Oklo
Core Thermal-Hydraulics Methods Engineer
Santa Clara, CA or remote Thanks for your interest in Oklo! We are searching for a Core Thermal-Hydraulics Methods Engineer to join our team. Position Description Thermal-Hydraulics Engineers at Oklo are responsible for analyzing fluid flow and heat transfer within a reactor and associated systems. This work includes engineering analyses of thermal-fluid dynamics, clear and thorough documentation of the analyses, as well as interfacing with design teams. A Core Thermal-Hydraulics Methods Engineer will contribute to the development, qualification, and validation of methods for modeling coolant flow within reactor cores using one-dimensional models and intermediate-fidelity subchannel models. Specific responsibilities may include: Modeling core thermal-hydraulic behavior using subchannel codes such as DASSH, or MOOSE-Subchannel one-dimensional systems codes such as SAS4A/SASSYS-1 or SAM first principles approaches and in-house flow network models Developing methods to analyze core thermal-hydraulic behavior at steady-state and during transients Developing and utilizing analysis methods that efficiently and effectively build confidence in a design Automation, verification, and validation of modeling and simulation tools in support of analyses Collaborating cross-functionally to define design requirements, and providing technical feedback to quick-iterating design teams Document work using modern tools and techniques, and write well-written, thoughtful technical reports Minimum Qualifications Bachelors, Masters, or PhD in a technical field, such as nuclear, mechanical, or aerospace engineering Proficiency with thermal-hydraulics (thermal fluids) analysis methods Core competencies in heat transfer, fluid dynamics, and thermodynamics first principles Experience with low-fidelity and intermediate-fidelity (e.g., porous body and correlation-based) models for heat transfer and fluid flow Experience with numerical methods and software development for heat transfer and fluid flow problems Experience with data processing (e.g., pre-processing, post-processing, scripting) Bonus Qualifications Fluency with Python Experience with CI/CD computing environments Experience with reactor systems codes, such as SAS4A/SASSYS-1, SAM, RELAP, TRACE, or GOTHIC Experience with qualification and validation of analyses Experience with subchannel analysis codes, such as DASSH, MOOSE-Subchannel, COBRA-TF, or similar Experience with high-fidelity computational fluid dynamics analysis We are looking for a Thermal-Hydraulics Methods Engineer that is: Passionate about clean energy Passionate about making advanced fission a reality Willing and able to learn quickly Knowledgeable about the fluid physics related to reactor cores and subchannel-level thermal-hydraulic (thermal fluids) analysis Eager to work on a dynamic team, receive constructive feedback, and grow with us Comfortable in a fast-paced, highly iterative environment Excited to think creatively, critically, and reflectively about the problems they are solving, while not leaning only on what has been done before An excellent writer who can write in modern active voice, so make your cover letter compelling and write it well! Able to communicate technical content and results verbally Who you are:
A startup person: You aren't driven by titles or hierarchy, and prefer efficiency to excess process. You don't need or expect to have a lot of guidance but you enjoy working in a fast-paced team. If you prefer the culture and feel of a large organization, that is great, but you likely won’t enjoy working with us! There is plenty of important work and plenty of good opportunities with organizations like that. Motivated:
You are self-motivated. You bring an enthusiasm to the team, and imbue a sense of passion that goes beyond clocking in and clocking out. This isn’t about a fake or arbitrary “pieces of flair” mentality or lack of work-life balance! It is about being a part of the vision and feeling a part of reaching team goals. A team-player:
Oklo genuinely is a team. We aren’t about taking credit for ourselves, and we aren’t about pushing blame to others. We do incredible things because we work as a team. An excellent communicator:
We need a person who is not only technically competent but also a clear and upbeat communicator. Creative:
