ML20248K102
| ML20248K102 | |
| Person / Time | |
|---|---|
| Site: | 07000920 |
| Issue date: | 03/09/1989 |
| From: | Harris D RENSSELAER POLYTECHNIC INSTITUTE, TROY, NY |
| To: | Pennington W NRC |
| References | |
| 25397, NUDOCS 8904170225 | |
| Download: ML20248K102 (3) | |
Text
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- c USNRC Departrnent of Nuclear Engineering & Engine l'hnPR C6 Jggg 0
March 9, 1989 NMS3 d
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Mr. W.
Scott Pennington.
P Uranlum Fuei SectIon United States Nuclear Regulatory Commission 7
APRQ51ggg)~d US Department of Energy U.S. NUCLEAR REGULATOR Washington 25, DC to ut son p
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Reference:
1.
Letter R.M.
Ryan to W.
Scott PenningtIn, February.22, 1989.
2.
D.R.
Harris to H.R.
Denton, USNRC,
~" Proposal for HEU/ LEU Core Conversion Pursuant to
-l 10CFR50.64", October 3, 1986.
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Subject:
-CritIca1ity Predictions.
Dear Gir:
It was noted in Reference 1 that the 64 SPERT fuel pins In 8x8 array with pitch'O_.640 inches (1.6256 cm) in the FAFFA will be very_subcritical under all conditions, i
CaIcuIatIons of the muItIpIIcatIon factor have beel.
I carried out using.the LEOPARD-DIFXYRZ methodology described j
in Reference 2.
This methodology was used in designing the i
fuel vault at the RPI Reactor Crltical Facility (RCF) and was-approved by the USNRC for the required criticality caleuIations.
l The worst condition is taken to be if the FAFFA is i
submerged in infinite water at 20 degrees Celslus; for this case the offective_mcItIpIIcatlon factor (keff ) Is calculated to be 0.6838.
This value is far less than the j
-acceptable 0.95.
Tns calculation replaced the steel structure of the FAFFA by water; Introducing the steel structure would reduce k eff.
The calculation used the 36 inch (91.44 cm) active' length of_the fuel and an estimated reflector savings of 7 cm at each end.
If, alternatively, m
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It is assumed that the fuel pins are infinitely long then the calculated k eff is 0.6968, still far less than O.95.
If the infinite water reflector is replaced by a reflector of water and lead or water and steel then the calculated k decreases.
Very tr ly yours,
./Lw Don Id Harris, Director RPl Reactor Critical Facility DRH: JJd cc:
R.C.
Block R.M.
Ryan F.
Rodriguez-Vera R.
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