ML20064E537
| ML20064E537 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 11/15/1978 |
| From: | Finfrock I JERSEY CENTRAL POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20064E536 | List: |
| References | |
| NUDOCS 7811200164 | |
| Download: ML20064E537 (48) | |
Text
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9 JERSEY CENTRAL POWER 6 LIGHT COMPANY l r
OYSTER CREEK NUCLEAR GENERATING STATION Provisional Operating License No. DPR-16 Technical Specification Change Request No. 68 Docket No. 50-219 Applicant submits, by this Technical Specification Change l Request No. 68 to the Oyster Creek Nuclear Generating Station Technical .
Specifications, changing sections 3.4 and 4.3 dealing with the Core !
Spray System.
JERSE ENTRAL POWER 6 LIGHT COMPANY BY 0 {lll4k // p /
Vice P
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STATE OF NEW JERSEY COUNTY OF MORRIS s
Sworn and subscribed to before me this /f2/ day of '7'/Awu.b ,1978.'
DiNkW Notary Public PHYLLIS A. KABIS fl0TARY PUBLIC 0F NEV/ JERSEY
- My Commissian Expires Aug.16,1979 l'
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UNITED STATES OF AMERICA NUCLEAR REGULATORY C05NISSION f
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! IN THE MATTER OF )
, ) DOCKET NO. 50-219 i
JERSEY CENTRAL POWER 6 LIGHT COMPANY )
l 4 i CERTIFICATE OF SERVICE 1
I This is to certify that a copy of Technical Specification Change !
Request No. 68 for the Oyster Creek Nuclear Generating Station Technical :
Specifications, filed with the U.S. Nuclear Regulatory Commission on !
November 15, 1978, has this ISth day of November, 1978, been i served on the Mayor of Lacey Township, Ocean County, New Jersey by deposit in the United States mail addressed as follows:
The Honorable Lawrence J. McNally [
Mayor of Lacey Township
. P.O. Box 475 ,
Forked River, New Jersey 08731 JERSEY CFHTRAL 7 POWER 6 LIGHT COMPANY BY: /Wsf )p VictfPr den i
, ( I
{ DATED: November 15, 1978 {
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Jersey Centr:1 P;wer & Light Comprny
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{'J Madison Avenue at Punch Bowl Road Momstown, New Jersey 07960 (201)455-8200 November 15, 1978 The Honorable Lawrence J. McNally Mayor of Lacey Township P. O. Box 475 Forked River, New Jersey 08731 Jhar Mayor McNally:
Enclosed herewith is one copy of Technical Specification Change Request No. 68 for the Oyster Creek Nuclear Generating Station Technical Specifications.
Titese documents were filed with the U.S. Nuclear Regulatory Commission on November 15, 1978.
Very truly yours, l
- 2/t x- y Ivan R. Fin ock, r.
Vice Presi t
( la Enclosure Jersey Central Power & Light Company rs a Member of the Genera' Puthe ut lities System
. . JERSEY CENTRAL POWER S LIGHT COMPANY OYSTER CREEK NUCLEAR GENERATING STATION PROVISIONAL OPERKTING LICENSE NO. DPR-16 DOCKET NO. 50-219 Applicant hereby requests the Commission to change Appendix A to the License as follows:
- 1. Sections to be changed:
Sections 3.4 and 4.3. .
- 2. Extent of changes:
Inservice inspection of the core spray spargers is being augmented.
Core Spray System 2 is being required to provide 3640 gpm to the reactor.
- 3. Changes requested:
Replace pages 3.4-4, 4.3-S, and 4. 3-8 with the attached pages.
- 4. Discussion:
These changes are being made in response to concerns expressed by the PORC, GORB, and NRC staff upon review of the repair of the crack in the Core Spray System 2 sparger during the 1978 refueling outage.
bacec: Thi : npocification zccm c that ad quat emercency core cooling capability is available . hen the cure :, ray cystem in required.
Ifaned en the locc-of-coo! ant, analycis r. r the uorst line br-ak, a core npray of at least 3h00 Cpm re in.i red sithin 35 second to V accure elTect.ive core cooling.* (ib Thur, i f one loop beccmec in-
$ operabic, the operable loop is e tpuble A providinf, cooling to the 'f core an.1 the reactor may remai1 in oper tien for a period of 7 days provided repaire can be cumpleted uit.hia that time. The 7 days is based upon the consideration discucced in the Lace: of Specification 3.0 and t he pump operability tests of Specificut. ion b.4 If repairs cannot be made, the reactor ic depreccuriced and vented to prevent preccure buildup and no uork ic allowed to be performed on the reaet.or which could result in lowering i he water level below the r.afety limit of 4 '8".
Each core spray loop contains redundant active components. There-fore, with the loss of one of these components the system is still capable of supplying rated flow and the system ac a whole (both loops) can tolerate an additional single failure of one of its active componente and still parform the intended function and pre-
! vent clad melt. '1herefore, if a redundant active component fails, a lander repair period is justified based on the consideration given in the bacca of Specification 3.2. The considerat.ien indicates that for a one out of 4 requirement the time out of service would be T
= 30 day: = 17.5 days 1.71 1.71 Specifiention 3.4.A.9 ensure: that if one diesel is out of cervice
% ,/ for repair, the core spray system loop on the other diesel must be operable with no components out of cervice. This ensures that the loop can perform its intended function, even assuming one of its active components fails. If this condition is not n.et, the reactor is placed in a condition where core spray is no longer required.
When the reactor is in the chutdown or refueling mode and the reactor coolant system is less than 212 0F and vented and no work is being
(. performed that could recult in lowering the water level to less than .
