Last updated: October 2026
The Naval Nuclear Laboratory (NNL) is one of the few employers where a fall applicant is late, not early. Every hire needs a Department of Energy security clearance, which NNL's FAQ says "typically takes about six months", so it tells students to apply by the end of the calendar year before the internship. In plain words: you apply by 31 December 2026, you intern in summer 2027. Six summer 2027 internship reqs were open on NNL's job board on 3 October 2026, each listing $25.00 to $42.50 an hour, and all candidates must be U.S. citizens. Miss the date and your next chance is summer 2028, with applications expected around February to March 2027.
Quick Facts
| Fact | Detail |
|---|---|
| Where to apply | NNL job board (search "Internship Summer 2027"); program overview on the Internships and Co-ops page. Check the board weekly, since reqs are added mid-cycle. |
| Application window (2027–28) | Summer 2027: open now, window announced ~Feb–Mar 2026; apply by 31 Dec 2026 (NNL FAQ). Summer 2028: expected to open ~Feb–Mar 2027 and close ~31 Dec 2027 |
| Rolling? | Hard deadline: apply by the end of the previous calendar year. Community reports suggest many selections happen in the fall |
| Eligibility | U.S. citizens only; at least one full year of college completed by May 2027; enrolled throughout; transcript and resume required; 3.0 GPA preferred |
| Duration | 10–12 weeks, starting May/June 2027 |
| Compensation | $25.00–$42.50/hr (all six reqs), plus a stipend if school and home are more than 50 miles from the site; 9/80 schedule option |
| Return offers | "May result in a return internship or full-time employment offer"; no rate published |
| Locations | West Mifflin, PA (Bettis, 5 reqs) and Niskayuna, NY (Knolls, 1 req) this cycle; NNL also has sites in West Milton NY, Idaho and Charleston SC |
| # Programs | Summer internships (6 disciplines live) plus a 30-week co-op starting in January; no co-op req is posted today |
Summer 2027 applications are open now, and NNL's own rule puts the practical deadline at 31 December 2026.
Externships are short, remote programs where you finish a real project for a real company, most commonly over 8 weeks at 5 to 10 hours a week. The Hydroficient IoT Cyber Defense Externship fits NNL's IT systems and computer engineering roles, and the Breaking Games SQL Database Architecture Externship gives data science and IT applicants hands-on database work. Explore all Externships.
What Is a Naval Nuclear Laboratory Internship?
A Naval Nuclear Laboratory internship is a paid 10 to 12 week summer technical placement at the lab that designs and supports the reactors powering U.S. Navy submarines and aircraft carriers. NNL is a civilian organization operated for the Department of Energy by Fluor Marine Propulsion, a Fluor subsidiary, with "nearly 8,000" employees across Pennsylvania, New York, South Carolina and Idaho, per its About Us page. Interns work with engineers and scientists on modeling, data analysis, software and component testing. The program ends with a presentation to management and includes a meeting with the general manager, site tours and a trip to a Naval Shipyard.
When Do Naval Nuclear Laboratory Internship Applications Open for 2027–2028?
NNL's summer 2027 window opened long before its board dates suggest. NNL announced its co-op and internship window on 23 February 2026 and linked a summer 2027 posting by 2 March 2026; today's six reqs carry September dates because they were reposted or added. That's a lead time of about 15 months to a June 2027 start. A 2024 commenter says the window "tends to reopen in February/March of every year", so summer 2028 is expected then, with moderate confidence.
Applications for summer 2027 are open right now: Chemistry and Chemical Engineering, Computer Engineering, Data Science, Electrical Engineering, IT Systems Administration and Materials Engineering. Apply now; you're in the last quarter of a window that opened in early 2026.
Fall career fairs and interviews. NNL's FAQ says to bring a resume to the fair and also apply online. One commenter says the previous summer's interns were likely hired in October, so earlier is safer.
Apply-by date for summer 2027, from NNL's FAQ rule: "participants must apply by the end of the previous calendar year" to allow time for DOE clearance processing.
Expected: applications for summer 2028 open. Summer 2027 hires spend these months in clearance processing, which NNL says averages about three months and typically takes around six.
Internships start in May or June 2027 and run 10 to 12 weeks, ending with a presentation to management. Strong interns may get a return internship or full-time offer.
How to read this page: our dates come from tracking previous recruiting cycles and daily posting data. Treat them as informed estimates based on historical patterns, not confirmed dates. The company's official careers page is always the most current source. If a role is posted there, go by that, even if this page suggests the window hasn't opened yet.
Why You Must Apply the Week Applications Open
NNL's deadline is set by the clearance clock, not by how fast seats fill. A DOE clearance typically takes about six months, so the lab needs your application by 31 December 2026 to have you cleared for a May or June start. The reqs themselves show no closing date, which is exactly why students miss it. There's also a softer cutoff: a commenter on r/NuclearPower says the summer 2026 interns were likely hired in October. Apply this month, with your transcript and resume attached.
