Attachment_5_TO_1_SOW.pdf

Version Control Date: April 30, 2014

TASK ORDER 1 STATEMENT OF WORK

1. PROJECT TITLE

This is a non-personal services task order to provide Computational Fluid Dynamics (CFD) Modeling and Simulation Support for Gas Mixing Studies in Simple Geometry.

2. BACKGROUND

Nuclear safety applications are beginning to use thermal-hydraulic analyses and computational fluid dynamics (CFD) codes (e.g., FLUENT or STAR-CCM+) to demonstrate the adequacy of systems behavior during accident scenarios in light water reactors. The U.S. Nuclear Regulatory Commission (NRC) wants to develop practical advice for achieving high-quality CFD simulations. Deficiencies and inaccuracies of CFD simulations can be related to a wide variety of errors and uncertainties. An error is a recognizable deficiency that is not caused by a lack of knowledge; an uncertainty is a potential deficiency that is caused by lack of knowledge. An error is something that can be removed with proper care, effort, and resources; an uncertainty cannot be removed because it is rooted in a lack of knowledge. This task order addresses CFD modeling uncertainties. The difference between the real flow and the exact solution of the model equations creates these uncertainties.

NRC expects to participate in a benchmark exercise for an upcoming CFD workshop. The chosen benchmark will be used to evaluate uncertainty for a CFD prediction. This will involve an experiment performed in the GEMIX (General Mixing Experiment) facility at Paul Scherrer Institute (PSI) in Villigen, Switzerland. GEMIX focuses on the basic mechanisms, such as turbulence, that promote or define mixing over a stratified density interface. The 2016 CFD workshop CFD4NRS-6 will be held at MIT in Boston, MA in September. Throughout the remainder of this statement of work, GEMIX will be referred to as Facility 1.

3. OBJECTIVE

The primary objective of this task order is to apply a CFD code to predict sets of test scenarios in Facility 1. The contractor shall predict up to two test scenarios. The scenarios will utilize different gas flows and/or densities.

4. APPLICABLE DOCUMENTS AND STANDARDS

Organization for Economic Co-operation and Development (OECD) publication. Best Practice Guidelines for the use of CFD in Nuclear Reactor Safety Applications is available at http://www.oecd-nea.org/nsd/csni/cfd/.

5. SCOPE OF WORK

The contractor shall build a CFD model of the test facility using geometry provided by the Contracting Officer’s Representative (COR) upon task order award. The CFD codes required will be one of those currently used by the NRC staff. This includes the most recent versions of either the FLUENT or the STAR-CCM+ code. The facility is comprised of a flow channel (approximately 0.1m x 0.1m cross section with 1.0 m length) fed by two flow streams of different density. Boundary and initial conditions including, description of facility, description of data, and specific results of test scenarios from experiments conducted at Facility 1 for the simulation will also be provided by the COR upon task order award. Specific development of model features such as, the test section and upstream flow channels, may be necessary. Turbulent mixing of two streams at different densities in the test scenarios shall be studied. A grid convergence study shall be completed along with an estimate of the grid convergence index (GCI). If necessary, modifications to the turbulent modeling approach shall be completed such as, the impact of density stratification on turbulent mixing of horizontally stratified layers.

Utilize the CFD model to predict specific variables in the test scenarios at locations provided by the COR. Perform sensitivity studies (e.g., time step, modeling inputs) as appropriate and approved by COR. Using results provided by the COR, the predictions and uncertainty shall also be compared to the available predictions and uncertainty from other related to CFD predictions, if available. Where deviations from the test data are evident, possible explanations shall be considered and documented as a guide for further studies and model development.

The contractor shall develop, validate, and document a base CFD model and suitable user-defined coding (such as FLUENT user defined functions), where necessary. The user-defined coding may be required to account for significant phenomena related to the scenarios that may not be included explicitly in the code. In addition, user-defined coding may be needed to automate the collection of transient predictions at key points in the solution domain. The documentation shall include solver settings, solver options, and modeling choices, as well as a detailed outline of the logic and physics included in any user-defined code. The code developed for the physical models and/or data analysis shall be modular and well documented so that it can be easily modified for related modeling efforts. The NRC requires four weeks to review and comment on the base model and user-defined code. COR approval of the base model and user-defined code is required prior to performing the grid convergence or uncertainty quantification (UQ) efforts.

In addition to the predictions, a method to estimate uncertainty in these predictions shall be utilized to quantify the modeling uncertainty. The contractor shall develop a report that describes the methodology planned for performing UQ for CFD application to mixing problems with density effects (buoyancy/stratification) for one of the selected scenarios as determined by the COR.

The methodology should be based on some industry standard approach such as the ASME V&V 20 standard. The report shall include the estimated effort to perform the UQ, the number of code runs required, and any assumptions or limitations in the approach. COR approval of the report is required prior to performing the uncertainty calculations.

The contractor shall prepare and submit a comprehensive draft technical report that documents the CFD model, modeling options, user-defined coding, turbulence methods, grid sensitivity study, uncertainty approach and results, application of best practice guidelines, sensitivity studies, and the final predictions. This report shall summarize all comparisons made with the test data and make recommendations for further model sensitivity studies or methods that might improve the accuracy of the results or the efficiency of the approach.

