Lesson 9: Structure of an NCSE

Outline   Accident presentations   LA report in Public area   Structure of an NCSE   Example DOC in Public area

Accident presentations

Accident presentation   LA report in Public area   Use but not ONLY. Do some (internet) research   Not only the descriptions in LA-13638, but also look at p and Appendix B   Assignments and instructions in Public area

Structure of an NCSE

Cover sheet   Strict format: see example   Evaluation is YOUR first three initials plus -01

Outline of Typical CSE  Introduction  Description of process  Computational methodology  Discussion of contingencies  Evaluation and results  Design features and administrative controls  Summary & conclusions  Appendices

Introduction  Why the work is being done  Revision history  Necessary administrative boilerplate

Outline of Typical CSE  Introduction  Description of process  Computational methodology  Discussion of contingencies  Evaluation and results  Design features and administrative controls  Summary & conclusions  Appendices

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.  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

Outline of Typical CSE  Introduction  Description of process  Computational methodology  Discussion of contingencies  Evaluation and results  Design features and administrative controls  Summary & conclusions  Appendices

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) Basis of criticality control (k-safe)  Boilerplate on the codes used  Description of the computer used Point to the verification document Point to the verification document  Summarize validation and point to the Validation appendix

Outline of Typical CSE  Introduction  Description of process  Computational methodology  Discussion of contingencies  Evaluation and results  Design features and administrative controls  Summary & conclusions  Appendices

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

Discussion of contingencies (2)  Summarized in the table  Mass: Normal and Contingency should have included his actual mass limits (3.1*1.2 and 3.1*1.2*2 kg)  Geometry: Should have said cylinder  Enrichment: Normal should have said 100%, not N/A  Volume: Should have done the math under Normal and said 4.4 L

Discussion of contingencies (3)  There is one subsection per MAGICMERV parameter  All contingencies in the category should be listed and described  Each should include a statement of why it is unlikely  Student was counted off for saying UNUSED parameters were “not considered as a contingency” rather than “not controlled”

Outline of Typical CSE  Introduction  Description of process  Computational methodology  Discussion of contingencies   Evaluation and results  Design features and administrative controls  Summary & conclusions  Appendices

Evaluation and results  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

Evaluation and results (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

Evaluation and results (3)  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)

Table x. Calculational Results Case Description column(s) keff k-eff+2  21

Outline of Typical CSE  Introduction  Description of process  Computational methodology  Discussion of contingencies  Evaluation and results  Design features and administrative controls  Summary & conclusions  Appendices

Design features and administrative controls  Description of:  Engineered safety features  Posted controls  Most important and most often referred to  Very controlled format  Control 7.x.x: Actual posting wording  Basis: Follow the example, pointing back to the text  In addition, Appendix C contains PowerPoint slide examples of the Postings themselves

WHAT you control  Limits are set so that criticality cannot occur when operators comply with the limits  Examples  Mass limit is 350 g 235 U (i.e., maximum mass)  Mass limit is 200 g 239 Pu (i.e., maximum mass)  Concentration limit is 1 g 235 U/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)

HOW you control  The example did NOT use Engineered safety features, which I like to see  Remember our preference 1. Passive control: railroad bridge over highway 2. Active control: lights and gate at railroad crossing 3. Administrative: stop sign at railroad crossing

Design features and administrative controls (2)  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

Outline of Typical CSE  Introduction  Description of process  Computational methodology  Discussion of contingencies  Evaluation and results  Postings & controls  Summary & conclusions  Appendices

Summary & conclusions  Summary  Conclusions

Appendices  A. Materials and compositions  B. Input and output listings  C. Postings  D. Comment review sheets (N/A)  E. Validation check sheets (N/A)  F. IDC Listing for wet residues (N/A)  G. Validation report  H. Parametric studies

Final report requirements In the final report, you need to add the remaining sections:  Section 8, Summary and conclusions  References  App. A, Material and geometry descriptions  App. B, Input and output listings  App. D, Comment review sheets  App. G, Validation Plus, clean up the other sections based on my comments The Final Report MUST stand alone—no cutting and pasting required by the professor!

Parametric study example (worksheet) 31

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

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

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!)

 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) Postings

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

Summary & conclusions  Summary  Conclusions

Appendices: Follow examples  A. Materials and compositions  B. Input and output listings: Use COURIER NEW font for listings  C. Postings: WYSIWYG using colors  D. Comment review sheets (Deleted - no longer required)  E. Validation check sheets (Deleted - no longer required)  F. IDC Listing (Deleted - no longer required)  G. Validation report: Which we covered last time  H. Parametric studies: See following slides 38

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.

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 40

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 41

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? 42