Being creative means that when things fall outside clear scopes or processes or problems arise without clear solutions, you are able to identify it as well as invent ways to solve a problem or fill a need without micromanagement. The successful person in this job will not only be creative, but also enjoy being creative and solving open-ended problems which may change day-by-day. Detail-oriented: This focus is a big part of excellence, consistency, and quality. Even excellent grammar and spelling matter for both good communication as well as the image of the company that we put forward. Oklo requires remote employees to travel to headquarters (Santa Clara, CA) twice a quarter annually, based on business or team needs, including attendance at team meetings, off-sites, and other company events or gatherings. Some travel to other sites is also required for this position. Oklo offers flexible time off, equity, competitive pay, 401k, health insurance, FSA, flexible work hours, and other benefits. We are looking to fill this position immediately! About Oklo Inc.:
Oklo Inc. is developing fast fission power plants to deliver clean, reliable, and affordable energy at scale; establishing a domestic supply chain for critical radioisotopes; and advancing nuclear fuel recycling to convert nuclear waste into clean energy. Oklo was the first to receive a site use permit from the U.S. Department of Energy for a commercial advanced fission plant, was awarded fuel material from Idaho National Laboratory, and submitted the first custom combined license application for an advanced reactor to the U.S. Nuclear Regulatory Commission. Oklo is also developing advanced fuel recycling technologies in collaboration with the U.S. Department of Energy and U.S. National Laboratories. #CHOP: Oklo’s Values
Collaboration : We go further, together. We bring diverse perspectives, listen actively, and build trust through transparency and respect. We work across disciplines, sharing ownership to turn complex challenges into shared successes. Humility : We are team players who act for the good of the company and for the world. We are focused on our mission, not personal recognition. Ownership : We take pride in what we do and how we do it. We are proactive in finding solutions and see tasks through to completion. We are committed to delivering on our promises to provide clean, reliable, and affordable energy. Pathfinding : We chart new ground where no path exists by approaching challenges with curiosity, courage, and creativity while navigating ambiguity. Recruitment Fraud Disclaimer
Oklo is aware of recent recruitment fraud attempts targeting job seekers. Please be cautious of anyone claiming to represent Oklo who does
not
contact you from an official Oklo email address. All legitimate communications from our recruiting team— including application updates, interview requests, and job offers — will come
exclusively
from an Oklo email. Oklo will never ask for sensitive personal information, payments, or account credentials during the hiring process. If you receive suspicious outreach or have concerns about the authenticity of any communication claiming to be from Oklo, please contact us through the official channels listed on our website. Create a Job Alert Interested in building your career at Oklo? Get future opportunities sent straight to your email. Accepted file types: pdf, doc, docx, txt, rtf Enter manually Accepted file types: pdf, doc, docx, txt, rtf LinkedIn Profile Website Are you legally authorized to work in the United States? * Select... Will you now or in the future require sponsorship for employment visa status? * Select... Export Control Question: * Select... The questions in this section are for the sole purpose of ensuring compliance with U.S. regulations concerning the export of controlled or protected technologies or information, including 10 CFR Part 810 and 15 CFR Parts 730-774. Oklo is required to obtain answers to these questions from job applicants to ensure Oklo's compliance with these export regulations. If you are a U.S. Person, the export control regulations will not limit the technical information that Oklo can share with you after you start work. If, however, you are not a U.S. Person, the export control regulations may restrict the technical information to which we can give you access until and unless Oklo acquires an export authorization or license from the US government. If you are offered a position, it will be dependent on Oklo being able to satisfy all of the applicable export control requirements for your position, including acquiring any necessary export authorizations or licenses from the US government. Please identify yourself as one of the following A, B, or C as describedbelow: * ________________________________________________________________________ A
. U.S. Person, which is defined for export control purposes as either: a U.S. national (one born in American Samoa or the Commonwealth of the Northern Mariana Islands) a U.S. lawful permanent resident (commonly referred to as a “green card holder”), or a protected person under the Immigration and Nationality Act (such as an individual who the U.S. government has granted asylum or refugee status) ________________________________________________________________________ B
.
