Radiant Industries is an El Segundo, CA-based startup developing Kaleidos, a portable, containerized nuclear microreactor. Portable nuclear power with rapid deploy capability can replace diesel generators used today to provide critical asset support for hospitals, datacenters, and military bases or to power microgrids at remote sites. Radiant’s unique, practical approach to nuclear development utilizes modern software engineering to rapidly achieve safe, factory-constructable microreactors leveraging existing, well-qualified materials. Radiant is on a fast track to demonstrate the first fueled operation of a new commercial nuclear reactor design, just two years from now. 

Senior Radiation Shielding Engineer 

Radiant is seeking a talented nuclear radiation shielding engineer to design, analyze, and develop shielding solutions for the 1 MW Kaleidos nuclear microreactor. You will design, test, and iterate on complex shielding designs optimized for a portable system. This role requires creative problem solving, first principles understanding, and an interdisciplinary mindset. The ideal candidate has the drive and tenacity to solve interesting technical challenges and are excited to commercialize a nuclear microreactor to power remote areas and microgrids anywhere.  

Responsibilities:  

  • Own and drive design and analysis of radiation shielding, including assessing reactor pressure vessel and system component activation, fuel handling requirements, and transportation/storage requirements.  
  • Perform trade studies of optimal approaches balancing safety, size, mass, cost, and performance. 
  • Perform complex dose calculations with MCNP, OpenMC, and/or SCALE, and use these findings to inform on design decisions.   
  • Assess radiological conditions during transport, operation, including self-activation, environmental activation, and waste categorization.  
  • Provide expertise and feedback via clear and constructive communication cross-functionally.  
  • Develop and see through technical requirements for hardware systems, structures, and components, and lead design reviews.  
  • Own shielding schedule, including design, manufacturing, and testing. 
  • Find and develop suppliers for all components.  
  • Own regulatory and quality compliance as related to shielding.  

Required Qualifications and Skills: 

  • Bachelor’s degree in nuclear engineering or equivalent degree from accredited institution. 
  • 5+ years nuclear engineering industry experience. 
  • Experience in academia and/or industry in shielding.  
  • Proficient in MCNP, OpenMC, or SCALE. 

Desired Qualifications and Skills: 

  • Master’s or PhD in nuclear engineering or equivalent degree from accredited institution. 
  • Hands on experience designing or owning hardware and/or performing tests.  
  • Self-motivated to solve complex technical problems in a collaborative, fast-paced startup environment.  
  • Software development experience in C, C++, or Python.  
  • Proficient with general nuclear tools such as: MOOSE, Serpent, Attila, BISON, RELAP, CFD, or other nuclear software packages.  

Employee Benefits for Eligible Employees:

  • Stock: Substantial incentive stock plan for all full time, salaried employees.
  • Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
  • One Medical: Sponsored memberships for employees and their dependents. 
  • Vision: 100% top tier plan coverage + 50% for dependents.
  • Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
  • Voluntary Life, Accident, Hospital, Critical Illness, Commuter and FSA are offered as employee contributed benefits.
  • Free snacks and drinks onsite. 
  • Flexible PTO policy.

We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.

Unfortunately, we are unable to provide visa sponsorship at this time. This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.

Apply for this Job

* Required
resume chosen  
(File types: pdf, doc, docx, txt, rtf)
cover_letter chosen  
(File types: pdf, doc, docx, txt, rtf)


Voluntary Self-Identification

For government reporting purposes, we ask candidates to respond to the below self-identification survey. Completion of the form is entirely voluntary. Whatever your decision, it will not be considered in the hiring process or thereafter. Any information that you do provide will be recorded and maintained in a confidential file.

As set forth in Radiant ’s Equal Employment Opportunity policy, we do not discriminate on the basis of any protected group status under any applicable law.