Which Naval Nuclear Laboratory Internship Programs Should You Target?
NNL hires interns by discipline, and every summer 2027 req uses the same program template. These six were live on 3 October 2026.
| Program | Focus | Duration | Key skills |
|---|---|---|---|
| Electrical Engineering (West Mifflin, PA) | Designing and testing components and integrated systems | 10–12 weeks | EE or computer engineering coursework |
| Computer Engineering (West Mifflin, PA) | Software and hardware for reactor systems | 10–12 weeks | Software, EE, nuclear or mechanical engineering; Git preferred |
| Data Science (Niskayuna, NY) | Models and data analysis | 10–12 weeks | Data science or computer science |
| IT Systems Administrator (West Mifflin, PA) | Secure IT systems support | 10–12 weeks | Information technology or information science |
| Chemistry & Chemical Engineering (West Mifflin, PA) | Chemistry support for naval reactors | 10–12 weeks | Chemistry or chemical engineering |
| Materials Engineering (West Mifflin, PA) | Materials and welding engineering | 10–12 weeks | Materials or welding engineering; welding process knowledge preferred |
Read each req on the NNL job board. A Nuclear Engineering summer 2027 req listed on aggregators is no longer on NNL's board.
What Are the Eligibility Requirements?
NNL's rules come from the security clearance, so most are strict.
• Citizenship: "All candidates must be U.S. citizens." Dual citizens must be willing to renounce the other citizenship and stop using a foreign passport, per NNL's FAQ.
• Class year: you must have completed at least your first full year of college by May 2027 and stay enrolled throughout the internship.
• Documents: attach your latest unofficial transcript and a resume with your graduation date; NNL says it won't accept an application missing either one.
• GPA: a cumulative 3.0 is listed as preferred, not required.
• Screening: a federal background investigation, DOE clearance eligibility and a drug test that covers marijuana.
Is the 3.0 GPA a Hard Cutoff?
No. All six reqs put "Cumulative minimum GPA 3.0/4.0" under preferred skills, next to prior internship experience and DOE or Navy program experience. The hard gates sit elsewhere: U.S. citizenship, a complete application with transcript, and clearance eligibility. A student at 2.8 with a relevant project or a lab job is still worth a shot.
What Skills Does the Naval Nuclear Laboratory Look For, and How Do You Build Them?
NNL's summer 2027 reqs share one template, so they say more about who can apply than about software tools. The work is described as "researching and developing new technologies and concepts; designing and testing software, components or integrated systems; developing models and performing data analysis". Two reqs add specific skills: Git experience for Computer Engineering and welding process knowledge for Materials Engineering. Your degree field and coursework do most of the work here.
What Naval Nuclear Laboratory looks for in interns
Skills across 6 Naval Nuclear Laboratory intern & analyst job descriptions · live summer 2027 reqs, October 2026
Method: full-text reading of the six NNL summer 2027 internship requisitions live on its job board on 3 October 2026. All six use one shared template, so the top six rows appear in every req by design.
How Is Demand for Engineering Interns Moving Right Now?
Mechanical engineering intern postings · Sep vs Aug 2026
vs 207 in August
Most engineering employers opened in September, but NNL opened months earlier and closes by its December rule. Apply to NNL first, then use the fall wave elsewhere as backup.
Daily US job-posting counts, Sep 1–30 vs Aug 1–31, 2026. Covers under half of US postings; shows direction, not market size. Pay = median of employer-published ranges only (87 postings in September, 36 in August).
Build These Skills Before You Apply
These rows map NNL's req language to remote Externships that give you a finished project to discuss.
| Skill (from real JDs) | JD evidence | Externship that builds it |
|---|---|---|
| Secure IT systems | IT Systems Administrator Internship: information technology and information science | Hydroficient IoT Cyber Defense |
| Databases and data handling | Data Science Internship: "developing models and performing data analysis" | Breaking Games SQL Database Architecture |
| Applied AI and automation | Data Science and Computer Engineering: software design and data analysis | Wayfair n8n AI Agent Engineering |
| Process controls and procedures | Shared template: "supporting operations and developing process controls and procedures" | Amazon Fulfillment Center Operational Strategy & People Analytics |
None of these Externships is affiliated with NNL. They're useful because NNL's preferred skills include prior related work, paid or volunteer, and a finished project counts toward that.
What Is the Naval Nuclear Laboratory Application and Interview Process Like?
NNL publishes its general hiring process; the intern-specific detail comes from community reports.
1. Apply online by discipline. Attach your unofficial transcript and resume with your graduation date, or the application is rejected.
2. Meet NNL at a fall career fair. The FAQ says to bring a resume and also submit online.
3. Interview. Interns on r/AskEngineers describe a single 30-minute phone interview. NNL's general hiring page describes longer on-site interviews and an answer in three to four weeks, but that isn't intern-specific.