Not a U.S. Person, as defined above,
and
affiliation as a citizen, national, or permanent resident of
only
countries listed in
List I below.This list is derived from 10 CFR Part 810, Appendix A, which is linked here . Because the U.S. government can change this list of countries at any time, please use the link to view the regulations in Appendix A instead of relying on the list below. List I Australia Germany Poland Austria Greece Portugal Bulgaria Ireland Canada Italy South Africa Colombia Japan Spain Croatia Korea, Republic of Sweden Cyprus Lithuania Turkey Egypt United Arab Emirates Morocco United Kingdom Finland Netherlands Vietnam France Norway The questions in this section are for the sole purpose of ensuring compliance with U.S. regulations concerning the export of controlled or protected technologies or information, including 10 CFR Part 810 and 15 CFR Parts 730-774. Oklo is required to obtain answers to these questions from job applicants to ensure Oklo's compliance with these export regulations. If you are a U.S. Person, the export control regulations will not limit the technical information that Oklo can share with you after you start work. If, however, you are not a U.S. Person, the export control regulations may restrict the technical information to which we can give you access until and unless Oklo acquires an export authorization or license from the US government. If you are offered a position, it will be dependent on Oklo being able to satisfy all of the applicable export control requirements for your position, including acquiring any necessary export authorizations or licenses from the US government. Please identify yourself as one of the following A, B, or C as describedbelow: * ________________________________________________________________________ A
. U.S. Person, which is defined for export control purposes as either: a U.S. citizen a U.S. national (one born in American Samoa or the Commonwealth of the Northern Mariana Islands) a U.S. lawful permanent resident (commonly referred to as a “green card holder”), or a protected person under the Immigration and Nationality Act (such as an individual who the U.S. government has granted asylum or refugee status) ________________________________________________________________________ B
.
Not a U.S. Person, as defined above,
and
affiliation as a citizen, national, or permanent resident of
only
countries listed in
List I below.This list is derived from 10 CFR Part 810, Appendix A, which is linked here . Because the U.S. government can change this list of countries at any time, please use the link to view the regulations in Appendix A instead of relying on the list below. List I Australia Germany Poland Austria Greece Portugal Belgium Hungary Romania Brazil Indonesia Slovakia Bulgaria Ireland Slovenia Canada Italy South Africa Colombia Japan Spain Croatia Korea, Republic of Sweden Cyprus Latvia Switzerland Czech Republic Lithuania Taiwan Denmark Luxembourg Turkey Egypt Malta United Arab Emirates Estonia Morocco United Kingdom Finland Netherlands Vietnam France Norway __________________________________________________________________________
C.
Not a U.S. Person, as defined in A above,
and
not a citizen, national, or permanent resident of
only
countries listed in List I in B, above. ________________________________________________________________________ Please identify yourself as one of the following A, B, or C as described above: *
Oklo encourages employees to travel twice a quarter annually to either headquarters or another designated location based on team/company needs or events. Are you willing/able to travel twice a quarter annually? * Select...
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Santa Clara, CA or remote Thanks for your interest in Oklo! We are searching for a Core Thermal-Hydraulics Methods Engineer to join our team. Position Description Thermal-Hydraulics Engineers at Oklo are responsible for analyzing fluid flow and heat transfer within a reactor and associated systems. This work includes engineering analyses of thermal-fluid dynamics, clear and thorough documentation of the analyses, as well as interfacing with design teams. A Core Thermal-Hydraulics Methods Engineer will contribute to the development, qualification, and validation of methods for modeling coolant flow within reactor cores using one-dimensional models and intermediate-fidelity subchannel models. Specific responsibilities may include: Modeling core thermal-hydraulic behavior using subchannel codes such as DASSH, or MOOSE-Subchannel one-dimensional systems codes such as SAS4A/SASSYS-1 or SAM first principles approaches and in-house flow network models Developing methods to analyze core thermal-hydraulic behavior at steady-state and during transients Developing and utilizing analysis methods that efficiently and effectively build confidence in a design Automation, verification, and validation of modeling and simulation tools in support of analyses Collaborating cross-functionally to define design requirements, and providing technical feedback to quick-iterating design teams Document work using modern tools and techniques, and write well-written, thoughtful technical reports Minimum Qualifications Bachelors, Masters, or PhD in a technical field, such as nuclear, mechanical, or aerospace engineering Proficiency with thermal-hydraulics (thermal fluids) analysis methods Core competencies in heat transfer, fluid dynamics, and thermodynamics first principles Experience with low-fidelity and intermediate-fidelity (e.g., porous body and correlation-based) models for heat transfer and fluid flow Experience with numerical methods and software development for heat transfer and fluid flow problems Experience with data processing (e.g., pre-processing, post-processing, scripting) Bonus Qualifications Fluency with Python Experience with CI/CD computing environments Experience with reactor systems codes, such as SAS4A/SASSYS-1, SAM, RELAP, TRACE, or GOTHIC Experience with qualification and validation of analyses Experience with subchannel analysis codes, such as DASSH, MOOSE-Subchannel, COBRA-TF, or similar Experience with high-fidelity computational fluid dynamics analysis We are looking for a Thermal-Hydraulics Methods Engineer that is: Passionate about clean energy Passionate about making advanced fission a reality Willing and able to learn quickly Knowledgeable about the fluid physics related to reactor cores and subchannel-level thermal-hydraulic (thermal fluids) analysis Eager to work on a dynamic team, receive constructive feedback, and grow with us Comfortable in a fast-paced, highly iterative environment Excited to think creatively, critically, and reflectively about the problems they are solving, while not leaning only on what has been done before An excellent writer who can write in modern active voice, so make your cover letter compelling and write it well! Able to communicate technical content and results verbally Who you are:
