ML20053E797
| ML20053E797 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 06/01/1982 |
| From: | Tauber H DETROIT EDISON CO. |
| To: | Kintner L Office of Nuclear Reactor Regulation |
| References | |
| EF2-57-802, NUDOCS 8206100101 | |
| Download: ML20053E797 (2) | |
Text
H rry Teuber
$r$eSng and Constructdn Detroll Edison Et!GF'>>-
June-1, 1982 EF2 - 57,802 Mr. L. L. Kintner U. S. Nuclear Regulatory Commission Office of Nuclear Reactor hegulation Division of Licensing Washington, D. C. 20555
Dear Mr. Kintner:
References:
(1)
Enrico Fermi Atomic Power Plant, Unit 2 NRC Docket No. 50-341 (2)
Telex, L. L. Kintner to L. E.
Schuerman, April 6, 1982 (3)
Letter, E. Lusis to L. L. Kintner, January 20, 1981, EF2-56,328
Subject:
Redesign of Control Rod Drive (CRD)
Penetration in Biological Shield This letter confirms the verbal information provided during the telephone conversations of March 4, 1982 and March 24, 1982 between you and Mr. W. Street on the above subject, at your request.
1.
The original structural design of the Biological Shield considered the area around the CRD lines to be one large penetration, and the reinforcing steel was designed and placed accordingly. Thus, no reinforcing steel was cut when the concrete in this area was removed, and the replacement blocks that are now being used to fill this opening are not required to support any load other than their own weight.
i 2.
The thermal transient described in Reference 2 con-sists of a 540*F water flowing for a short period l-of time, with subsequent natural cooling.
A heat O g)O f transfer calculation shows that the maximum concrets temperature would be 135 F.
This is less Q
than allowed by the ASME code sections listed in i
the Reference 2 letter as well as that allowed for embedded pipe in ACI 318 (structural concrete code).
l-8206100101 820601 t
PDR ADOCK 05000341 i
A PDR
. =_ - --.
o Mr. L. L. Ki'n tner -
June 1,
1982 EF2 - 57,802 i
Page 2 i
)
3 A second transient (maximum continuous valve leakage).was identified as resulting in poten-i tially higher concrete temperatures.
Conservative calculations indicate local concrete temperatures could be as high as 410*F.
Since the concrete blocks are unrestrained, there would be no large thermal stresses and, therefore, no structural damage.
Several textbooks, Portland Cement Association, American Concrete Institute, Concrete Reinforcing Steel Institute, and professional papers report concrete damage starts to occur from 800*F to 1200*F.
Because these values are far
{
above our. temperature of 410 *F, we expect no spalling or surface damage that would produce i
debris that would interefere with the thermal-expansion of the CRD lines.
Sincerely, i
e--
l r
l cc:-
B. Little 1
)
I i
l t
(
i i
s a
g,,--,-e-y w-
--+,w w,-
, - -, - ~. -
g~,----
,e,
~r
,r,-
,-r ew--w+
,,,v-,
wen
-m.
---n,wr w'-w
~v
-wwe w
v-
--nr,
+e
+,
w,>
e n-w>me-
>, - n -