ML20037B569
| ML20037B569 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 06/12/1973 |
| From: | Skovholt D US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Butterfield L COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8010170761 | |
| Download: ML20037B569 (8) | |
Text
{{#Wiki_filter:Distribution Docket file AEC PDR RP Reading Branch Reading DJSkovhcit, L:0R ACRS (16) i ~,.
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R0 (2) DLZiemann, L:0R #2 l>ocket l'o. 50-10 TJCarter, L:0R # PJ:Diggs, L:0R #2 I Commonwealth Edison Company ATTH: Mr. L. D. Butterfield, Jr. Nuclear Licensing Administrator Post Office Box 767 Chicago, Illinois 60690 Gentle:acn: In connection with our ongoing review of Report No. GU-5293, " Evaluation of Densification in Dresden Unit 1 Fuel Supplied by Gulf United," dated February 23, 1973, we find that the additional information identified in the enclosed pages is needed to complete our review. We request that you submit this information before June 22, 1973, with one original and 39 additional copics. Sincerely, 1 Donald J. Skovholt Assistant Director for Operating Paactors Directorate of Licensing
Enclosure:
Request for Information cc w/ enclosure: John U. Rouc, Lsquire 1chan, Lincoln 6 Ecale Counselors at Law One First Marinnn1 Plaza Chicago, Illinois 60670 ggcDavis VRooney D. Ros{ Rt.'Reid d : 0 R, N,,l,, ,L10,R,,,f,2,,,,,j,,,li ,,,Lj,g,R,,,p2 ,,,L ; Q,g,-{,[,,,,,., cmet > 2 i ,J. RD511ver:rwg' RI:R c'i d.. ~4., p.D.3iggs DLZiemann DJSkovho3t s. % i vc p. . I.. ! 6/ f' /7. 6/ u 7: l 6/
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CQ W NWEALTH EDISCN COMPANY DRESDEN UNIT I EOCKET NO. 50-10 REQUEST FOR ADDITIONAL INFORMATION ON FUEL DENSIFICATION 1. Powder Preparation - provide the chemical process for powder preparation. t Describe in detail any heat treatment or cominution treatment of the powder. 2. Powder Properties'- provide the noninal mean particle diameter, particle size distribution, specific surface of the powder, and variation of these
- properties from batch to batch. Provide chemical analyses including oxygen /
netal ratios, absorbed gases, netallic and ncnmetallic impurities. 3. Pressing Parameters - provide the pressures used, type of dies and presses used, green pellet densities (mean values and standard deviations), binders and additives used and in what quantities, and how the additions were made. 4. Sintering Parameters - provide a complete description of the sintering cycle including heating rates, soak times, and cooling rates. Include the atmosphere and approximate concentration of impurities in the furnace. 5. Surface Finishing - provide the methods used to finish the pellets and the specifications for the finish. 6. Resintering Parameters - describe the pellet reheating procedure including the heating cycle. Cite reasons for choice of particular temperatures, times, and atmospheres. 7. Pellet Density - provide.the mean imersionsand geometric densities including standard deviations, sampling procedures, and minimum densities. If available, provide this infornation for irradiated fuel. S. Pellet Chemical Properties - provide the 0/M ratios, inpurities (metallic r.nd non-cetallic) and specifications for the sintered pellets. 9. Pelict Micrcstructure - provide the average grain sites and grain size distributions, pore merphology and location, axial and radial distributiens of grain size and porosity in the fuel pellets (if net unifer.). Provide sc ple. photo-nicrographs of typical (or atypical) pellets, both before and after irradiation. Show both etched and as-published nicrostructures. 10. Pellet Dimensions - provide statistical distributions, sampling procedures, and ninimum dimensions.
- 11. Provide the methcds of fabrication used te produce the cladding and to '. hat specifications (e.g., chemistry, tensile test, burst, etc.).
Ecw are the rods
- n gected for leaks, hydriding, etc.?
e,.,,e S w .a
- l
.l - d. Describe the types of spaters and holddown springs used.
- 13. Provide any data showing fuel column lengths vs burnup and linear heat
= rating. 14 Provide input data needed b/ 3UCKLE (staff code) for cladding collapse calculations: t' a. Cladding temperature. 'o. Fast Neutron Flux on Cladding. c. Yield Strength, Poisons ratic, and Young's modulus for conditions a 5 b above. d. External pressure. e. Intc-T.a1 pressure (cold, hot before densification, cold, hot after densification). f. Tne measured ' data' for cladding OD, thickness and initial ovality in-cluding the mean, standard deviation, maximum and minimum values, the sample size and sampling procedure.
- 15. Define the critical collapse ovality. Provide technical justification for using this parameter.
15. Provide detailed calculational method and asst ptions made for: 'm a. hot internal pressure, b. clad wall temperature, and c. fast flux in the cladding.
- 17. Describe the creep law used in CREEUCK together with constants used.
Provide cc. parisons with published and other experimental data. s IS. Provide C'-d5UCK verification with controlled experiment results.
- 19. hhat is the margin of safety for the predicted collapse time?
- 20. A UO, production let size is cc posed of virgin oxide, intemediate product, and reprocessed UO.
