, with schedule treated as a priority. For an OEM, the useful planning fact is that the sequence is serial, so a stage that must be repeated pushes everything behind it.

He added a stage many buyers overlook. In the current fleet, he said, the ultimate safe shutdown path can mean pumping water from the sump of the reactor building back into the reactor vessel, so some equipment must also pass submergence qualification. He also cautioned that a mild environment is not a benign one: control and auxiliary buildings can see elevated temperature and humidity, and electrical equipment there is checked for electromagnetic compatibility, since a handheld radio passing by can trigger interference.

McVay said Element is reviewing operating experience on electromagnetic events collected by the NRC and the Electric Power Research Institute, or EPRI, this year, with a presentation planned for next year. For a plant engineer specifying instrumentation for an auxiliary building, that review is the next piece of published guidance to watch.

## Small reactors stretch a light water playbook

Taylor called the standards mature, with few changes. The publication record tells a busier story. According to the IEEE Standards Association, IEEE 323-2003 was superseded by IEC/IEEE 60780-323-2016, a joint international edition whose scope adds certain design extension conditions beyond design basis events; IEEE 344-2013 was superseded by IEC/IEEE 60980-344-2020; and IEEE 382-2006 gave way to 382-2019, which now implements the international 323 and extends to nuclear facilities beyond power stations.

ASME's mechanical standard has moved as fast. The document history on the Accuris store listing for ASME QME-1-2025 shows editions dated 2012, 2017, 2023 and 2025, with the title widening from active mechanical equipment in nuclear power plants to mechanical equipment in nuclear facilities, and the current scope describing pumps, valves and dynamic restraints in power plants, small modular reactors and advanced reactors. Taylor's point still holds for the requirements a light water plant must meet; the editions change mostly in who else they cover.

McVay said he was not familiar with how licensing for the new technologies is being handled, only that the NRC has been developing new guidance. That guidance is now a rule. The NRC describes Part 53 as a risk-informed, performance-based alternative to the existing framework, which the agency says evolved mainly around the light water reactors in the current fleet, and the agency says it lets applicants propose design features to meet safety objectives rather than follow prescribed methods, relying on probabilistic risk assessment and other systematic risk evaluations.

For a lab, the open question under Part 53 is who sets the service conditions a specimen must survive when the design uses molten salt or an unconventional pressure boundary, both of which McVay mentioned as live SMR concepts with their own pros and cons. IEEE 323 already sends the lab to the plant's specification for stress levels, and a risk-informed license puts more of that specification in the applicant's own analysis.

The direction of travel is not uniform. NPR reported in January 2026 that the Department of Energy had revised the departmental orders governing a program of experimental commercial reactors it oversees, with the stated aim of accelerating a new generation of designs, and that the revisions reduced recordkeeping requirements among other changes. Those orders apply to DOE-authorized facilities, a separate track from NRC-licensed commercial plants where Appendix B governs, and McVay's account of enforcement applies to the NRC side.

The signal Taylor points to is endorsement: a standard carries weight in a licensing case once the NRC endorses it. For a supplier aiming at small modular reactors, the milestone to watch is the agency's treatment of QME-1-2025 and the joint IEC/IEEE qualification editions under Part 53. Until then, the sequence Taylor laid out stands: age it, irradiate it, shake it, flood it, and keep every functional result in a report the plant can defend forty years on.

## Sources

- [Appendix B to Part 50, Title 10](https://www.ecfr.gov/current/title-10/chapter-I/part-50/subject-group-ECFR89aa6ca4aada73c/appendix-Appendix%20B%20to%20Part%2050) (eCFR / Nuclear Regulatory Commission)
- [IEEE 323-2003, Standard for Qualifying Class 1E Equipment for Nuclear Power Generating Stations](https://standards.ieee.org/ieee/323/523/) (IEEE Standards Association)
- [IEEE 344-2013, Standard for Seismic Qualification of Equipment for Nuclear Power Generating Stations](https://standards.ieee.org/ieee/344/5599/) (IEEE Standards Association)
- [IEEE 382-2006, Standard for Qualification of Safety-Related Actuators for Nuclear Power Generating Stations](https://standards.ieee.org/ieee/382/4015/) (IEEE Standards Association)
- [ASME QME-1-2025, Qualification of Mechanical Equipment Used in Nuclear Facilities](https://store.accuristech.com/standards/asme-qme-1-2025?product_id=3039498&srsltid=AYCX9vIrKHT5KkNyedRLda0QEgY8FofY25rk-fPHa-5ApQBojOmVdZNB) (ASME International)

Tags: Element Materials Technology, nuclear equipment qualification, IEEE 323, LOCA testing, energy and utilities, engineering and procurement

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