The Science of Filtration July 25, 2025, 9:56 pm

BACK

The Science of Filtration July 25, 2025, 9:56 pm

July 26, 2025

Check out our most recent video

How to Evacuate an AC system, Full Vacuum Procedure

Our latest Podcast

HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

In this fascinating episode, Bryan welcomes back longtime friend and nuclear industry veteran Bill Nowicki to discuss a recently released document from DHS and NUSTL that provides new recommendations for HVAC operations during nuclear events. Bill brings over 40 years of nuclear experience, starting as a 19-year-old Navy nuclear operator (after being deemed “not ready for the grill” at Friendly’s restaurant) and progressing through various roles, including lead engineer on critical control systems at nuclear facilities. Bill shares his journey from nuclear plant evaluator to leadership trainer, now working internationally to help nuclear professionals develop their skills. His current podcast, “The Nuclear Leader,” continues this mission alongside his passion project, “Navigating Mental Illness: Parent Stories.”

Bill provides an accessible explanation of nuclear reactor operations, using the analogy that “contamination is the poop and radiation is the smell” to help listeners understand the difference between radioactive material and radiation itself. He walks through the three-barrier system in nuclear plants: fuel cladding, reactor coolant system, and containment structures. The discussion covers how fission works, the controlled chain reaction process, and what happens when these systems fail, using examples from Three Mile Island, Chernobyl, and Fukushima to illustrate different failure modes.

The episode explores the current nuclear renaissance driven by AI data centers and industrial companies seeking clean baseload power. Bill explains how private industry is now directly funding nuclear projects, bypassing traditional utility structures, with companies like Microsoft and ExxonMobil investing billions in new nuclear facilities. This represents a dramatic shift from the post-Three Mile Island era when nuclear construction essentially stopped in the United States.

The core discussion focuses on updated emergency guidance that reverses previous recommendations. Instead of the old “shelter in place and shut off your AC” advice, the new guidance suggests keeping HVAC systems running while eliminating outdoor air intake. This approach recognizes that modern, well-sealed buildings with high-efficiency filtration can provide better protection by maintaining positive pressure and filtering recirculated air rather than allowing uncontrolled infiltration.

Bill and Bryan discuss how building characteristics dramatically affect the best response strategy. High-performance homes with tight construction, MERV 13+ filters, and controlled ventilation systems offer significant advantages, requiring only the ability to shut off outdoor air intake. Conversely, older, leaky buildings may still benefit from complete system shutdown to prevent contamination circulation. The conversation highlights how lessons learned during COVID-19 about airborne contamination and filtration directly apply to nuclear emergency preparedness, emphasizing the importance of case-by-case analysis rather than one-size-fits-all approaches.

Topics Covered

Nuclear industry career paths – From Navy nuclear training to civilian plant operations and leadership roles
Basic nuclear physics – Fission process, chain reactions, and the difference between contamination and radiation
Nuclear plant safety systems – Three-barrier containment approach and historical accident analysis
Current nuclear renaissance – AI-driven power demand and private industry investment in new reactors
Emergency preparedness evolution – How COVID-19 research influenced nuclear emergency HVAC guidance
Building performance factors – Impact of construction quality, filtration, and ventilation design on safety
HVAC system modifications – Importance of outdoor air shutoff capability and high-efficiency filtration
Case-by-case response strategies – Why building characteristics determine optimal emergency procedures
Podcasting journey – Early days of niche podcasting and building communities around specialized topics
Leadership development – International nuclear industry training and professional development
Personal stories – Navy submarine experiences and nuclear plant operational challenges

Here is the full document from the DHS: https://www.nrc.gov/docs/ML2425/ML24250A059.pdf

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Subscribe to our podcast on your iPhone or Android.

Subscribe to our YouTube channel.

Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

Search Episodes

What to Do in a Nuke Disaster – W/ Bill Nowicki

08/28/2025

Bryan Orr

Making Stuff Real – Short #254

08/26/2025