Presumably the sintering parameters are. adjusted to alic : for 2 differences in amcunts of these naterials. In general terms, describe-h.. different crounts of these materials mig'.t be expected to influence densifi-caricn of is sintered pellets. Describe any plans to folicw the densific.ticn ochavior cf pellets as a it:.cticn of batch composition (i.e., i virgin c:nde, i, reprecessed, etc.).
- 21. Cnc lot of poder apparently had a bulk density which was somewhat different than the densities of other lots. Explain what accounts for this difference.
Provide subsec,uenc information on the relative sintered density of pellets pre-r.ared frcr these lots. Q l l D D . d"h l . i s g-e 1
- t 22. Present a detailed description of your gap conductance and fuel temperature calculation technic,ue. Include a description of all models used such as j thermal expansion, fission gas release, fuel / gas therr.a1 conductivity, fuel welling,' clad creepdo.m, restructuring, sorbed gas, and interfacial pressure. Give references for all models used.
- 23. Using the model described. in Rec,uest No.1, compare calculated gap conductances p
and/or fuel temperatures with experimental data in the same range of parameters as the fuel of interest. In particular, provide results for the specific experimental data given in Attachment 1 (enclosed). 24. Present calculations of gap conductance and fuel temperatures as a, function of time and burnup. Resolve the gap eqnductance into ccmponents for contributions through the gas, solid-solid contact and radiation. Also present hot' gap size, fuel pellet diameter, conductivity of gas mixture, and temperature jump distances (if used) as a function of time. 25. Provide input data needed by GAPCON for gap conductance calculation. a. diameter of pellet b. ID and OD of clad c. enrichment of fuel d. density of fuel (i, theoretical) e. plenum volume f. active fuel column length g, sorbed gas content (cc/ gram fuel) h. surface roughnesses of clad and fuel i. coolant temperature and pressure j. film coefficient between cladding and coolant k. initial-fill gas pressure and compositian 26. If any credit is taken for partial contact of fuel and cladding before complete gap closure, justify this assumption and the particular model used. I 27. Provide the missing Figure 2.2 of report GU-5293 showing the beveled end d i surface configuration. I
- 15. The axial thermal expansion of a, fuel colu~n with a peak power of 15.5 :s/ft is F
give. as 1.044 inches. Shac hm. this nut er is obtaincd. J ]
- 29.. GiMC interprets its autoclave test reruits to mean that pellet e-clad inter-actions are reduced by beveling the pellets. Were the beveled and non-beveled
= pellets exactly alike in fabrication history, density, microstructure, etc.? 1 If available, provide exa~ples'of the microstructures. i i I
q ... 30, Of'the :ircaloy clad rods that were cycled frcm room temperature to 750*F in an autoclave, how many rods were measured for length changes?
- 31. On page 2-2 of report GU-5293, it was reported that diameter measurements
~ ' disclosed no measurable clad creepdown or clad ovalization. Describe the measurements' made; include the nt=ber of rods, the positions along the rods and type of rod (interior or exterior rods). Provide the mean values, standard deviations, and minimum / maximum values. t
- 32. Provide a calculation of the maxir:um axial compressive stresses in a fuel pellet column during full power operation.
Include in this calculation the pellet-to-pellet contact areas and the compressive loads (spring and pelleg weights.) assu.ed. + '33. In section 2.2 of report GU-3293, results of Yankee Rcwe surveillance are described. In this respect provide the following: For the Yankee Rowe and Connecticut Yankee qualification assemblies, pro-a. vide the nicerical results of the diameter measurements versus length. Compare these measurements with your calculation methods. 'b. Describe any differences in-the design and fabrication of the 95 "special surveillance" fuel rods which were inserted i# Yankee Rowe in April 1972 from " normal" fuel rods; e.g., the Batch 6 or 7 rods (other than the beveled surfaces on the pellets). Provide the linear heat ratings and burnups of the rods rencved for c. inspection from Yankee Rowe in September,1972 and February,1973.
- 34. Since there is scme uncertainty that out-of-pile measurements on axial gap size and gap distribution are representative of inpile conditions; please perform sensitivit'f calculations including the case where the maximum theoretical axial gap size is calculated from the nominal initial density and an assumed final density of 96.5% of theoretical using'the assumptions of the AEC model.
An appropriate increase in the maximum gap size must be made to accotmt for irradiation induced growth of the fuel rod cladding. 35. GU-5293 indicates that a pellet with an initially low density (two sigma) will produce 14 less power. Justify this assumption.
- 36. How is the void volume due to pellet dishing included in EOTROD calculaticas?
- 37. For comparison of HOTROD with experimental data, give the identificction numbers of the rods for which the ccmparisons were made.
3S. Explain the method used by HOTROD to model flux distributicn axially along a fuel rod. i i
- 35.. Cf gas released frcr the fuel in HOTROD, what is the assumed cc= position ?
- cth scrbed gas and fission gas)?
- 40. Eglain the restructuring model used by HOTROD.
