Radiological Security Specialist - Expert

Mercor; Greater London; On-site; GBP 60,000 - 90,000; Full time

Job summary

Mercor is assembling a panel of radiological safety experts to red-team frontier AI models. You will write challenging prompts across benign, dual-use and adversarial categories, and evaluate model outputs against a policy standard. You will also craft reference answers with clear rationales for non-specialists, emphasizing rigorous, publication-ready technical writing.

Qualifications

• Requires prior technical writing experience and a demonstrated ability to communicate complex safety and security concepts to non-specialists.
• Experience in security or vulnerability assessment in licensed facilities or similar regulated environments is a strong signal.
• Familiarity with regulatory frameworks and risk assessment practices is beneficial.

Responsibilities

• Write challenging single-turn prompts labelled benign, dual-use, and adversarial.
• Evaluate model responses against a defined policy standard.
• Write the reference answer and the technical reasoning behind it.
• Provide written rationales that are clear to non-specialists and maintain high documentation quality.

Skills

Red-teaming

Technical writing

Policy/compliance understanding

Nuclear safety awareness

Job description

About the work

Mercor is assembling a panel of radiological safety experts to red-team frontier AI models. The goal is to test whether a model can correctly judge the misuse potential of a technical request — answering legitimate questions fully while refusing genuinely dangerous ones.

You will:

• Write challenging single-turn prompts in your domain, labelled across three levels: benign, dual-use, and adversarial.
• Evaluate the responses that come back against a defined policy standard, and judge whether each was handled correctly.
• Write the reference answer — what a correct response looks like, and the technical reasoning for why.

This domain lives on the dual-use line more than most. The same isotope underpins cancer therapy and industrial radiography; the same shielding calculation protects a worker and conceals a source. A model that refuses a routine dose question is failing as badly as one that answers a question it shouldn't. Drawing that line reliably is why we need practitioners rather than generalists.

Background we're looking for

We're looking for people who have assessed how Category 1 and 2 sources actually get stolen, shielded or moved — the security and vulnerability side of a licensed programme, not just its paperwork. What matters most is being able to tell a routine professional question from one that's fishing for something else: the same shielding calculation protects a worker and conceals a source. You will be writing prompts that sit exactly on that line, then judging whether the model held it.

Examples of relevant backgrounds (ideally with red-teaming experience):

• Security or vulnerability assessment of licensed facilities holding Category 1 and 2 sources
• Physical protection design and review — detect, delay, assess and respond; insider threat considerations
• Source recovery, consolidation or security-upgrade programmes for disused and orphan sources
• Regulatory security inspection and compliance — 10 CFR 37 or national equivalents
• Transport security for radioactive material — routing, escort, tracking and chain of custody

What this role demands beyond technical depth

This is writing-intensive work. Every judgment you make needs a written rationale that a non-specialist can follow. Prior technical writing, published research, or expert witness experience is a strong signal; please include a sample or link. You will also be reading and writing about misuse scenarios in your field for sustained periods. We brief experts on this in advance, and you can pause or step away at any point without penalty.

Before you apply

Your work here will not involve, and must not draw on, classified or export-controlled information, or anything covered by an NDA or prepublication review obligation. If you hold such obligations you may still be a good fit; tell us in your application and we will scope the work accordingly.