ML20108E123
| ML20108E123 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 12/06/1984 |
| From: | Gucwa L GEORGIA POWER CO. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20108E124 | List: |
| References | |
| IEB-80-13, NED-84-597, NID-84-597, TAC-55236, TAC-59539, NUDOCS 8412140212 | |
| Download: ML20108E123 (3) | |
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- E Georg a Power company,
' 333 Piedmont Avenue Atfanta. Georgra 30308.
Telephone 404 5266526 Mailing Address:
. Post office Box 4545
. Atlanta.Georgta 30302 Georgia Pbwer L. T. Gucwa.
the southern e@ctnc system Manager Nuclear Engineenng and Chiel Nuclear Engineer NED-84-597 Decenber 6,1984 Director of Nuclear Reactor Regulation i
Attention: Mr. John F. Stolz, Chief Operating Reactors Branch No'. 4 Division of Licensing U. S. Nuclear Regulatory Counission
{
Washington, D..C.
20555 NRC DOCKET 50-321 OPERATING LIONSE DPR-57 EDWIN I. HA'ICH NUCEAR PUWP UNIT 1 l
00RE SPRAY SPARGER CRACKING Gentlemen:
i
' Pursuant to the requirenents of I&E Bulletin 80-13, " Cracking in Core Spray Spargers",
Georgia Power Company (GPC) submits herein the justification for continued operation of Plant Hatch Unit 1 with a cracked core spray. sparger.
This subnittal docunents the presentation made to the NRC staff on Novenber.15,1984, in Bethesda, MD.-
Visual inspection revealed the presence of = the crack on the lower sparger arm near the 3500 T-box.
'Ihe circumferential crack is located in the heat-affected zone of. the sparger to T-box weld, approximately 1/8 inch '
fran the weld.. It spans at least 1800' of pipe circumference and is a maximun of 0.010 inch wide.
'Ihe attached report, NEDO-30825, " Core fpray Sparger Crack Analysis for L
Edwin I. Hatch Nuclear Power Station Unit 1" provides the justification for
~ continued safe operation with the - crack.
'Ihe analysis denonstrates that even 'if a 3600 circurferential through-wall' crack is postulated, the sparger would renain intact, no safety concern would be creau J by loose parts, and the cooling function of ' the core spray systen would not be
. degraded.
h2ggk2 0
jpot Yl
h TGeorgiaPowerb
- Director of Nuclear Reactor Regulation Attention: Mr. John.F. Stolz, Chief 4
Operating Reactors Branch No.~4 e
Deceber 6,1984 Page 2 For added margin,'GPC has. elected to install a clamping device to ' limit
- relative movenent of the two sections of the sparger-even if the-crack were to propogate 3600 through-wall.
We design and function of the clamp 1
assembly are similar to those of clanps installed. at. other operating ENRs.
W e clap can be characterized as a "C-clm p" device which grips the sparger
'with a pair of fingers on each side of the T-box.
%e clamping - force is provided by 'two pairs. of 3/4-inch bolts which are. torqued and locked in place with a proven crimping technique.. Lateral movement of the clanp is prevented' by the sparger nozzles._ ne clanp assembly is fabricated frca-type 304L austenitic stainless steel with a maxistan carbon content of 0.02
-weight-percent. % is material has been denonstrated to have good resistance i
ito intergranular stress corrosion cracking in the BWR envirorynent.
%e clamp is a passive device which provides added structural margin.to the core spray sparger without -interfering with its BOCS. function.
Se clanp is single failure-proof in that only two bolts are required for.-it to perfonn Jits function.
A stress analysis. shows that the clamp, although
'non-code, meets.the stress requirenents of A91E Section III, Subsection NG.
he' clamp is designed to ensure that it will not becae loose during a Lcore. spray injection thermal transient; however, the potential consequences of-loose parts are adeIuately bounded by the analysis contained 'in 3
l NEDO-30825.
It has been concluded by the _ Plant Review board and the Safety Review i '
. Board that. continued operation of Plant Hatch, Unit.1 would not involve an
~
.unreviewed safety' question under :10 CPR 50.59 because:
.l.
.%e probability of occurrence or the consequences of an accident or i
malfunction of sluipnent important to safety are not increased
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above those analyzed in the FSAR.since neither the crack nor the clamp interferes with the function of.the core spray systen.
f 2.
We possibility of an accident or malfunction of a different type l
than any analyzed in the FSAR is not created.
3.
%e margin of safety of the core spray sparger as defined in the.
'~
basis for any Technical Specification is not reduced because its structural integrity is not ccampromised by the presence of the
[
' crack or the clamp.
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nons
Georgia Power d Director of Nuclear Reactor Regulation Attention:. Mr. John F. Stolz, Gief Operating Reactors Branch No. 4 December 6, 1984 Page 3 This subnittal canpletes the reporting requirenents - of I&E Bulletin-80-13 for the current refueling outage.
Please contact this office if you rq uire any further information.
Yours truly, N&cm L. T. Gucwa JH/blm Enclosure xc:
(w/ encl.)
J. T. Beckhan, Jr.
H. C. Nix, Jr.
J. P. O'Reilly (NRC-Region II)
Senior Resident Inspector NRC Office of Inspection and Enforcenent Division of Reactor Operations Inspection (Washington) j imns