4'8" above the core, the likelihood of a leak or rupture leading to uncoverinC of the core is very low. The only source of energy that must be removed is decay heat and one day after shutdown this heat generation rate in conservatively calculated to be not more than 0. 6 of rated power. Sufficient core spray flow to cool the core can be ,
supplied by one core spray pump or one of the two fire protection nyctem pumps ander these conditionc. When it is necessary to perform repairc on the core cpray system componenta, power supplien or water sources, Specification 3.4.A.7 permite reduced cooling system capabi-lity to that which could provide cufficient core cpriy flow from two independent sourcec. !4anual initiation of thece cyctems is adequate since it can be eacily accomplished within 15 minutes during which time the temperature rise in the reactor will not reach 2200 F.0
- Core Spray System 2 is required to deliver 3640 gpm, V
AmendmenI.I;a. 1 ;' Dril.ed : .lanuary :.'l . DJ/6
. 3-5 v
TAALE 4.3.1 EXAMINATION SCHETill; E OF Hr:ACOR CODI N;T SYSTed Inspection Inspection Process Frequency Component Samole Extent (S ee t<ote 1) (See Note 2) 100% safe and RT & a to pipe weld VT
- 7. Circumferential One 107 of weld RT & a weld head to length includ- VT nead flange ing 2 intersects with longitu-dinal welds
- weld to cap ,
v G. Integrally wel- -
ded internal ves-sel components:
l Core spray One Entire access- VT a piping ihle surfaces
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and welds Core spray One Entire access- VT e sparger ible surfaces and welds Shroud support Part- Any accessible VT a ring tal surface Liquid poison Pa rt- Any accessih]e VT' a sparger tal surface and/or welds
- 10. Cladding on 2 pat- Surface VT a head ches
4.3-8 TABLE 4.3.1 !
EXAMINATION SCHEDULE OF REACTOR COOLANT SYSTEM
(
' NOTES:
VT Examination by viewing l
- 2. a. Inspect same sample twice during first 5 years of operation !
, b. 100% inspect partial sample during at least two inspections !
such that 100% of the studs are inspected during the first
- 5 years of operation.
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- c. Inspect partial sample during at least two inspections such I that 10% of the penetrations are inspected during the first l 5 years of operation
- d. Normal maintenance observations - Examination by viewing, f where accessible, during maintenance
- e. Full inspections of the accessible surfaces and welds of both spargers ,
and the repair assembly on core spray sparger no. 2 shall be carried [
out during each of the next five refueling outages beginning in 1979, !
subsequent inspections will be conducted at 5 year intervals. I
- 3. The examination schedule of Table 4.3.1, extent of examination, ;
( inspection process, and inspection frequency shall be reviewed after i the fourth year of operation and a revised specification for subsequent i inservice inspection developed.
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r Technical Specification Change Request No. 68 Safety Evaluation
, During the 1978 refueling outage a crack was discovered by inservice inspection in the sparger of core spray system 2. The crack and its repair ;
are described.by a Repair Proposal and Safety Evaluation. That information was presented to the NRC staff on November 3, 1978. ,
l The PORC, GORB and NRC staff all agreed that augmented inservice inspection of the core spray spargers and of the repair assembly was desirable. This technical specification change would require that a full visual inspection of all accessible surfaces and welds of both core spray spargers and of the i repair assembly be performed at each of the next five refueling outages, starting in 1979. At the completion of this period of augmented inspection the inspection interval would revert to that existing before the crack was discovered. Other changes,could of course be made depending on the results of the augmented inservice '
inspection.
The safety evaluation of the sparger crack repair also determined that the performance of Core Spray System 2 would not be degraded by the crack (even :
if it should propogate around the pipe and open up to the maximum extent !
permitted by the repair assembly) if .the Core Spray System 2 flow rate to the reac-tor were 3640 gpm rather than the 3400 gpm previously assumed. This technical specification change request would change section 4.4 and the bases to section 3.4 to require that the 3640 gpm be demonstrated during pump operability tests.
Plant procedures for inservice inspection and core spray pump operability testing shall be appropriately modified when this technical specification :
, change has been approved.
i l Since this technical specification change request would serve only to
! 7 increase inservice inspection and to increase core spray pump operability i J i requirements, it in no way reduces the safety of the Oyster Creek Station. It !
does not increase the possibility of any accident or malfunction of equipment nor does it introduce the possibility of any accident or malfunction of equipment not previously analyzed. It does not reduce any margin of safety '
of the plant. It can therefore be concluded that the change presents no :
significant safety considerations.
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4.4. EMERGENCY COOLING Applicability: Applies to surveillance requirements for the emergency cooling systems.
Objective: To verify the operability of the emergency cooling systems.
I Specification: Surveillance of the emergency cooling systems shall be performed as follows:
Item Frequency 1 A. Core Spray System
- 1. Pump Operability once/ month. Also after major maintenance and prior to startup followingarefyelingoutage.
/ 4 Core Spray System 2 shall be demonstrated to be capable of delivering 3700 gpm to the core at a reactor pressure of 110 psi.
- 2. Motor operated valve operability Once/ month
- 3. Automatic actuation test Every 3 months
- 4. Pump compartment water- Once/ week and after each entry tight doors closed -
- 5. Core spray header AP instru-mentation check Once/ day
(~ calibrate Once/3 months
- test Once/3 months B. Automatic Depressurization
- 1. Valve operability Every refueling outage
- 2. Automatic actuation test Every refueling outage C. Containment Cooling System
- 1. Pump operability Once/ month. Also, after major maintenance and prior to startup following a refueling outage.
- 2. Automatic actuation test Every 3 months
- 3. Pump compartment water- Once/ week and after each entry.
tight doors closed
.N J3f y Cefitfel Power & Light Jersey Contral Power
- e. = = = . e .- &LF3ight Company REPAIR PROPOSAL NO. 320-78-1 OYSTER CREEK NUCLEAR GENERATING STATION CORE SPRAY SPARGER NO. 2 l
Prepared by: E. J. Growney J. S. Chardos '
Approved by: ,W_
M 1. Crimmins, g /
Manager, Generation Engin rin l
Title Page Revision No. Date !
