ML19319B482
| ML19319B482 | |
| Person / Time | |
|---|---|
| Site: | North Anna, Davis Besse  |
| Issue date: | 09/08/1977 |
| From: | Stolz J Office of Nuclear Reactor Regulation |
| To: | Roe L TOLEDO EDISON CO. |
| References | |
| NUDOCS 8001220892 | |
| Download: ML19319B482 (3) | |
Text
-
..-...--.--..7
~
I D
D Dist. bution I
gC Docket File,,
r NRC PDR gr n g'n Q h
Local PDR yh J hl L33 LWR 1 File gb i
D, B. Vassallo v
otP o 577 F. J. Williams J. Stolz Docket No. 50-346 E. Hy1 ton ELD H. Smith Toledo Edison Company D. Crutchfield ATT4:
!!r. Lowell E. Rce Vice President, Facilities bcc:
J. R. Buchanan, NSIC Development T. B. Abernathy, TIC Edison Plaza ACRS (16) 300 Madison Avenue Toledo, Chlo 43ti52 Gentlemen:
RE: FRACTUPE TOUGitlESS AND POTEkIIAL FOR LAPELLAR TEARING OF STEM GEt:ERATC9 AnD RCACTOR COOLANT PU!tP SUMRT HATERIALS During the course of the licensing action for Nortn Anna Power Station Unit Ros. I and 2, a r;un cr of r:cestions were rcised as to the potentialfor lapella ind reactor coolant pu,:p supncrt materials for that plant. Two cifferent steel srecifications (ASTN A3n-7ca and AST;1 A572-70a) covered most of tre P.aterial used for tiese supnorts. Toughness tests, not originally speci-ff ed ar.d not ire the relevant ASTM specificatf oras, were made on those
.Nats for which excess caterial es available. The toughness of tna A36 steel was formd to be adequate, but the toughness of tne A572 steel was relatively poor at an operating temperature of 80 F.
In this case, the applicant has agreed to raise the temperature of the ASTM A572 Deans ir the steam generator supports to a icinimun temperature of 225 F prior to reactor coolant system pressurization to levels above 1000 osig. Auxii-iary electrical heat will be employed to supplement the heat derived from the reacter coolant loop as necessary to obtain the reouired operating teaperature of the structures.
1/ Lamellar tearino.is s' cracking phenomenon which occurs beneath velds and is principally found in rolled steel plate fabrications. The tearing always lies' within the parent plate, often outside the
~
transformed (visible) heat-affected zone DiAZ), and is generally parallel to the weld fusion boundary. Lamellar tearing occurs at certain critical joints usually within large welded structures involving a high degre> of stiffness and restraint. Restraint may gq be defined as a restriction of the movement of the various joint fa components that would normally occur as a result of expansion and ~_
W contractton or weld metal and adjacent regions during welding.
l orrece >
(*1 - -Ilap [ ear' ins la Ms} rtad Wal Fahinjrat4am'; The umitt{nn Institute).
Wb 4 '/
^2
~. "
s
~
NRC PORM 318 (9 76) NRCM 0246
. " k us e. oovesmash reswine'orpics. sets-sename n
s
.w. m L.....
- s. ~~. uw.:
.n:..msx v:n. s:n.~.
8 0 01 2 2 0 h, j
[
mmm n
0 0J.
y n
- s y
?
T
~ Q ~ }[
O h
-L[
U SEP B 1977 Toledo, Edison Company L
Since similar naterials and designs have been used on other nuclear plants, the concerns raised on the supports for the North Anna plant may be applicable for other operating PWR plants.
It is therefore necessary to reassess the fracture toughness and potential for lamellar tearing of the stean generator and reactor coolant pt, tap support materials for all operating PWR plants.
We will equire certain information to make the necessary reassessment of the steaa generator and reactor coolant pump support materials for your plant; tt.arefore, please provide the following information within sixty (60) days after receipt of this letter:
1.
Provide engineering drawings of the steam generator and reactor coolant pump supports sufficient to show the geometry of all principal elenents. Provide a listing of materials of construction.
2.
Specify the detailed design leads used in tne analysis and design of the supports. For each loadino connition (normal, upset, energency and faultea), provice the calculated naxinua stress in each principal ele-cent of the support systen and the corresponding allowable stresses.
3.
Describe how all heavy section intersecting nenber welaments were designed to mininize restraint and lar.ellar tearing. Specify the actual section thicknesses in the structure and provide details of typical joint designs. State the maximum design stress used for the through-tnickness direction of plates and elenents of rolled shapes.
4 Specify the minicum operating temperature for the supports and descriDe the extent to which material temperatures have been me3sured at various points on the supports curing the cperation of the plant.
5.
Spect fy all the materials used in the sucports and the extent to which mill certificato data are available. Descri::e any supple-ental reautremer.us such as melting practicc, toughness tests and tnrough-thickness tests specified. Provide the results of all tests that may better define the properties of the materials used.
6.
Describe the welding procedures and any special welding process rer;uirer?ents that were specified to minimize residual stress, weld and heat affected zone cracking and lamellar tearing of the base metal.
l orric s >
'suassaas a >
oms
- NRC PORM 318 (9-76) NRCM 0240 W u. s. eavsn.rusw en,wwe orricas non-mes
_..~.m.
.. v-
_m
~
=
c Toledc' Edison Cocpany SEP 8 1977 7.
Describe all inspections and non-destructive tests that were oorfomed on the supports during their fabrication and installation, as well as any additional inspections that were perfomed during the life of the facility.
In addition to the information requested above, please provide your cwn evaluation of the fracture toughness of the steam generator and reactor coolant pwp support materials for your plant. P1 ease inform us within thirty (30) days after receipt of this letter of your schedule for pro-viding us with your evaluation. This generic reouest was accroved by GAO, 2-180225 (RC072), clearance expires July 31, 1980. Approval was given under a blanket clearance specifically for identifieo generic problems.
Sincerely,
~.
Original s!"nc3 by J. Anger [
q
-dohn F. Stolz, Chief j
Light Water Reactors Branch Ho.1 Divisio(of Project Panagemnt A...
cc: Mr. Ocnald H. Hauser, Esq.
The Cleveland Electric Illuainating Company P. O. Box 5000 Cleveland, Chio 44101 rarald Charnoff, Esq.
Shaw, P1 ttNn, Potts a'id Trowbridge 1800 M Street, H. W.
Washing ton, D. C.
20036 Leslie Henry, Esq.,
Fuller, Sency, Henry and Hodge 300 Madison Avenue Toledo, Ohio 43604 D
D oo J l '-
LWR 1 d pl,WRJ g o,
- c.,
LEnglsky/jfJ3polz 9/ft /77 (f 9/6/77 1
NRC POEM 318 e 9-74) NRQi 0240
. W u. e. eavsawesem ememne orrics.en-ene.eae
..: ?
. ~.
.-y.-
.c...
1