ML19270F040
| ML19270F040 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 01/18/1979 |
| From: | Speis T Office of Nuclear Reactor Regulation |
| To: | Justin Fuller PUBLIC SERVICE CO. OF COLORADO |
| References | |
| NUDOCS 7901250070 | |
| Download: ML19270F040 (3) | |
Text
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JAN 181975 Central File JCarter ARB R/F GMadsen, IE POR /
DF 50-267 RMattson JKnight VStello spawjicki RBoyd/ Dross RBosnak Public Service Company of Colorado WGammill FSchauer ftr. J. K. Fuller, Vice Frosident RTedesco RSchamberger Engineering and Planning TSpeis RWoodruff P. O. Box 361 RIreland CTan Platteville, Colcrado 3C651 PCheck FLitton GKuzmyc SUSJECT:
SURVEILLA'tCE PROGRAli FOP, PG7. GRAPHITE In order to continue car review cf 'the sur/eillance plan for Type PG7.
grapnite we will recuire the enclosed information in addition to that provided with your letter of October 26, 1972.
As we stated in our letter of June 5, 1973 it will be necessary for you to make a formal applicat4on to load the surveillance test ele".ents in the reactor.
This application should te made promptly in view of Fort St. Vrain's anticipated shut down date for fuel reloading of Itarch 1,1970.
Sincerely.
Original S!. neif li>
Themis P. 5;.e s Themis P. Speis, Chief Advanced Reactors Oranen Division of Project !!anagement cc:
Bryant O'Donnell, Esquire Ke'ly, Stansfield 10'Donnell 990 Public Service Ccapany Building Denver, Colorado 80201 James D. Graham D b llanager, Licensing and Regulation D
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7901250070
REQUEST FOR ADDITIONAL INFORMATION PSCo RESPONSES TO NRC LETTER OF JUNE 6, 1978 W. P. GAfEILL TO J. K. FULLER, " GRAPHITE SURVEILLANCE PROGRAM" Response No. 1 When will laboratory data be available on oxidized PGX mechanical properties?
Response No. 2 Discuss the feasibility of inserting test specimens at the second refueling that would be capable of mechanical testing following irradiation.
Response No. 6 Provide or reference data illustrating the 40 percent deviation in weight loss and oxidation depth obtained for PGX graphite.
Response No. 9 1.
The mass transport coefficient within the graphite, D', is seen to be dependent on D Since D' is not defined here, is D' really D eff., as def tbe.d on page 22?
2.
Provide a reference or a description of the DOE funded, high pressure test rig and planned experimental program.
This des-cription should depict in detail how the effectsof such variables as temperature, pressure, specimen size, flow rate and oxidant concentration will be determined.
3.
What is the justification for using the Langmuir-Henshelwood equation ? What are the constants to be used and how well are they known? This equation does not appear to consider explicitly catalytic action.
Response No. lla In your discussion of the theoretical basis for graphite oxidation a quantity "m" is used to relate the gas diffusion coefficient D,2 to l
the in-pore diffusion coefficient D eff.
It is stated that "m" is a geometry parameter related to porosity and tortuosity of the graphite.
A relationship for "m" is given by Equation (2) but this appears to be a restatement of definitions for L. Deff, and Kv given above.
If the formalism presented is to be considered then it is necessary to describe
"m" by independent theory or at least provide empirical values from experiments. Without such a description it does not appear possible to make such conclusions that the diffusion length L within the graphite body is proportional to the square root of the system pressure.
In fact, it is possible that L could be independent of pressure as would be the case for Knudsen type diffusion where porosity effects would be controlling. Please provide a response to the above statement including a discussion of the potentials for Knudsen diffusion, Response No.11 b The description of the core support structure should be expanded to include dimensions of the core support blocks and other features of the core support structure shown in Figure 1 (e.g., key dimensions, graphite webs, core support floor thickness).
Response No. 12 a 1.
The plant condition for the thermal stress analysis is taken at 100 percent power at normal operation.
Demonstrate that this condition encompasses other possible plant conditions which conceivably could cause a greater thermal stress.
For example, consider temperature distributions during such transients as are permitted by the Technical Specifications, Figure 3.1-1, or might be encountered by core cooling following a design basis depressurization accident or a restart condition following a temporary loss-of-forced circulation.
2.
Provide a reference for the PGX mechanical properties presented in Table I.
How do these properties change with irradiation? Have these changes been accounted for in the analysis?
3.
What information can be provided supporting the validity of the computer ccdes used to calculate the stresses in the core support block?
4.
Give a physical explanation for the stress concentrations shown on page 65.