T 1 11/1S/78 i
LIST OF EFFECTIVE PA3ES Page No. Revision No. Date T 1 11/15/78 i 1 11/15/78 ii 1 11/15/78 1 1 11/15/78 2 1 11/15/78 3 1 11/15/78 4 1 11/15/78 5 1 11/15/78 6 1 11/15/78 7 1 11/15/78 8 1 11/15/78 9 1 11/15/78 10 1 11/15/78 11- 1 11/15/78 12 1 11/15/78 13 1 11/15/78 14 1 11/15/78 15 1 11/15/78 16 1 11/15/78 17 1 11/15/78 18 1 -
11/15/78 19 1 11/15/78 20 1 11/15/78 21 1 11/15/78 TITLE PAGE l REVISION NO. DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 i 1 11/15/78
TABLE OF CONTENTS
1.0 INTRODUCTION
2.0 BACKGROUND
3.0 REFERENCES
4.0 PROBABLE CAUSE OF CRACK 5.0 EVALUATION OF PRESENT CORE SPRAY SPARGER CONFIGURATION 6.0 PLANNED CORRECTIVE ACTIONS 7.0 SAFETY EVALUATION FIGURES:
Figure 1 -- Reactor Vessel Cross-Section showing Core Spray Piping and Spargers Figure 2 -- Plan View, Upper Core Spray Sparger Figure 3 -- Sketch of the Crack in the Upper Core Spray Sparger--Side View Figure 4 -- Sketch of the Crack in the Upper Core Spray Sparger--Bottom View Figure S -- Cross-Section Characterization of the Crack ATTACHMENTS:
I. Safety Evaluation by J. Knubel dated November 2,1978 II. Core Spray Evaluation dated November 13, 1978 l
l TITLE PAGE REVISION NO. I DATE I Repair Proposal No. 320-78-1 ..
OCNGS Core Spray Sparger No. 2 11 1 11/15/78 i
1.0 INTRODUCTION
Scheduled in-service inspection of reactor it.ternals during the Fall 1978 refueling outage at Oyster Creek identified an isolated linear indication in a portion of one of the two core spray syste= spargers (upper sparger, 4
i.e. , Core Spray System No. 2) inside the reactor vessel. Subsequent visual examinations and tests showed that the indication in the core ;
< spray sparger is a crack which extends at least 2200 of the circumference of the 3-1/2" Schedule 40S sparger and, apparently, penetrates the wall over about 1350 of the circumference.
The purpose of this proposal is to:
- 1. Describe the examinations and tests which characterize the observed ,
crack. l i
- 2. Summarize results of evaluations of the consequences of the crack. i
- 3. Describe the planned corrective actions and surveillance, and i
- 4. Present the Safety Evaluation of the "as repaired" core spray system.
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i TITLE l RAGE REVISION NO. I DATE [
Repair Proposal No. 320-78-1
,OCNGS Core Spray Sparger No. 2 1 1 11/15/78 l
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2.0 BACKGROUND
The Oyster Creek reactor vessel contains two independent core spray spargers which are fed by two separate core spray systems. Each of these systems is provided with fully redundant pumps, valves, power ,
supplies, controls, and instrumentation. Each core spray sparger assembly consists of two 180 0segments of formed 3-1/2" Schedule 40S stainless steel piping, each of which contains 56 spray nozzles (112 nozzles total per assembly). The 180 halves of each sparger assembly are connected at their centers to 5" Schedule 40 inlet piping. h' hen ,
the system is actuated, water from the core spray pumps is directed through a reactor vessel nozzle and a penetration in the core shroud to each half of the core spray sparger assembly. Each 1800 half of the spargers is supported at the location of the 5" inlet pipe ,
connection which is welded to the shroud; and by three, approximately equally spaced support brackets on each side of the central inlet pipe connection. The support brackets consist of 3/8" thick vertical i l
( gusset plates, with 1-1/2" wide bearing pads, which support the sparger arms in the radial and vertical directions. The sparger arms are free to slide in a circumferential direction (relative to.their inlet connection to the shroud) as required to accommodate any differential thermal expansion between the shroud and the spargers during injection of cool core spray water. A cross-section through the reactor vessel at the elevation of interest is shown in Figure 1. A plan view showing TITLE l RAGE REVISON NO. DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 2 1 11/15/78
T 4
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i the upper core spray sparger (designated System No. 2) is presented in Figure 2.
In-service inspections performed during the Fall 1978 outage included l
visual examination of accessible portions of the core spray spargers -
using underwater television viewing and video tapes. These examinations included the accessible portion of the full 3600 of both the upper (System No. 2) and lower (System No.1) spargers, spray no::les, support brackets, and inlet piping connections. The portion of each sparger l f
which were visually examined included the half (from top center to bottom center of the 3-1/2" pipe) which faces the reactor centerline. Accessible portions of the 5" inlet piping between the reactor vessel core spray L
no::les and the OD of the shroud were also examined.
The results of these exaninations (performed during mid-October)-revealed-a single crack-like indication at orientation 2080 (see Figure 2) in the upper sparger. A sketch of the indication is shown in Figure 3. As indicated in this figure the crack approaches near the toe of the nearby ,
no::le fillet weld and extends around the circumference of the sparger at least as far as the top center of the sparger pipe. The crack width :
appears greatest at a point below the "3 o' clock" position and becomes ,
notably finer (tighter) as it approaches the top and bottom of the pipe. i Examinations of the support brackets, spray no::les, and remaining accessible portions of both upper and lower spargers revealed no cracks or ;
TITLE RAGE REVISION NO. I DATE Repair Proposal No. 320-78-1 I OCNGS Core Spray Sparger No. 2 3 1 11/1S/78 4
signs of vibration, fretting, or movement of the spargers relative i to the supports.