41. Eglain the cladding creepdown model used by HOTRCD. 42. P cvide a comparisen of the gas mixture thermal conductivity model with experimental data (or a reference which contains this comparison). 43. Provide the variation of internal pressure of Dresden-1, Cycle IX rods with time. .c 4*. Discuss the model used in HOTROD fo? fuel melting if such a = del exists, i.e., heat of fusion, volumetric expansion and melting temperature. 45.
- n those rods which contain Gd90, describe the effect of Gd,C3 addition on 3
telting point, themal conductivity, themal expansion, sintBrability, fuel densification behavior, cladding compataoility, and microstructure. 46. Gd,0 is reported to be hygroscopic. If water is used as a coolant during 3 gE.cing, does the sintered product pick up signif'icant h 0? Has this been 2 dete mined as a function of temperature? Specify method and temperatures used for H 0 detemination. 3 47. Provide details of UO2 - Gd 023 fuel preparation including: a. Type of Gd 02 3 power particle size distribution, specific surface, impurity level, etc. b. Process for powder blending, Homogeneity - degree and how detemined; ion throughout plant. c. d. Methods used to prevent Gd 02 3 contaminat 4S. Does CO2 - Gd 023 have a different tendency to crack during reactor startup than UO ? 2 49. Dascribe any tests or evaluations in or out-of-pile now in progress or con-templated for UO2 - Gd 0,- fuel. 2
- f different frca the model for UO, provide specific values for swelling and 3C.
2 gas release codels for UO2 - Gd 02 3 as a functicn of burnup. 51. Lewis (Nuclear Applications, Vol. 2) is cited as a source of the experi ental cata points used as a comparison with the GUNFC fission gas release ncdel. Er31ain what data from Lewis was used and how the calculations were done for th'e comparison. Give an example of the calculation for one data point. 52. provide E0 TROD fission gas release fractions for the experi ental data provided i, Attachment 2 (enclosed). 5 s .-4 _4 a
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r ATTAGOET 1 Esclosed is experimental data needed to perform gap conductance calculations. Please ca"culate gap conductance, taximun fuel tenpercture and volunetric .svarage fue' temperature over the range of conditions specified. WCAP 2923 WCAP 2923 }G.I. RCD l 2^..A CAPSULE l' -CAPSULE 2 AEG ^ I Pellet ID (inch) .068 ~ .068 0. Pelict OD (inch) 1.25 1.25- .4800 Clad ID (inch) 1.2745 1.2745 .5050 ~' Clad CD-(inch) 1.3245 1.3245 .5650 Pellet Enrich =ent (w/o) .64 .82 2.50 Fellet Density (% TD) 95% - 95% 95% Surbed Gts Cc.nent cc/gm (STP) .01,'.02, i .01,.03, .01,.03, .05N 05N i G5N 2 i 2 l 2 i Clad Mcterici SS348 i SS348 SS Plenu Vcluse in .5 .5 .5 l l Ccolant Ten? 'F 270 270 590 Ceolant Press (psi) 50, 50 1050 Active Fuel Length (inch) 4.41 4.46 30.0 -6 -6 -6 Surface Ecughness, fuel 70x10 70x10 39x10 -6 1 -6 -6 clad'(inch) 70x10 70x10 20x10 i Initi:1 Pi"1. 0:s (psi) 14.7 He f 14.7 He 14.7 Ec .I ?cuer Ren;a C:r/ft) 16-23 2-25 10-22 i l 1.00 1.5 i Peck / Avg. A:cial Flux Ratio 1.00 i i I e
4 - 'AT"AOBST 2 CVTR RODS (Reference WCAP-3850-5)_ IN?UT DATA FOR FISSION GAS CALCULATION _ = ROD 44.732 ROD W13.831-20D 83.632 ROD 502-2-31 F/JJ2'ITIR 4.7 3.8 3.8 2. 4 Enrich Ant (w/o U235)'. Density- (% TD) 93 93 93 93 f' I . Fuel CD (inch) .4317 .4329 .4475 .4300 .4300 - Clad ID (inch)' .4395 .'4395 .4535 ~ -+j Clad '.!all (inch) .024 .024 .017 l .026 1 7.8 6.6 6.0 6.0 Cold Cap' (mils) I t Zr Zr Zr Zr Clad Material Sorbed gas (cc/gm) O. ,O. O. ' l 0. 2 t 1 ata He 1 atm He 1 att He l 1 atm He j initial Fill Gas 80.25 i 81.16 95.12-Active Length (in) 77.81 i i 8 9910 8790 8790 8790 (Stu/hr f:2 *F) l h,,, m 7900 6410 7330 10800 Eurr.up (MWDh:TU) D0 D0 'D 0 D0 2 i . Coolant 2 3 2 1 ' 1500 1 50 Coelant Press (psi) 1500 + 50 1500 1 50 11500 + 50 l l ~.. Ccolant Tenp (Sab)( F) 600 + 10 600 + 10 600 + 10 600 + 10 Fission Gas released 28.6 12.6 4.4 1% I (Za + Kr) (%) 21.8 15.9 17.6 9.3 ../f l me-7.4 ,( c I ,,.,-v- --,,+w. r, a --,w --,,,-,------w- --c, ene,n-e-n -}}