Race & Ethnicity Definitions

If you believe you belong to any of the categories of protected veterans listed below, please indicate by making the appropriate selection. As a government contractor subject to the Vietnam Era Veterans Readjustment Assistance Act (VEVRAA), we request this information in order to measure the effectiveness of the outreach and positive recruitment efforts we undertake pursuant to VEVRAA. Classification of protected categories is as follows:

A "disabled veteran" is one of the following: a veteran of the U.S. military, ground, naval or air service who is entitled to compensation (or who but for the receipt of military retired pay would be entitled to compensation) under laws administered by the Secretary of Veterans Affairs; or a person who was discharged or released from active duty because of a service-connected disability.

A "recently separated veteran" means any veteran during the three-year period beginning on the date of such veteran's discharge or release from active duty in the U.S. military, ground, naval, or air service.

An "active duty wartime or campaign badge veteran" means a veteran who served on active duty in the U.S. military, ground, naval or air service during a war, or in a campaign or expedition for which a campaign badge has been authorized under the laws administered by the Department of Defense.

An "Armed forces service medal veteran" means a veteran who, while serving on active duty in the U.S. military, ground, naval or air service, participated in a United States military operation for which an Armed Forces service medal was awarded pursuant to Executive Order 12985.


Voluntary Self-Identification of Disability

Form CC-305
Page 1 of 1
OMB Control Number 1250-0005
Expires 04/30/2026

Why are you being asked to complete this form?

We are a federal contractor or subcontractor. The law requires us to provide equal employment opportunity to qualified people with disabilities. We have a goal of having at least 7% of our workers as people with disabilities. The law says we must measure our progress towards this goal. To do this, we must ask applicants and employees if they have a disability or have ever had one. People can become disabled, so we need to ask this question at least every five years.

Completing this form is voluntary, and we hope that you will choose to do so. Your answer is confidential. No one who makes hiring decisions will see it. Your decision to complete the form and your answer will not harm you in any way. If you want to learn more about the law or this form, visit the U.S. Department of Labor’s Office of Federal Contract Compliance Programs (OFCCP) website at www.dol.gov/ofccp.

How do you know if you have a disability?

A disability is a condition that substantially limits one or more of your “major life activities.” If you have or have ever had such a condition, you are a person with a disability. Disabilities include, but are not limited to:

  • Alcohol or other substance use disorder (not currently using drugs illegally)
  • Autoimmune disorder, for example, lupus, fibromyalgia, rheumatoid arthritis, HIV/AIDS
  • Blind or low vision
  • Cancer (past or present)
  • Cardiovascular or heart disease
  • Celiac disease
  • Cerebral palsy
  • Deaf or serious difficulty hearing
  • Diabetes
  • Disfigurement, for example, disfigurement caused by burns, wounds, accidents, or congenital disorders
  • Epilepsy or other seizure disorder
  • Gastrointestinal disorders, for example, Crohn's Disease, irritable bowel syndrome
  • Intellectual or developmental disability
  • Mental health conditions, for example, depression, bipolar disorder, anxiety disorder, schizophrenia, PTSD
  • Missing limbs or partially missing limbs
  • Mobility impairment, benefiting from the use of a wheelchair, scooter, walker, leg brace(s) and/or other supports
  • Nervous system condition, for example, migraine headaches, Parkinson’s disease, multiple sclerosis (MS)
  • Neurodivergence, for example, attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder, dyslexia, dyspraxia, other learning disabilities
  • Partial or complete paralysis (any cause)
  • Pulmonary or respiratory conditions, for example, tuberculosis, asthma, emphysema
  • Short stature (dwarfism)
  • Traumatic brain injury

PUBLIC BURDEN STATEMENT: According to the Paperwork Reduction Act of 1995 no persons are required to respond to a collection of information unless such collection displays a valid OMB control number. This survey should take about 5 minutes to complete.


Our system has flagged this application as potentially being associated with bot traffic. Please turn off any VPNs, clear your browser cache and cookies, or try submitting your application in a different browser. If this issue persists, please reach out to our support team via our help center.
Please complete the reCAPTCHA above.