Subsequent inspection efforts during the week of October 30, 1978 enabled the plant. staff to view and record a picture of the bottom of the upper i
sparger at the location of the crack. This inspection revealed that the ;
crack does approach near the nozzle fillet weld, follow the weld contour l for a short distance, and then proceeds up the rear wall of the sparger pipe.y.This crack extension was visible for approximately 450 from bottom '
dead center of the sparger up the rear (or outside) of the sparger pipe.
In this area, the crack appears to be as tight as it is at the bottom of the sparger on the inner radius. See Figure 4 for a sketch of this portion of the crack.
In order to further characterize the depth and length of the crack at the 2080 location in the upper sparger, air was introduced into the sparger through an instrument line which is attached to the core spray piping near the core spray no::le. The air was gradually fed into the sparger until bubbles were observed from the spray no::les, indicating that all water was forced out of the sparger. During this process, air bubbles were observed to leak from the crack from near the bottom center of the sparger to a location approximately 45o from the top center of the sparger. No air bubbles were observed from the inaccessible back side of the sparger nearest the shroud inside diameter. This test demonstrated that the crack penetrates the wall of the sparger over an arc length of about 1350 Figure 5 shows a cross-section of the TITLE PAGE REVISION NO. DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 4 1 11/15/78 l
pipe at the crack location with the best estimate of the crack configuration.
No evidence of air leakage was detected from any other location on the sparger. Similar air tests of the lower sparger (System No. 2) were not performed because the spray no::les are located on the top of this sparger.
(NOTE: The television inspection equipment used for the inspection is considered to have very good resolution. At the distances used for these inspections and under the same lighting and medium conditions, the equipment was shown to have a resolution of 400 lines / inch) .
l TITLE PAGE l REVISION NO. DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 5 1 11/15/78
3.0 REFERENCES
3.1 MPR Drswing 1083-12-01, Rev. D. l 3.2 G. M. Gordon, R. E. Blood, " Reactor Structural Materials Environmental Exposure Program" given at Symposium on Materials Performance in Operating Nuclear Systems, CONF-7308801-August 1973, M. S. Wechler and W. H. Smith, Editors, Iowa State U. , Ames, Iowa.
3.3 Jersey Central Power 6 Light Company, Oyster Creek Nuclear Generating Station, Docket No. 50-219, Request for Amendment to Provisional Operating License No. DPR-16, Revision 1, to Technical Specification >
i Change Request No. 49, May 30, 1978.
3.4 Exxon Nuclear Company, Oyster Creek LOCA Analyses Using the ENC !
NJP-BWR ECCS Evaluation Model, XN-NF-77-55, Revision 1, March 1978.
3.5 Exxon Nuclear Company, The Exxon Nuclear Company KREM-Based NJP-BWR ECCS Evaluation Model and Application to the Oyster Creek Plant, XN-75-55, Revision 2, Aagust 1976. l 3.6 Exxon Nuclear Company, Responses to NRC Questions Concerning NJP-BWR
, ECCS Evaluation Model and Application to the Oyster Creek Plant, !
s I XN-75-55, Revision 2, Supplement 1, September 1976. ;
3.7 Exxon Nuclear Company, Supplementary Information Related to the !
Exxon Nuclear Company WREM-Based NJP-BWR ECCS Evaluation Model and '
Application to the Oyster Creek Plant, XN-75-55, Revision 2, December 1976.
3.8 Safety Evaluation Report by the Office of Nuclear Reactor Regulation Regarding Review of the Exxon Nuclear Company Non-Jet Pump Boiling I
Water Reactor ECCS Evaluation Model Described in Exxon Topical r
TITLE RAGE REVISION NO. DATE 1 Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 6 1 11/15/78 e - -
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Reports XN-75-55, Revision 2, dated September 1976, XN-75-55, i Revision 2, Supplement 2, dated December 1976, for Conformance f to Appendix K to 10 CFR 50, USSRC, February 25, 1977. i 3.9 Jersey Central Power 6 Light Company, ECCS Modification Core Spray Electrical Crossconnect, Oys'ter Creek Nuclear Generating Station, Docket 50-219, Attachment II, Revision 1, July 15, 1975. i l-i I
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i TITLE PAGE REVISION NO. I DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 7 1
- 11/15/78 t <
I 4.0 PROBABLE CAUSE OF CRACK The cause of the crack in the upper core spray sparger at orientation 208 has not been positively identified. However, on the basis of the information which is available, the most probable cause of crack initiatio'n and propagation is as follows: ;
i Crack Initiation and Propagation -- According to the GE specification j to which the spargers were manufactured, the spargers were required to be in the solution annealed condition. Cold forming (which apparently was performed) was permitted without subsequent solution anneal provided i the bend radius was not less than 20 pipe diameters (80 inches) . The actual bend radius was 91 inches. Thus, the sparger material should be in the solution annealed condition with an acceptable amount of cold work. To confirm this, a review was made of all available manufacturing and material records at the sparger manufacturer's plant. These records show that (1) the material supplied was A312, Type 304, solution annealed stainless steel pipe which was rapidly cooled, (2) it was cold formed to the required radius of 91 inches, and (3) there is no evidence of any subsequent heat treatment. Welding and assembly of the spargers was performed after cold forming of the 3-1/2" pipes.
The susceptibility to intergranular stress corrosion cracking ;
(IGSCC) has been shown to be increased by any local co.1d work that materials may receive as a result of cold straightening or bending during fabrication, fit-up, or installation. Tests performed by GE as part of the pipe cracking evaluation reported in NEDO - 21000 and actual TITLE RAGE REVISION NO. ! DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 8 1 11/15/78
i service experience in BWR's have shown that stress corrosion cracks can initiate in the heat affected zones of welds in such pipes. Accordingly, stress corrosion is considered to be the most probable cause of crack initiation in the area of the local cold work or the heat affected zone of the weld.