A startup person: You aren't driven by titles or hierarchy, and prefer efficiency to excess process. You don't need or expect to have a lot of guidance but you enjoy working in a fast-paced team. If you prefer the culture and feel of a large organization, that is great, but you likely won’t enjoy working with us! There is plenty of important work and plenty of good opportunities with organizations like that. Motivated:
You are self-motivated. You bring an enthusiasm to the team, and imbue a sense of passion that goes beyond clocking in and clocking out. This isn’t about a fake or arbitrary “pieces of flair” mentality or lack of work-life balance! It is about being a part of the vision and feeling a part of reaching team goals. A team-player:
Oklo genuinely is a team. We aren’t about taking credit for ourselves, and we aren’t about pushing blame to others. We do incredible things because we work as a team. An excellent communicator:
We need a person who is not only technically competent but also a clear and upbeat communicator. Creative:
Being creative means that when things fall outside clear scopes or processes or problems arise without clear solutions, you are able to identify it as well as invent ways to solve a problem or fill a need without micromanagement. The successful person in this job will not only be creative, but also enjoy being creative and solving open-ended problems which may change day-by-day. Detail-oriented: This focus is a big part of excellence, consistency, and quality. Even excellent grammar and spelling matter for both good communication as well as the image of the company that we put forward. Oklo requires remote employees to travel to headquarters (Santa Clara, CA) twice a quarter annually, based on business or team needs, including attendance at team meetings, off-sites, and other company events or gatherings. Some travel to other sites is also required for this position. Oklo offers flexible time off, equity, competitive pay, 401k, health insurance, FSA, flexible work hours, and other benefits. We are looking to fill this position immediately! About Oklo Inc.:
Oklo Inc. is developing fast fission power plants to deliver clean, reliable, and affordable energy at scale; establishing a domestic supply chain for critical radioisotopes; and advancing nuclear fuel recycling to convert nuclear waste into clean energy. Oklo was the first to receive a site use permit from the U.S. Department of Energy for a commercial advanced fission plant, was awarded fuel material from Idaho National Laboratory, and submitted the first custom combined license application for an advanced reactor to the U.S. Nuclear Regulatory Commission. Oklo is also developing advanced fuel recycling technologies in collaboration with the U.S. Department of Energy and U.S. National Laboratories. #CHOP: Oklo’s Values
Collaboration : We go further, together. We bring diverse perspectives, listen actively, and build trust through transparency and respect. We work across disciplines, sharing ownership to turn complex challenges into shared successes. Humility : We are team players who act for the good of the company and for the world. We are focused on our mission, not personal recognition. Ownership : We take pride in what we do and how we do it. We are proactive in finding solutions and see tasks through to completion. We are committed to delivering on our promises to provide clean, reliable, and affordable energy. Pathfinding : We chart new ground where no path exists by approaching challenges with curiosity, courage, and creativity while navigating ambiguity. Recruitment Fraud Disclaimer
Oklo is aware of recent recruitment fraud attempts targeting job seekers. Please be cautious of anyone claiming to represent Oklo who does
not
contact you from an official Oklo email address. All legitimate communications from our recruiting team— including application updates, interview requests, and job offers — will come
exclusively
from an Oklo email. Oklo will never ask for sensitive personal information, payments, or account credentials during the hiring process. If you receive suspicious outreach or have concerns about the authenticity of any communication claiming to be from Oklo, please contact us through the official channels listed on our website. Create a Job Alert Interested in building your career at Oklo? Get future opportunities sent straight to your email. Accepted file types: pdf, doc, docx, txt, rtf Enter manually Accepted file types: pdf, doc, docx, txt, rtf LinkedIn Profile Website Are you legally authorized to work in the United States? * Select... Will you now or in the future require sponsorship for employment visa status? * Select... Export Control Question: * Select... The questions in this section are for the sole purpose of ensuring compliance with U.S. regulations concerning the export of controlled or protected technologies or information, including 10 CFR Part 810 and 15 CFR Parts 730-774. Oklo is required to obtain answers to these questions from job applicants to ensure Oklo's compliance with these export regulations. If you are a U.S. Person, the export control regulations will not limit the technical information that Oklo can share with you after you start work. If, however, you are not a U.S. Person, the export control regulations may restrict the technical information to which we can give you access until and unless Oklo acquires an export authorization or license from the US government. If you are offered a position, it will be dependent on Oklo being able to satisfy all of the applicable export control requirements for your position, including acquiring any necessary export authorizations or licenses from the US government. Please identify yourself as one of the following A, B, or C as describedbelow: * ________________________________________________________________________ A
. U.S. Person, which is defined for export control purposes as either: a U.S. national (one born in American Samoa or the Commonwealth of the Northern Mariana Islands) a U.S. lawful permanent resident (commonly referred to as a “green card holder”), or a protected person under the Immigration and Nationality Act (such as an individual who the U.S. government has granted asylum or refugee status) ________________________________________________________________________ B
.
