ML20081B663
| ML20081B663 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 03/06/1984 |
| From: | Dixon O SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8403090271 | |
| Download: ML20081B663 (3) | |
Text
_
.O SOUTH CAROLINA ELECTRIC & GAS COMPANY post oprica 7e4 CotuusiA. SOUTH CANOLINA 29218 O. W. DiMON, JR.
vie. ca..
ar March-6, 1984 PdWCLSAa OP. RAT @N.
f Mrs Harold'R. Denton, Director Office of' Nuclear Reactor Regulation
.'O.S.
Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
Virgil C.
Summer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 High Density Spent Fuel Storage Racks
Dear Mr. Denton:
.In discussions with the NRC staff on February 17, 1984, South Carolina Electric & Gas Company (SCE&G) was asked to provide additional information concerning the Licensing Report on High Density Spent Fuel Racks for the Virgil C. Summer Nuclear Station.
The.following explanations are provided in respone to NRC questions.
The first question states that it is not apparent from the
-report that the area surrounding the Boraflex is vented, and rMuests an explanation of how this area is vented.
Figure 3.3 (attached) shows where the neutron absorber plate is located.
As shown in Figure 3.4B of the report, the top j
' spacer'is. located above the top end of the poison plate.
The
~
width of ' the poison material and - the top spacer is smaller than the width of the annulus.
As a result,-there are vent openings in the corners as shown in Figure 3.3.
An isometric drawing'will be'available at the scheduled meeting with the NRC on March 13, 1984 to further clarify any questions about iventing.
The.second question concerns the existence of horizontal spacers around the Boraflex.
There are no horizontal spacers
^
to center the poison material in the cell.
The manuf acturing i
process locates and compresses'the Boraflex sheet in a
- symmetrical manner.
Any lateral misalignment of poison has a negligible effect on the subcriticality level.
' 3DnaDocv.osooop*g p\\
e403o9o271 e40 m h
4 o
Mr. Harold R.
Denton High Density Spent Fuel Storage Racks March 6, 1984
- The third _ question concerns confirmation of the wall thickness of the inner cell.
The inner cell wall is.049 inches thick, and the outer cell wall is.065 inches thick as noted on page 4-10 of the report.
The fourth question concerns the potential for support leg galling.
The material composing the female part of the support leg is ASTM 479-S21800 (Armco Nitronic 60), and the male part is composed of SA 564-630 (17-4Ph) age hardened at 1050*F.
This combination of materials is highly resistant to galling, and provides desirable material properties for boric acid environments.
The fifth question was.in the form of a recommendation to have
~
two strings of surveillance capsules per poisoned region.
It recommended that one string be placed adjacent to the most recently discharged element and the other string be placed adjacent to the first element permanently loaded into the new racks.
It was further recommended that samples be examined from each string at every examination interval.
The poison surveillance program will be modified to accommodate these recommmendations.
If there are any further questions, please contact us.
Very truly yours, 6-O. W.
Dixo, Jr.
AM:OWD/gj
Attachment:
cc:
V. C.
Summer C.
A. Price T.
C. Nichols, Jr./O. W.
Dixon, Jr.
C.
L. Ligon (NSRC)
E.
H. Crews, Jr.
K. E. Nodland E. C.. Roberts R. A. Stough
{
W. A. Williams, Jr.
G.
Percival D. A. Nauman C. W. Hehl J. P.
O'Reilly J. B..Knotts, Jr.
Group Managers NPCF O.
S.
Bradham File I
i
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