As discussed above, visual examinations and air bubble tests indicate that the crack extends at least from the top centerline around the inboard side for about 220o on the sparger OD and penetrates the wall over an are length of about 135 . Because the crack length appears to be longer on the OD of the sparger pipe than the ID, it can be inferred that the crack propagated from the OD of the sparger inward. Further, the location of the crack immediately adjacent to a radial support bracket and its location and extent over the inner half of the sparger are consistent with an applied loading which imposes a high bend'ing moment at the crack location. The direction of the moment would be such that the portions of the sparger nearer the reactor centerline I are'in tension and the portions nearer the shroud in compression.
Possible sources of such a bending moment have been evaluated. Normal service loadings (thermal conditions, flow forces, vibratory loadings) result in very low applied loads and stresses, and are insufficient to explain any propagation. Initiation of core spray at reactor operating temperature would result in higher stresses; however, no TITLE PAGE REVISION NO. DATE l Repair Proposal No. 320-78-1 l OCNGS Core Spray Sparger No. 2 9 1 11/15/78 l
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l such event has occurred to date. The most probable loading which could i apply a high bending stress as described above are forces applied during sparger installation to force the sparger to conform to the location f of the radial support brackets. For example, calculations show that !
deflection of the sparger of as much as 3/16" over two support spans l would impose near yield level stresses in the area which is now cracked.
This loading is considered to be the most probable cause of crack :
propagation' and is consistent with all observations. /j ;
i Visual examinations and review of video tapes of these examinations -
support the above hypothesis. These examinations indicate the following:
- 1. The crack in the upper sparger at location 2080 is the only crack t
found in either of the two sparger assemblies.
- 2. The examinations show no signs of wear, fretting, vibration, or P movement of any of the spargers in their support brackets as'a result of service loadings.
- 3. Distinct marks are apparent on this sparger arm adjacent to the
( crack which could be the result of applied loads during installation.
c TITLE RAGE I REVISION NO. DATE Repair Proposal No. 320-78-1 10 OCNGS Core Spray Sparger No. 2 1 11/15/78 e
5.0 EVALUATION OF PRESENT CORE SPRAY SPARGER CONFIGURATTON l
Analyses have been performed to evaluate the significance of the observed '
crack at 2080 in the upper core spray sparger. Specifically, the ,
r potential effect of such a crack on the structural adequacy of the sparger and the hydraulic performance of the sparger and core spray i
system were analyzed. The potential for additional crack growth has ;
also been evaluated. The results of these evaluations are summarized (
below: l I
, A. Potential for Additional Crack Growth I As discussed in Section 4.0, the only type of loading which can be l t
postulated which is consistent with the observed crack location and i I
extent, and which can reasonably be expected to exist, is a bending f I
moment load. There is no known mechanism (with the exception .of !
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4 core spray system actuation which has not occurred) that can impose
- a significant tensile load on the sparger in the circumferential direction (i.e. , along the axis of the 3-1/2" sparger pipe) . This makes it highly unlikely that any such crack could propagate around 1 , ,
i the full 3600 circumference of the sparger. (It should be noted !
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I that even during a core spray actuation less than .02 square inches l 1
of sparger material cross-section would be required to withstand i 1 ,
, the axial force resulting from core spray differential pressure) . l With regard to the possibility of initiation and growth of signifi-cant si:e cracks at other locations, the following is considered pertinent:
i TITLE RAGE REVHNON NO. DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 11 1 11/1S/78 l-
- 1. Inspections and air tests have revealed no additional cracks i or crack-like indications. These inspections include the accessible portions of the spargers and 5" inlet piping, and covers the portions most likely to be affected by the same mechanisms which apparently led to the existing crack. If other cracks were to have occurred, there is high probability [
l g they would have occurred in these locations. l
- 2. The effects of long-term neutron radiation have been shown to I 1
include the lowering of susceptibility to intergranular stress )
corrosion cracking (IGSCC) initiation in stainless steels. j I
(See Reference 3.2). To summarize the reference document:
Bend specimens were exposed to BWR water chemistry environment in the Dresden 1 reactor. The bend specimens located in the i reactor core region had a lower incidence of cracks than control ;
specimens situated out of the high neutron flux, With the type of loading on these specimens (or postulated on the spargers), ;
the radiation serves to both relax the stresses and strengthen ,
the material. The OCNGS core spray sparger piping is estimated to have seen'a fluence of 10 19 to 10.20 NVT. In fluences of 1 x 1020 NVT, the yield strength of this material will roughly double thereby reducing the probability of plastic deformation and the possibility of IGSCC for the type of loading postulated in the sparger. ;
- 3. Observable cracks have not occurred in the balance of the sparger !
l piping (as confirmed by inspection) and these spargers have been TITLE RAGE REVISON NO. DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 12 1 11/15/78 l
l
in service for over 8 years. IGSCC is much less likely to occur in the future due to the radiation hardening effect as discussed. This logic leads to the conclusion that the existing crack occurred during the first few years of plant operation before significant radiation hardening occurred and that it is unlikely that additional cracking will occur.
B. Structural Evaluation of Sparger Configuration Analyses have been performed to determine the effect of the observed crack on the structural adequacy of the sparger. These analyses demonstrate that even if the crack were to propagate through the sparger wall thickness over 3600 of its circumference, the remaining
" fixed" and " free" ends of the sparger (1) would be adequately supported for all anticipated loadings, (2) would not be over stressed, and (3) could not become loose parts. The main reasons for this are that (1) each piece of sparger would continue to be
- supported by two or more radial support brackets, and (2) gross circumferential motion of the " free" sparger segment is prevented !
by the core spray nozzles which are as close as 3/16" to adjacent support brackets. Loadings considered in this evaluation included flow forces, differential thermal expansion, pressure differential, and resulting jet forces during core spray actuation, dead weight, l seismic,and vibratory loadings. On this basis, the present sparger configuration, even with a through-wall crack around the full circumference of the sparger, is considered structurally adequate '
to preclude any parts from becoming loose parts within the reactor.
