Lesson 9: Structure of an NCSE
Outline
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Accident presentations
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LA report in Public area
Structure of an NCSE
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Example DOC in Public area
Accident presentations
Accident presentation
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LA report in Public area
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Use but not ONLY. Do some (internet)
research
Not only the descriptions in LA-13638, but also
look at p. 57-67 and Appendix B
Assignments and instructions in Public area
Structure of an NCSE
Cover sheet
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Strict format: see example
Evaluation is YOUR first three initials plus
-01
Outline of Typical CSE
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Introduction
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Description of process
Computational methodology
Discussion of contingencies
Evaluation and results
Design features and administrative controls
Summary & conclusions
Appendices
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Introduction
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Why the work is being done
Revision history
Necessary administrative boilerplate
Outline of Typical CSE
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Introduction
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Description of process
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Computational methodology
Discussion of contingencies
Evaluation and results
Design features and administrative controls
Summary & conclusions
Appendices
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Description of process
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Necessary description of the process
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Necessary description of the hardware
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Overview of the procedural steps
Important interactions with preceding and following
processes (and any others)
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
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Introduction
Description of process
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Computational methodology
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Discussion of contingencies
Evaluation and results
Design features and administrative controls
Summary & conclusions
Appendices
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Computational Methodology
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Non-KENO
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Indication that relying on ANS-8.1 limits
and/or hand calculational techniques
KENO
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Indication that relying on criticality
calculations+
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Boilerplate on the codes used
Description of the computer used
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Basis of criticality control (k-safe)
Point to the verification document
Summarize validation and point to the
Validation appendix
Outline of Typical CSE
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Introduction
Description of process
Computational methodology
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Discussion of contingencies
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Evaluation and results
Design features and administrative controls
Summary & conclusions
Appendices
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Discussion of contingencies
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Parametric review: Checklist of parameters
important to criticality in THIS analysis
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Contingency analysis
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mass, absorbers, geometry, interaction, concentration,
moderation, enrichment, reflection, volume
Definition of normal case vs. parameters
Definition of credible accidents vs. parameters
Contingency table including controls
Discussion of contingencies (2)
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Summarized in the table
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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)
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There is one subsection per MAGICMERV
parameter
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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
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Introduction
Description of process
Computational methodology
Discussion of contingencies
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Evaluation and results
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Design features and administrative controls
Summary & conclusions
Appendices
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Evaluation and results
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Materials discussion, including assumptions
(point to appendix)
Normal Model development
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Normal & accident
Simplified through the use of parametric studies
Contingency case models as variation on
normal model
Evaluation and results (2)
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JUST DO IT: Calculate the normal case and each
of the contingencies you have identified
Table of results that stands alone
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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)
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Table of results that stands alone
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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
s
k-eff+2s
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Outline of Typical CSE
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Introduction
Description of process
Computational methodology
Discussion of contingencies
Evaluation and results
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Design features and
administrative controls
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Summary & conclusions
Appendices
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Design features and
administrative controls
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Description of:
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Most important and most often referred to
Very controlled format
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Engineered safety features
Posted controls
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
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Limits are set so that criticality cannot occur
when operators comply with the limits
Examples
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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)
HOW you control
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The example did NOT use Engineered safety
features, which I like to see
Remember our preference
Passive control: railroad bridge over highway
2. Active control: lights and gate at railroad crossing
3. Administrative: stop sign at railroad crossing
1.
Design features and
administrative controls (2)
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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
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Introduction
Description of process
Computational methodology
Discussion of contingencies
Evaluation and results
Postings & controls
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Summary & conclusions
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Appendices
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Summary & conclusions
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Summary
Conclusions
Appendices
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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)
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Control Selection
Passive engineered control examples
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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
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Clear
Concise
Unambiguous
Doable
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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
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Procedures provide instructions to perform tasks:
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Procedures for fissionable material operations are reviewed
by NCS Engineers
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Administrative
Technical
Maintenance
Emergency
Ranked according to safety significance
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!)
Postings
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Immediate information that the operator would
NOT be expected to remember from training
Very controlled format in Sect. 7
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Control
Basis: Tied directly to Section 5 (Do not add or
subtract)
Similarly controlled format in the posting itself:
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Important words CAPITALIZED and possibly in a
stand-out color
Few articles (a, an, the)
No convoluted IF/THEN syntax (KISS)
Outline of Typical CSE
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Introduction
Description of process
Computational methodology
Discussion of contingencies
Normal & accident analysis
Postings & controls
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Summary & conclusions
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Appendices
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Summary & conclusions
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Summary
Conclusions
Appendices: Follow examples
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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
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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
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Stand alone pre-analysis studies in order to
refine the normal case (What is normal?)
Ideal: Perturbations on limiting case
At minimum:
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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
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Parametric studies
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Arise out of modeling questions
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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
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Parametric study example
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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:
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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?
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