ML19319A842
| ML19319A842 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 12/24/1969 |
| From: | Dromerick A US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Boyd R US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 7912190898 | |
| Download: ML19319A842 (8) | |
Text
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R..S. Boyd, Assistant Director for Reactor Projects, DEL TRAB:
S. Levine, Assistaat Director for Reactor Tech
, DEL OCONRR MUCLEAR STATION UNITS 1, 2, mfd 3 - DCCKET NOS4'50-269', 50-270 AND 50-287 I
The : Babcock 'and Wilcox Topical Report, BAW-10008, Part 2, entitled,
" Fuel-Assembly Stress and Deflection Analysis for Loss-of-Coolant Accident and Seismic Excitation" has been reviewed. The repcrt
. presents information indicating that Babcock & Wilcox has investi-gated the effect of seismic and LOCA forces on reactor internals fuel assemblies. They ; consider, based on the results t'aerefrom, that their 850 We Class skirt supported reactor vessel fuel assen-i blies will perform satisfactorily under these forces.
The information presented is, however, not developed to the technical depth that would permit us to make an. independent determination as to the adequacy ot the applicant's design criteria, analysis procedures or results.
Considaring:he importance to reactor safety of the topics involved, and the fact that the report covers a whole class of reactors (with i
the exception that the specified seisste excitations evaluated were determined for the Oconse site) it is reconmended that the Nuclear Stessa System Supplier be required to explain and justify in detail
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his design criteria, analysis procedures and results achieved. To l~
this end, a meeting with the engineers that are responsible for the analysis and testing reported would be desirable.
It is recommended that this nesting be held after review of this report by our seismic consultant, Blume & Associates.
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A. W.-Droserick, Chicf Containment & Comycnent RT-915A Technology 3rsach DEL:C&CTE:K32/ FPS l
Enclosure:
bec:
S. Levine Distribution:
List of Questions R. C. DeToung Suppl. /
I A. W. Dromerick DRL Reading cc w/ enc 1:
K. R. Wichman' AD/RT Reading C. Long, DEL F. F. Schauer C&CTB Reading
'A. Schwencer,'t>RL J. P. Knight T. R. Wilson, DEL M. B. Fairtile l
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c QUESTIONS c5 BAW-10008, PA2T I a
1.0 Section 2.4 of the report which delineates the general structurai i
design criteria for fuel assemblies does not sufficiently define the stress and strate limits for the design basis earthquaite (Ost) and slausitaneses==1-hypothecimi earthgsake (NLE) and DX:A mor the meaner and entsat to which the cited limits provide aus assured mar 2in assinat failure for these loadings.
Please provide further information i
as indicated and answer the specific questions which follow:
A.
'DME Criterta 1.
Confirm that the type of strasses referred to in Parat.raph 1 are in the primary category as defined in Article 1 of A3tE Code,Section III.
Describe the bacis for establishing 757.
of the stress ruptura life of the meterial as a avserical limit and whether that limit is constructed gm the average stress or the minismus stress to produc2 ruptura at the cad of 100000 hours.
2.
Clarify whether the type of stresses referred to in Paragraph 2 are in the secondary eategory la the same context as above.
hre stresses exceed yield, are they calemtated on an equive-i l
last elastic basis, i.e., ;;r'--41aatte basis as ia section III7 Identify the source of the fatises curves used for each material of concera, e.g., Articia 4,Section III. hre fatigue data I
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Questions 2
R&W-10000, Pt. 2 l
are esployed which are not included in any codes or standards, I
specify whether a basic data curve is used or a design curve l
1shich tacorporates design / correction factors e.g., 2 on stress.
20 on cycles and correction for maxiassa effect of mean stress.
The statammer that strain limits will be set using no more than 901 of the material's fatigue life implies that you may usa less. Please clarify this statement and la addition, out-line the exact procedure (s) used in setting the strata limit (s).
Specify the number and type of cycles that have been established for design purposes and indicate the margin of safety that
' exists over the apected number and type of operation cycles to be expertenesd.
I 3.
Tor the combination of stresses in (1) and (2) above, specify the stress limit (s) that apply, e.g., 3 3, or g.
3.
Combined tecA and 1EE 1.
Clarify whet.her the applied stress referred to in Paragraphs 1 and 2 is.a primary stress, exclusively. What is the basis i
for establishing 85% of ultimate strength of the material as a numerical stresa limit! Is the ultimate strength referred to the same as the minimum tensile strength of the matsrial as specified in the appropriate ASE or ASTN material specifi-cation? Is this stress calculated on an elastic basis ? Please l
l provide the elastic' stresses corresponding to this limit for each of the materials of ecacarr. Furnish the corresponding strata limita ed' each matarial.
questione 3
1AW-10008, Pt. 2 i
2.