TITLE RAGE- REVISON NO. DATE Repair Proposal No. 370-78-1 OCNGS Core Spray Sparger No. 2 13 1 11/15/78
.---a
C. Performance Evaluation of Sparger Configuration An additional evaluation has been made to assess the potential effect of the crack at location 2080 on core spray system performance. As
- in the structural evaluations, it was conservatively assumed that the crack at 2080 in the upper sparger propagates through the cross section of the sparger as if the sparger were saw cut at that location. Were the system actuated, injection of cold core spray water would cool the sparger relative to the shroud. In the assumed condition, the resulting sparger contraction in the circumferential i direction would tend to open the assumed "saw-cut" by about 0.4".
Combined with the available clearance of approximately 3/16" between the nearby core spray no::le at 2ngo and its support bracket at !
208-1/20 , the "saw-cut" could open by about 0.6". Calculations ,
t indicate that approximately 20% of the 3400 gpm core spray design !
t flow could enter the core through the postulated crack rather than l through the core spray nozzles. ,
t Operation of the Core Spray System No. 2 in this condition would result in a reduction of flow through all nozzles in System No. 2 only. In addition, the sparger arms containing the crack would suffer flow reductions more significant than the other three sparger arms in the System No. 2 sparger assembly. This significant reduction in nozzle flow would most likely alter distribution of the core spray water beyond the limits which could be shown to be satisfactory, although !
core flooding capability would not be adversely affected.
TITLE RAGE REVISON NO. DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 14 1 11/15/78
- i e
6.0 PLANNED CORRECTIVE ACTIONS While the structural evaluation results are acceptable, the performance ;
i evaluation discussed in Section 5.0 demonstrates that the present condition of the upper core spray sparger will most likely prevent achieving the design flow distribution. To assure that both of the core spray systems (System No. I and No. 2) will have full design !
capability, a structural support will be installed prior to startup of the reactor to preclude crack opening which would detrimentally ;
affect sparger and system performance. >
i The additional structural support is shown on Reference 3.1 and consists i of a 19" long clamp assembly which will be attached to the upper core spray sparger over and on either side of the cracked area at 2080 The clamp assembly will be machined, based on as-built dimensions of the l sparger,to fit around the two spray nozzle bosses on either side of i location 2080 . A significant clamping force will be applied at installation by the use of four 3/4" bolts. The clamp assembly will [
prevent relative movement of the two sectior.s of the sparger even if !
the crack were to propagate through the sparger cross section and will preclude any significant opening of the observed crack. The clamp !
t assembly also strengthens the core spray sparger in the area of the crack.
The clamp assembly is fabricated from solution annealed and water-quenched Type 304 stainless steel (all parts). This material has been demonstrated by GE to have good resistance of IGSCC in the BWR TITLE PAGE REVISION NO. DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger_No. 2 15 1 11/15/78 I
1 I
environment. The clamping bolts will be positively locked using Class A-type locking cups and a special crimping tool.
The assembly is held in place by virtue of clamping forces applied with a coverage greater than 1800 The initial clamping forces applied will not result in an over-stress condition in the sparger. Once clamped in place, the jaws of the clamp are open 1/4" less than the OD of the sparger. To remove the clamp without removing the clamping bolts would require deforming the clamp or the sparger pipe. As a backup to the clamping forces, the clamp is restrained by two no::les encompassed by the clamp. The amount of postulated movement, neglecting clamping forces, is dependent on the clearance between the bracket and the two no::les. These clearances will be less than 1/32".
The clamp assembly has been evaluated with respect to loadings caused by flow, differerdial thermal expansion, pressure differential, and resulting jet forces during core spray actuation; dead weight, seismic, i and vibratory loadings, and is considered structurally adequate.
s During core spray initiation, the clamping forces of the assembly on the sparger could be reduced to one-half the initial -value due to differential thermal shrinkage. The resulting clamping force would still be sufficient to hold the sparger together against internal differential pressure and frictional loads due to thermal contraction.
Therefore, the crack would not become larger even when the sparger is subjected to the loads associated with a core spray initiation. The TITLE RAGE REVISON NO. DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger.No. 2 16 1 11/15/78
-._ . _ - _ m
flow loss through the crack in this configuration is estimated to be below 1% of the system flow.
1 Conservatively, assuming that there is no clamping force on the pipe j during core spray initiation, the maximum amount of pipe separation
, would be less than 1/16". This limit is assured by the limitations of less than 1/32" clearance between the brackets'and the two no::les encompassed by the clamp.
t i
Upon completion of installaticn, the clamp will be checked by both underwater television inspection and measurement tools to ensure that the clamp is firmly attached to the sparger. This will ensure that the clamp is properly installed, will not come loose during reactor operation, and will provide a set of baseline measurements for confirmation of continued proper fit during future inspections.
The performance of the intact core spray system (System No.1) is not affected by the addition of the repair clamp assembly.
s The integrity of the core spray spargers and the supplemental clamp assembly will be monitored by augmented in-service examinations. The program and schedule for these supplemental inspections will be developed over the next several months and will include visual examina-tions using remote viewing equipment during the next scheduled refueling outage.
I i
TITLE PAGE REVISION NO. DATE
[
l Repair Proposal No. 320-78-1 l OCNGS Core Spray Sparger.No. 2 17 1 11/15/78 l
3 - _ _
7.0 SAFETY EVALUATION The core spray systems at OCNGS are the primary means of Emergency Core Cooling in the event of a loss of coolant accident and a simultaneous loss of off-site electrical power. The capability of these systems is analyzed and presented in docketed LOCA analyses (References 3.3 and 3.4) which are currently pending before the NRC.
The model used for these analyses is described in References 3.5, 3.6, and 3.7 and has received NRC and ACRS approval (Reference 3.8) .
