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Lesson 9

Lesson 9. Description of projects Accident presentations Overview of NCSE. Project description. Project description. Project description (2). Project description (3). Structure of an NCSE. Cover sheet. Strict format: see example. Outline of Typical CSE. Introduction

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Lesson 9

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  1. Lesson 9 • Description of projects • Accident presentations • Overview of NCSE

  2. Project description

  3. Project description

  4. Project description (2)

  5. Project description (3)

  6. Structure of an NCSE

  7. Cover sheet • Strict format: see example

  8. Outline of Typical CSE • Introduction • Description of process • Computational methodology • Discussion of contingencies • Normal & accident analysis • Postings & controls • Summary & conclusions • Appendices

  9. Introduction • Why the work is being done • Revision history • Necessary administrative boilerplate

  10. Outline of Typical CSE • Introduction • Description of process • Computational methodology • Discussion of contingencies • Normal & accident analysis • Postings & controls • Summary & conclusions • Appendices

  11. Description of process • Necessary description of the process • Overview of the procedural steps • Important interactions with preceding and following processes (and any others) • Necessary description of the hardware • Gloveboxes, canisters, storage racks, etc. (Include pictures) • Relative positions, etc. • Special materials • Different variations allowed in geometry and process (important to criticality) • Compare to the Contingency Table to make sure that all of the relevant MAGICMERV normal parameters are mentioned

  12. Outline of Typical CSE • Introduction • Description of process • Computational methodology • Discussion of contingencies • Normal & accident analysis • Postings & controls • Summary & conclusions • Appendices

  13. Computational Methodology • Non-KENO • Indication that relying on ANS-8.1 limits and/or hand calculational techniques • KENO • Indication that relying on criticality calculations+ • Basis of criticality control (k-safe) • Boilerplate on the codes used • Description of the computer used • Point to the verification document • Summarize validation and point to the Validation appendix

  14. Outline of Typical CSE • Introduction • Description of process • Computational methodology • Discussion of contingencies • Normal & accident analysis • Postings & controls • Summary & conclusions • Appendices

  15. Discussion of contingencies • Parametric review: Checklist of parameters important to criticality in THIS analysis • mass, absorbers, geometry, interaction, concentration, moderation, enrichment, reflection, volume • Contingency analysis • Definition of normal case vs. parameters • Definition of credible accidents vs. parameters • Contingency table including controls

  16. Outline of Typical CSE • Introduction • Description of process • Computational methodology • Discussion of contingencies • Normal & accident analysis • Postings & controls • Summary & conclusions • Appendices

  17. Normal & accident analysis • Materials discussion, including assumptions (point to appendix) • Normal Model development • Normal & accident • Simplified through the use of parametric studies • Contingency case models as variation on normal model

  18. Normal & accident analysis (2) • JUST DO IT: Calculate the normal case and each of the contingencies you have identified • Table of results that stands alone • Like Tables in Section 6.4 of ExampleCSE • Enough column to differentiate cases (repeat columns from contingency table, if desired) • Keff+/-sigma column AND Keff+2sigma column • Mark the limiting case with BOLD or larger font (or both) • Discuss results in text

  19. Analysis phase • Table of results that stands alone • Like Tables in Section 6.4 of ExampleCSE • Enough column to differentiate cases (repeat columns from contingency table, if desired) • Keff+/-sigma column AND Keff+2sigma column • Mark the limiting case with BOLD or larger font (or both)

  20. Table x. Calculational Results 20

  21. Outline of Typical CSE • Introduction • Description of process • Computational methodology • Discussion of contingencies • Normal & accident analysis • Postings & controls • Summary & conclusions • Appendices

  22. Postings & controls • Description of: • Engineered safety features • Administrative controls • Operator aids • Procedural changes • Postings • Most important and most often referred to • Very controlled format • Posting • Basis

