Back to jobs
New

Senior Software Security Engineer

Torrance, California, United States

About Valar Atomics

At Valar Atomics, we're redefining what's possible in energy. Our mission is to make clean, high-temperature nuclear power scalable—unlocking abundant energy for industry, hydrogen, and next-generation manufacturing. We are a team of builders, engineers, and operators who believe nuclear energy should be fast to deploy, factory-made, and built for the real world. Our first pilot plant in Orangeville, Utah will demonstrate how advanced nuclear systems and fuel fabrication can power the future. Joining Valar Atomics means becoming part of a company where autonomy, ownership, and impact exist at every level.

The Team 

As part of the Business organization, IT & Enterprise Software delivers the technology infrastructure, enterprise applications, and digital tools that power Valar's operations. The team ensures secure, reliable, and scalable technology solutions that support every function across the company. 

The Role 

We're looking for a Software Security Engineer to embed security into our software development lifecycle — from initial design through shipped code. This role is split across two key moments: early-stage design and planning reviews, where you'll help engineering teams make secure architectural decisions before code is written, and post-development code review, where you'll dig into implemented code to find and fix vulnerabilities before release.

You'll work closely with engineering teams across our C#, Python, and React stack, along with our Postgres data layer, acting as a security partner rather than a late-stage gatekeeper. We strongly value candidates with backgrounds in large-scale technology organizations or the defense sector, where security rigor and compliance discipline are non-negotiable.

Key Responsibilities 

Design & Planning Reviews

  • Participate in design and architecture discussions early, before implementation begins
  • Perform lightweight threat modeling on new features and services — identifying trust boundaries, data flows, and likely attack surfaces
  • Flag risky design patterns (auth schemes, data handling, third-party integrations, database access patterns) and recommend secure alternatives
  • Provide security requirements and acceptance criteria that get built into planning/ticketing, not bolted on afterward

Code Review (Post-Development)

  • C#, Python, React: Perform manual and tool-assisted secure code review across all three
  • Postgres: Review queries and schema design for injection risks, access control issues, data exposure, and unsafe query patterns
  • React: Review front-end code for common web vulnerabilities (XSS, insecure state/data handling, unsafe use of dangerouslySetInnerHTML, client-side auth assumptions)
  • C#: Review backend code for issues like insecure deserialization, improper input validation, authorization flaws, and unsafe use of reflection/dynamic code
  • Provide clear, actionable remediation guidance directly to engineers — not just a list of flagged lines

Compliance & Ongoing

  • CMMC 2.0: Support alignment with Cybersecurity Maturity Model Certification (CMMC) 2.0 practices where applicable to contracts and data handling requirements
  • Maintain and refine secure coding guidelines specific to our stack (C#/.NET, Python, React, Postgres)
  • Track recurring vulnerability patterns across reviews and feed them back into design guidance and developer training
  • Partner with engineering leads to balance security rigor against delivery timelines

Basic Qualifications  

  • Professional experience in application security, software security engineering, or a related security-focused engineering role
  • Strong proficiency reading and reasoning about C# and Python code
  • Working knowledge of React and common front-end/web security issues
  • Experience reviewing Postgres (or other relational database) queries and schemas for security issues
  • Demonstrated experience doing security reviews at both the design/planning stage and the code-review stage — this is a dual-mode role, not just one or the other
  • Familiarity with OWASP Top 10, secure design principles, and basic threat modeling (e.g., STRIDE)
  • Strong written and verbal communication — you'll need to explain security tradeoffs to engineers and, sometimes, non-technical stakeholders

Preferred Skills and Experience  

  • Experience at a large-scale technology company ("big tech") or within the defense industrial base
  • Familiarity with CMMC 2.0 requirements and how they translate into engineering and software practices
  • Experience working under DFARS, NIST 800-171, or similar federal/defense compliance frameworks
  • Software/application security certifications: CSSLP (Certified Secure Software Lifecycle Professional), GWAPT (GIAC Web Application Penetration Tester), or GSSP (GIAC Secure Software Programmer)
  • General security certifications: CISSP, OSCP, or Security+

Nice to Have

  • Experience with SAST/DAST tooling and integrating security checks into CI/CD
  • Experience with SBOM / software supply chain security
  • Familiarity with cloud environments (AWS/Azure/)

What Success Looks Like

  • Security issues get caught in design discussions, before they're ever coded
  • Code review findings are specific, actionable, and rarely repeat the same root cause twice
  • Engineering teams bring you into planning conversations proactively, rather than security being an afterthought
  • The C#/Python/React/Postgres stack has clear, documented secure coding practices that teams actually follow
  • The organization maintains a clear path toward, or sustains, CMMC 2.0 compliance where required

What We Offer 

  • Competitive base salary 
  • Equity ownership in a rapidly growing advanced energy company 
  • Comprehensive medical benefits 
  • Unlimited PTO
  • Free daily lunch and dinner provided onsite 
  • Generous PPE stipend
  • High-impact startup environment with significant ownership and autonomy 
  • Opportunities for rapid career growth and internal advancement 
  • Direct collaboration with experienced operators, engineers, and industry leaders 
  • The opportunity to help build and scale transformative energy technology from the ground up

Equal Employment Opportunity Statement

Valar Atomics is an equal opportunity employer. We consider all qualified applicants without regard to race, color, religion, sex, gender identity, sexual orientation, national origin, age, disability, veteran status, or any other protected status under applicable law.

We are committed to providing a workplace free of discrimination and harassment and will provide reasonable accommodation as required by law.

Applicants must be legally authorized to work in the United States as a U.S. citizen or lawful permanent resident (green card holder).

Salary

$175,000 - $200,000 USD

Apply for this job

*

indicates a required field

Resume/CV*

Accepted file types: pdf, doc, docx, txt, rtf

Cover Letter

Accepted file types: pdf, doc, docx, txt, rtf

Select...
Select...

To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State.

Select...

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 Valar Atomics’s Equal Employment Opportunity policy, we do not discriminate on the basis of any protected group status under any applicable law.

Select...
Select...
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.

Select...

Voluntary Self-Identification of Disability

Form CC-305
Page 1 of 1
OMB Control Number 1250-0005
Expires 07/31/2029

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
Select...

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.