1 s
A failure modes and effects analysis of Oyster Creek ECCS done in' 1975 resulted in a modification to the core spray systems (Reference 3.9) which assures the operability of both of the systems even under the assumption of a single failure in each system. Consequently, two core spray systems would be available for all break locations with the exception of the situation in which the accident initiating break is in one of the core spray lines leading to the reactor vessel.
Independent calculations have shown that for a core spray line break, spray is not required for cooling and merely the flow through the other system is adequate for reflooding the reactor vescel and keeping the reactor core cool.
LOCA analyses assume no credit for core spray cooling of the fuel bundles until the rated flow of 3400 gpm is achieved at a reactor pressure of 110 psi. Only after reactor pressure is reduced by blowdown or Automatic Depressurization System (ADS) operation to 110 psi or below, is a flow of 3400 gpm assumed even though actual TITLE PAGE REVISON NO. DATE ,
Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger.No. 2 18 1 11/15/78 .
flow would commence at a pressure of 285 psi and increase as reactor
- pressure is decreased. This is one of several conservative assumptions in the ECCS analysis and in the plant design.
The safety objective of this repair is to demonstrate that for all accident break locations and sizes that sufficient core spray flow and distribution are available to ensure that the assumptions of the docketed ECCS Analyses are not violated. This requires that the adequate quantity of core spray water be delivered to the core and that it be distributed in a way that assures at least the minimum required flow to each fuel bundle.
This demonstration can be accomplished in two ways:
First, without the repair, Core Spray System No. 2 flow quantity to the core can be assured, but its distribution cannot be guaranteed.
Nevertheless, with the exception of one specific break, adequate core spray flow and distribution can be assured from System No. 1
(
even in the event of a single failure. (Reference 3.9). The one specific break for which this is not true is a break in the Core Spray System No.1 outside the reactor vessel. However, analyses (Reference 3.4 and additions 1 information supporting that submittal) show that spray distribution is not necessary in this case as long as the assumed volume of water reaches the core for reflooding purposes.
This can be accomplished by Core Spray System No. 2 in its degraded condition.
TITLE _.
PAGE REVISION NO. DATE Repair Proposal No. 320-78-1 GCNCS Core Spray Sparger No. 2
~
19 1 11/15/78
Second, to ensure an even greater reliability of core spray avail-ability and performance and not reduce the margins of safety included in the station design and in its safety analysis, the ;
. repair discussed in Section 6.0 will restore Core Spray System i No. 2 to its full design capability and will thus be able to supply not only the proper flow but also will be able to supply
. it with an adequate distribution.
Core Spray System No. 2 in the repaired condition is ca>able of supplying 3400 gpm spray flow at a reactor pressure ci 110 psi.
GE has provided analyses in which the leakage out *.ne sparger crack was conservatively calculated to be less than 2.0% (61 gpm) by assuming the crack propagated 3600 around the sparger and opened to 1/16" wide with no flow restriction from the clamp.
The clamp assembly wil1 reduce the leakage flow, prevent further crack opening, and diffuse the leakage and deflect it toward the shroud or along the sparger axially and away from the spray nozzle flow of both the upper and lower spargers.
GE hydraulic analysis of the cracked sparger indicates that the leakage out the crack does not result in reduced flows to nozzles in that arm as well as throughout the sparger ring. Attachment II, " Core Spray Eval ~uation", shows that to assure adequate distribution the flow in each nozzle must be raised to approximately the flow from that nozzle under the nominal condition. To accomplish this for the assumed 1/16", 360 crack, the system flow must be TITLE PAGE REVISION NO. DATE Repair Proposal No. 320-78-1 20 OCNGS Core Spray Sparger No. 2 1 11/1S/78
increased 240 gpm above the nominal 3400 gpm. In this condition, all no::les would have flows between 0% and 65 above the nominal case and this would provide adequate distribution.
Core Spray System No. 2 has been demonstrated to be able to supply this flow at 110 psi reactor pressure assuming the worst single failure in the system. Therefore, adequate core spray flow from System No. 2 is provided as is adequate distribution over the core; and therefore, Core Spray System No. 2 is operable in the repaired condition even treating the repair conservatively.
A summary of these safety considerations, the safety significance of other features of the repair, and the conclusions concerning reactor safety are included in the attached Safety Evaluation (Attachment I).
Attachment II, " Core Spray Evaluation", provides the bases for concluding that Core Spray System No. 2 sparger will provide adequate flow and adequate spray distribution to the reactor core.
t TITLE RAGE "
REVISON NO. DATE Repair Proposal No. 320-78-1 OCNGS Core Spray Sparger No. 2 21 1 11/15/78
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l Sketch of the Crack in the l Upper Core Soray Sparger FIGURE 3 -
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NOTE: THIS .BR ACKET IS AT REATOR VESSEL AZlMUTH 208 1/2 L
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FidURE 4 SKETCH OF THE CRACK IN THE UPPER CORE SPR AY SPARGER ,
BOTTOM VIEW 1
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FIGURE 5 . j b '.;0 ; : - : ej : ;. f
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uf CROSS-SECTION CHARACTERIZATION -
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$.' :' iii li; f c
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. .- .-.m , ,, . . . _ - . . . _ _ , - _ , . _ . . . - _ _ ,- , . _ . . . . ._
9 I-t ATTACIB1ENT I f
to j REPAIR PROPOSAL NO. 320-78-1 OCNGS CORE SPRAY SPARGER NO. 2 l
l t
6 SAFETY EVALUATION November 2, 1978 r
TITLE PAGE REVISION NO. DATE e
SAFETY EVALUATION SlMLARY
- 1. Change / Test / Experiment subject:
Core Spray Sparger Repair Proposal
- 2. Personnel Responsible for Safety Evaluation:
J. Knubel
- 3. Systems / Subsystems / Components affected:
Core Spray System II/Sparger 4.