4. Offer and clearance paperwork. You complete the federal background forms; bring two forms of unexpired ID to any on-site step.
5. DOE clearance. About three months on average and typically up to six, per NNL. There are no interim clearances.
One community tip worth taking: read up on the Rickover principles and prepare a story about a time your integrity was tested.
What Students on Reddit Say
Students on Reddit mostly talk about timing and the clearance-driven pace.
A student who applied in spring was told this is a clearance job: the summer 2026 interns were likely hired the previous October, so a spring applicant is really in the pool for the following summer. Another commenter suggested studying the Rickover principles and preparing an integrity example.
Several applicants described the same intern interview: one 30-minute phone call, then a wait. Some heard nothing for weeks, while one reported an offer arriving later in the cycle.
A commenter who described NNL as intimidating at first said interns learn a lot and get a head start on their careers, and that the odds of a job offer are high because the lab is always hiring.
How Do You Stand Out for a Naval Nuclear Laboratory Internship?
First, apply early and completely. NNL screens out applications without a transcript, and the clearance clock rewards fall applicants, so a complete application in October beats a polished one in December. Second, show you can follow procedure: community advice is to read the Rickover principles and have a concrete story about doing the right thing at a cost. Third, tie your coursework to the req's work, whether that's modeling, data analysis, component testing or process controls. NNL doesn't publish applicant numbers or a conversion rate.
What Other Companies Should You Consider?
These employers hire the same nuclear and defense engineering students.
- FluorNNL's operator parent through Fluor Marine Propulsion; separate corporate internshipsGuide →
- Huntington Ingalls Industriesbuilds nuclear carriers and submarines at Newport NewsGuide →
- General DynamicsElectric Boat builds the Navy's nuclear submarinesGuide →
- Idaho National LaboratoryDOE nuclear lab next to NNL's Idaho siteGuide →
- BWX Technologiesmakes naval reactor components; the closest supplier peerCareers site
For more defense and space options, see our aerospace and defense internships summer 2027 guide.
FAQ
Can I still apply for a summer 2026 Naval Nuclear Laboratory internship?
No. Summer 2026 internships have ended, and NNL's rule meant applications for them were due by 31 December 2025. The next open door is summer 2027: six reqs are live now, and NNL asks you to apply by 31 December 2026 so your DOE clearance can finish in time.
When is the Naval Nuclear Laboratory internship deadline for summer 2027?
Apply by 31 December 2026. NNL's FAQ says participants must apply by the end of the previous calendar year to allow time for DOE security clearance processing. The reqs themselves show no closing date, and community reports suggest many selections happen in the fall, so October or November is safer.
When do applications for summer 2028 open?
Expect around February to March 2027. NNL announced its last window on 23 February 2026 and linked a summer 2027 posting by 2 March 2026, and a 2024 commenter said the window tends to reopen each February or March. Confidence is moderate, so check the board from January 2027.
How much do Naval Nuclear Laboratory interns make?
Each summer 2027 req lists $25.00 to $42.50 an hour, based on experience and qualifications. Interns whose school and home addresses are both more than 50 miles from the work site can get a stipend. NNL also lists a 9/80 schedule option and 401(k) eligibility for interns.
Do I need to be a U.S. citizen?
Yes. Every req says "All candidates must be U.S. citizens", because each employee needs a DOE security clearance. Dual citizens must be willing to renounce their other citizenship and stop using a non-U.S. passport. Green-card holders and international students aren't eligible for NNL internships.
How long does the NNL security clearance take?
NNL gives two official figures. Its FAQ says a DOE clearance typically takes about six months, and its hiring-process page says two months to a year, averaging three months. DOE doesn't allow interim clearances, which is why NNL sets its December apply-by rule for the following summer.
Is the Naval Nuclear Laboratory part of the Navy?
No. NNL is a civilian organization operated for the Department of Energy by Fluor Marine Propulsion, a Fluor subsidiary. It designs and supports the Navy's nuclear propulsion plants and trains the sailors who run them, but interns are civilian employees, not service members.
Where are NNL internships located?
This cycle's six reqs are in West Mifflin, Pennsylvania, at the Bettis Atomic Power Laboratory (five roles) and Niskayuna, New York, at the Knolls Atomic Power Laboratory (one role). NNL also runs sites in West Milton, New York, Idaho and Charleston, South Carolina, which may post roles in other cycles.
NNL's summer 2027 reqs are open and its apply-by date is 31 December 2026. Send a complete application this month, then use a remote Externship to build a project you can talk about while your clearance paperwork moves.
About the Author
Bifei Wang has spent 17 years focused on human flow and the growth of young professionals, spanning international education, career training and coaching, and recruitment process outsourcing. Over 7 years at Extern, he has had one-on-one sessions with thousands of students exploring careers in consulting, finance, tech, marketing, and data, giving him a firsthand view of how the job market has shifted for early-career professionals and what it actually takes to break in.