Not a U.S. Person, as defined above,
and
affiliation as a citizen, national, or permanent resident of
only
countries listed in
List I below.This list is derived from 10 CFR Part 810, Appendix A, which is linked here . Because the U.S. government can change this list of countries at any time, please use the link to view the regulations in Appendix A instead of relying on the list below. List I Australia Germany Poland Austria Greece Portugal Bulgaria Ireland Canada Italy South Africa Colombia Japan Spain Croatia Korea, Republic of Sweden Cyprus Lithuania Turkey Egypt United Arab Emirates Morocco United Kingdom Finland Netherlands Vietnam France Norway The questions in this section are for the sole purpose of ensuring compliance with U.S. regulations concerning the export of controlled or protected technologies or information, including 10 CFR Part 810 and 15 CFR Parts 730-774. Oklo is required to obtain answers to these questions from job applicants to ensure Oklo's compliance with these export regulations. If you are a U.S. Person, the export control regulations will not limit the technical information that Oklo can share with you after you start work. If, however, you are not a U.S. Person, the export control regulations may restrict the technical information to which we can give you access until and unless Oklo acquires an export authorization or license from the US government. If you are offered a position, it will be dependent on Oklo being able to satisfy all of the applicable export control requirements for your position, including acquiring any necessary export authorizations or licenses from the US government. Please identify yourself as one of the following A, B, or C as describedbelow: * ________________________________________________________________________ A
. U.S. Person, which is defined for export control purposes as either: a U.S. citizen a U.S. national (one born in American Samoa or the Commonwealth of the Northern Mariana Islands) a U.S. lawful permanent resident (commonly referred to as a “green card holder”), or a protected person under the Immigration and Nationality Act (such as an individual who the U.S. government has granted asylum or refugee status) ________________________________________________________________________ B
.
Not a U.S. Person, as defined above,
and
affiliation as a citizen, national, or permanent resident of
only
countries listed in
List I below.This list is derived from 10 CFR Part 810, Appendix A, which is linked here . Because the U.S. government can change this list of countries at any time, please use the link to view the regulations in Appendix A instead of relying on the list below. List I Australia Germany Poland Austria Greece Portugal Belgium Hungary Romania Brazil Indonesia Slovakia Bulgaria Ireland Slovenia Canada Italy South Africa Colombia Japan Spain Croatia Korea, Republic of Sweden Cyprus Latvia Switzerland Czech Republic Lithuania Taiwan Denmark Luxembourg Turkey Egypt Malta United Arab Emirates Estonia Morocco United Kingdom Finland Netherlands Vietnam France Norway __________________________________________________________________________
C.
Not a U.S. Person, as defined in A above,
and
not a citizen, national, or permanent resident of
only
countries listed in List I in B, above. ________________________________________________________________________ Please identify yourself as one of the following A, B, or C as described above: *
Oklo encourages employees to travel twice a quarter annually to either headquarters or another designated location based on team/company needs or events. Are you willing/able to travel twice a quarter annually? * Select...
#J-18808-Ljbffr