The contractor shall prepare and submit a final technical report that incorporates review comments provided by the COR on the draft technical report.

6. DELIVERABLES AND DELIVERY SCHEDULE

Deliverable and Acceptance Criteria Deliverable Format Due Date Base CFD Model(s) and user- defined coding

Format suitable for running on the NRC LINUX computer systems

3 months after award of task order

Base Model and user-defined code Report

Acceptance Criteria: Report contains all required information

Microsoft Word Document and/or Adobe PDF

4 months after award of task order

Uncertainty Quantification Methodology Report

Acceptance Criteria: Report contains all required information

Microsoft Word Document and/or Adobe PDF

5 months after award of task order

Draft Technical Report

Acceptance Criteria: Report contains all required information

Microsoft Word Document and/or Adobe PDF

9 months after award of task order

Final Technical Report

Acceptance Criteria: All COR comments are addressed.

Microsoft Word Document and/or Adobe PDF

45 calendar days after receipt of COR comments

Revised CFD model(s) along with all user-defined coding used in the modeling and post processing effort

Format suitable for running on the NRC LINUX computer systems

9 months after award of task order

Monthly letter status report (MLSR) per Section C.13 of the base contract.

Acceptance Criteria: MSLR is complete and contains all required information.

Microsoft Word Document and/or Adobe PDF

NLT 20th day of the month

The contractor is responsible for structuring the deliverables to follow agency standards. The current agency standard software for developing documents is Microsoft Office Suite 2010, including Word 2010 for text documents (.docx) and Excel 2010 for spreadsheets (.xlsx). The current agency Portable Document Format (.pdf) standard is Adobe Acrobat XI Pro.

Deliverables shall be submitted free of spelling and grammatical errors and conform to requirements stated in this SOW. The format of reference lists and of citations of references in text shall conform to guidance provided by the COR.

The above deliverables shall be provided electronically and in hard copy (upon request) to the COR and NRC’s Project Technical Lead. The MLSR must also be submitted to the following addresses:

Contracting Officer NRC Administrative Management Division at: ContractsPOT.Resource@nrc.gov, RESDSAMLSR.Resource@nrc.gov

7. TECHNICAL QUALIFICATIONS REQUIRED

Specialized experience shall include expertise in such areas as data manipulations, CFD model development, verification and validation exercises, CFD benchmarking studies, user-defined coding development for CFD models, two-phase CFD modeling, general fluid mixing and turbulence modeling and knowledge and familiarity with the Best Practice Guidelines for the use of CFD in Nuclear Reactor Safety Applications.

Personnel working under this task order shall meet the minimum requirements for experience and education, as follows:

• Project manager or equivalent:

Shall have at least 3 years of project management experience. Shall also have a bachelor's or higher degree from an accredited school.

• Sr. Engineer/Scientist (equivalent):

Shall also have a bachelor's or higher degree in a science or engineering field from an accredited school with at least a minimum of 10 years professional experience.

• Engineer/Scientist (equivalent):

Shall also have at least a bachelor's degree in a science or engineering field from an accredited school with at least a minimum of 3 years professional experience.

• Quality Assurance (QA) person Shall also have at least a bachelor's degree in a science or engineering field from an accredited school with at least a minimum of 3 years of experience performing QA on

CFD.

8. KEY PERSONNEL

The following personnel are considered key personnel by the Government:

Sr. Engineer/Scientist (equivalent) Engineer/Scientist (equivalent)

9. MEETINGS AND TRAVEL

No travel is anticipated to occur under this task order.

Meetings are anticipated to occur between the contractor, COR and other NRC technical staff, via teleconference, periodically to discuss project status.

10. MATERIALS REQUIRED

The following software is required throughout the life of this task order:

The contractor shall be required to maintain a license to use the CFD software. The contractor shall be required to maintain the same version of the CFD software as the NRC. The NRC currently owns FLUENT version 15 and STAR-CCM+ version 10.

11. GOVERNMENT-FURNISHED PROPERTY/INFORMATION

GFP ITEM Date provided to Contractor Method of Shipment Geometry of Facility

Upon Task Order Award Electronic

Boundary and Simulation Conditions

Upon Task Order Award Electronic

Test Data

As available to the COR Electronic

12. PLACE OF PERFORMANCE

The work performed under this task order is expected to occur at the contractor’s facility.

13. PERIOD OF PERFORMANCE

The period of performance is task order award through the following twelve (12) months.

14. SECURITY

The contractor may be provided access to and incorporate into the deliverables Sensitive Unclassified Non-Safeguards Information (SUNSI).

15. RESEARCH QUALITY

The quality of NRC research programs are assessed each year by the Advisory Committee on Reactor Safeguards. Within the context of their reviews of RES programs, the definition of quality research is based upon several major characteristics:

Results meet the objectives (75% of overall score) Justification of major assumptions (12%) Soundness of technical approach and results (52%) Uncertainties and sensitivities addressed (11%) Documentation of research results and methods is adequate (25% of overall score) Clarity of presentation (16%) Identification of major assumptions (9%)

It is the responsibility of the contractor to ensure that these quality criteria are adequately addressed throughout the course of the research that is performed. The NRC COR will review all research products with these criteria in mind.