Identify the compoemats referred to in Faragraph 2 that 1
contribute to the stability of the control rod guide tubes.
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3.
Please provide the basis for the allowance of 357. of the l
critical beckling load as a limit.
Identify the theoretical coluss formulas used, i.e.. Euler or other.
2.0 Flease peitatively relats Figure 3 of the report to the i
figure (s) of BAW-10008. Part 1.
3.0 3riefly describe the analytical techniques that the PLA55 computer l
code utilises and its capabilities in relation to its employment on thh problem.
4.0 The model used to describe the dymanic behavior of the reactor l
vessel and internals is not described in enoush detail and related l
precisely enough to the actual structures involved to permit sa assessment of the accuracy by which the vessel and iatsraals have been analytically described. Provida a.
Engineering drawings or detailed sketches of the structural
{
features of importance.
b.
A precise description of the loestion of and basis for com-l patation of masses and section properties /ba=dary conditions.
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c.
Details on the saamer in which flexibility coefficients have l
been co m ted and the results achieved.
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-Queetione' 4
BAni-10008, Pt. 2 1-3.0 The desiga loadings and their scener of application to the structure l
require more precise description. Provida:
i a.
The complete digitalized acceleration record that was used la the analysis.
)
b.-
The relative sequencing of the IDCA and seismic. loads and L
the basis for the sequencing used.
c.
A Bea6ral description of the menner of digital-to-analog conversione of data, an estimate of the accuracy of the l
process and a description by which the acceleration was laserted into the electronic differential smalyser.
d.
A complete acceleration respcase spectra comparison at one and tea per ccat critical damping.
e.
The manner in which the vertical seismic ccaponent has
- been factored into the analysis and the 1:sportsace of the l
stresses and deflections therefrom with respect to the l
horiscatal seismic and LOCA loadings.
6.0 The manner in which analog (electronic differential analyzer) computations have been performed is not presamte/..
Provide:
\\
s The equations of motias for the model used (the matrix format a.
ney be used but all almesats should be indicated).
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1
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l Queaticas 5
l BAW-10008, Pt. 2 l
b.
N time and magnitude scaled equations of motion for the idu11ains lumped mass system.
~
The numerical values used for the mess, stiffness and da e c.
tag matrices.
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d.
A detailed description of the manmer in which individual desping coefficiants have been determined to include a sample
't
, calculation indicating the procedure used.
+
A tabulation of poteatiometer and initial valns settings.
e.
f.
A detailed descriptica of the accual analog setup used to include a flow chart showing the summes,integrators, pots.
noe linear components med digital components involved, g.
N strip chart recorder output results for several typical tuas.
h.
A tabulation of significant stress, straia and deflection results at critical locations.
i 1
7.0 Please provide a sketch of second model segment (as discussed in Section 4.1.4 of the report) and discuss its interactice with the first t
model segment.
3.0 Section 5.1 of the report discusses the frequency and damping c
- tests performed for full size and subsised specissans. -Further detailed t
t Queations-6' i
~8NJ-10008. Pt. 2:
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i information is required co complete our review.
Picasa provide discussion l-l of 'the. following:
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l
~ a.
The basis for test amplitudes and frequencies used.
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b.
-A description of.and bases for the type of loadings used i
including test fixtures employed.
i c.
A detailed description of the full size and substzed specimens used including ie identification of specimen materials,
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d.
Description of test data obtained.
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l-e.
Interpretation and analysis of results.
'9.0 In reference to the spacer grid compression tests described in Section 5.3, please provide a sketch showing the test specimen, its
' orientation in the loading fixture, and the direction of Icading.
Explaim how corrections were made for temperature effects.
Please provide elaboration on the load cycling phenomenon noted in Paragraph i
2 and show graphically how this occurs.
10.0
' Horisontal contact 'analysia : esults are given in Section 6.1 in l
l terms of. margins of safety calculated on the basis of allowable and applied. loads. Please provide the maximum atresses that were calcu-
~ 1 aced from the' applied loads for the applicabic components in both Gections 6.1 and 6.2.
Specify how LOCA and seismic stresses are
-combined.
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j Queatines 7
RAW-10008 Pt. 2 11.0 Section 6.2.1.2 shows the margia of safety for guide tube buckling under LOCA loadings only. What is the margia of safety for combined LOCA and seismic loads ? In addition, it is not explicit that seismic loads are included in the reported results of Section 5.2, vertical i
j contact analysis; please confirm that seismic loads are included.
1 1
12.0 Flease provida a detailed axplanation for conclusion that loads li due to LOCA and/or earthquaka are act additive to those due to normal i
operation because the nex1== loeda are limited by the available friction j
loads between the end grids and the fon t rods (section 6.2.2.1).
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