  23. WHAT you control • Limits are set so that criticality cannot occur when operators comply with the limits • Examples • Mass limit is 350 g 235U (i.e., maximum mass) • Mass limit is 200 g 239Pu (i.e., maximum mass) • Concentration limit is 1 g 235U/liter (i.e., maximum concentration) • Moderation limit is H/U = 4 (i.e., maximum moderation) • Volume limit is 4 liters (i.e., maximum volume) • Container limit is 4 containers (i.e., maximum number of containers) • Spacing limit is 2 feet (i.e., minimum spacing) • Stacking limit is 4 high (i.e., maximum number of items in a stack)

  24. HOW you control • Your NCSE will include the following sections: 7.1 Engineered safety features 7.2 Procedural requirements 7.3 Postings • Remember our preference • Passive control: railroad bridge over highway • Active control: lights and gate at railroad crossing • Administrative: stop sign at railroad crossing

  25. Control Selection • Passive engineered control examples • Mass: container design (i.e., limit container size) • Absorption: solid poisons (Raschig rings, boron-Al plates • Geometry: container design (slab tanks, pencil tanks, bottle diameter) • Interaction: spacers (storage racks, bird cages, carts) • Moderation: sealed containers or systems (covers on storage racks to exclude sprinkler water) • Reflection: spacers (storage racks, bird cages) • Volume: container design

  26. Writing Controls • Clear • Concise • Unambiguous • Doable • Simple and easy to perform • Directly controllable by operator • Language that an operator will understand • Relates to upset/change that needs to be prevented

  27. Procedures- General • Procedures provide instructions to perform tasks: • Administrative • Technical • Maintenance • Emergency • Ranked according to safety significance • Procedures for fissionable material operations are reviewed by NCS Engineers • Should be scheduled • Comments should be documented • Comment resolution/procedure approval is documented • Good “conduct of operations” requires verbatim compliance with procedures (so make sure it is possible!)

  28. Postings • Immediate information that the operator would NOT be expected to remember from training • Very controlled format in Sect. 7 • Control • Basis: Tied directly to Section 5 (Do not add or subtract) • Similarly controlled format in the posting itself: • Important words CAPITALIZED and possibly in a stand-out color • Few articles (a, an, the) • No convoluted IF/THEN syntax (KISS)

  29. Postings • As we discussed before, Section 7 contains the postings and basis for each • In addition, Appendix C contains PowerPoint slide examples of the Postings themselves

  30. Outline of Typical CSE • Introduction • Description of process • Computational methodology • Discussion of contingencies • Normal & accident analysis • Postings & controls • Summary & conclusions • Appendices

  31. Summary & conclusions • Summary • Conclusions

  32. Appendices • A. Materials and compositions • B. Input and output listings • C. Postings • D. Comment review sheets • E. Validation check sheets (Deleted - no longer required) • F. Validation report • G. Parametric studies

  33. Appendix C: Postings (Example) • Nuclear Criticality Safety Limits and Controls • NO MORE than 4300 kg Plutonium per 8-liter container. • •NO MORE than ONE operator may carry ONE 8-liter container at a time to the drum loading area.

  34. App. H: Parametric Studies • Stand alone pre-analysis studies in order to refine the normal case (What is normal?) • Ideal: Perturbations on limiting case • At minimum: • PS#1 = Worst case of concrete • PS#2 = 12” of water is infinite • PS#3 = 6% water for sprinkler is conservative • Follow format of AppendixH.doc in public area 34

  35. Parametric studies • Arise out of modeling questions • Most reactive material makeup • Most reactive reflection • Most reactive placement of fissile (primary) • Most reactive arrangement of other material (including other fissile elements) • Acceptability of modeling simplification (e.g., leaving out walls, ceilings, etc.) • Sometimes order matters—you want to clear up the most “independent” modeling questions first to use in the others 35

  36. Parametric study example • You are analyzing storage of four 10 liter canisters in a 90x90x90 cm glovebox against a wall (Pu-239/water mixture) • Assume the “normal” case still has the following ambiguities: • H/D range of .8 to 1.2 • Placement of canisters in glovebox • Type of concrete (among 4 SCALE choices) • Optimum H/X ratio • What parametric studies would you run? • In what order? 36

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