Conclusion:
s The repair does not present an unreviewed safety question if i it can be shown that Core Spray System II can deliver 3640 gpm to l ;
the reactor at a Reactor Pressure of 110 psig.
- 5. Technical Specifications affected: l None j
- 6. FDSAR Section affected:
None
- 7. A. What Plant Procedures were reviewed in the Evaluation: 610.3.005 610.4.002
- , B. What changes if any are recommended s
Change Procedure 610.4.002 to assure System II flow is t at least 3640 gpm with a reactor pressure of 110 psig. [
l
- 8. Recommendations .
A core spray flow of 3640 gpm at a reactor pressure of 110 psig l:
must be shown for this not to be considered an unreviewed safety question as defined in 10 CFR 50.S9.
- 9. Comment None Safety Evaluatio Submitted by:
-: 4 '
[/ J: Knubel
{ 37) ?.. filf ,
Revised Nov.~ 9, 1978 . lll- Date .
ll -
I. Subject and Purpose of Proposed Change / Test / Experiment A. Core Spray Sparger Repair Proposal B. The purpose of the proposed modification is to repair the cracked core spray sparger in such a fashion that the structural integrity of the sparger and core spray performance is assured.
II. Description of Proposed Change / Test / Experiment A. System affected - Core spray system B. Subsystem / component affected - System II sparger.
C. Reference Drawings
- 1. MPR SK-1083-12-01
- 2. GE 104R858 (Fig.1)
- 3. Sketch (Fig. 2)
- 4. Sketch (Fig. 3)
D. This system and its components are described in the following documents:
- 1. Plant system description Vol. 1
- 2. FDSAR Chapter VI-6
- 3. Technical Specifications Sections 3.4 and 4.4 l 4. Amendments 18 6 30 to the FDSAR III. Effect on Safety A. The safety functions of this system are defined in:
- 2. Oyster Creek LOCA analyses using ENC NJP-BNR ECCS evaluation Model XN-NF-77-55 Rev. 1 and Rev. 2.
- 3. JCPSL Co. ECCS modification core spray electrical crossconnect.
Attachment II Rev. 1 July 15, 197S.
B. The safety function of this system and components is to provide adequate cooling flow to the reactor core under a spectrum of Loss of Coolant Accidents. The purpose of the sparger is to distribute the core spray water to the fuel bundles in such a fashion that hot spots do not occur.
which could result in a Peak cladding temperature exceeding 2200*F. l
s C. 1. The addition of the bracket assembly to the core spray sparger I will hold the sparger in such a way that if the crack were to propogate !
360*, the maximum opening that could occur would 'oe 1/16". This l is based on the clearances of the bracket to no::les and takes no credit for clamping" forces. The bracket assembly is constructed entirely of type 304 solution annealed stainless steel which is the same material as the sparger. The bracket is held in place by four (4) 3/4" bolts that are pre-loaded and locked in place at 3 points by Class A type locking caps. Structural evaluations considering normal operation (water / steam flow, thermal I-cycling, and vibration) and accident conditions (core spray hydraulic forces, differential thermal contraction and seismic forces) have shown that the bracket will limit the opening of the crack to less than or equal to 1/16 inch and that the bracket will remain in place. The choice of materials, design, bolt preloading and use of locking caps assures the bracket itself will not come loose. In order for the bracket O to be forcibly removed from the sparger the bracket or pipe would have to be deformed at least 1/4 inch and this would require a force on the order of 5000 lbs. There is no conceivable mechanism that could apply this type of force to the bracket.
A 360 crack 1/16" wide on a sparger would conservatively divert less than 2% (61 gpm) of system core spray flow through it.
This in itself would not affect the ability of the core spray system to provide 3400 gpm to the core at a reactor pressure of 110 psig, but some no::le flow would be diverted through the crack. General Electric has calculated that the minimum flow from each no::le will be at least equivalent to that obtained at 3400 gpm from an uncracked sparger if the system flow is 3640 gpm. l In addition the installation of the bracket will not interfere with the core spray distribution pattern from System I or II and will not allow water from the crack to directly impinge on spray from the sparger no::les.
- 2. The addition of the bracket will not increase the probability of the initiation of an accident as described in the FDSAR.
l
- 3. The addition of the bracket does not change the consequences of the events in the safety analyses of the FDSAR.
- 4. No margins of safety as described or defined in the bases of I the Technical Specification will be reduced.
i l
D. FDSAR or Tech Spec changes: None.
l E. Plant Procedures 610.3.005 610.4.002 l t
n
- ,_-- +. ,em, - - p wg , - - -cy
i IV. Conclusions A. The purpose of the modification is to repair the cracked core spray ,
sparger in such a fashion that the structural integrity of the i sparger and core spray performance is assured. !
B. If it can be shown that core spray system II can deliver 3640 g [
. gpm to the reactor at a reactor pressure of 110 psig, the {
performance of that core spray system considering a 360 1/16" [
inch wide crack is adequate. ;
With the proposed modifications the structural integrity of the f core spray sparger is assured.
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ATTACIBtENT II :
to REPAIR PROPOSAL NO. 320-78-1 OCNGS CORE SPRAY SPARGER NO. 2
/
i t
CORE SPRAY EVALUATION
! November 13, 1978 l
\
i L
E I
TITLE PAGE REVISION NO. DATE
OYSTER CREEK CORE SPRAY EVALUATION ;
I. Introduction
=-
burin; in-service inspection, a crack was found in one arm of the upper I core spray sparger at the Oyster Creek Nuclear Power Plant. An evaluation :
was performed to determine the capabilities of the core spray system with j the repair clamp installed on the cracked sparger. This supplement provides !
detailed resslts of previous analyses and quantitative support for the [
position that acceptable core spray distribution would be maintained. ;
i II. Discussion [
f The flow" distribution along both halves of the core spray header was ;
determined for several conditions. The individual no::le flows for the j rated system flow of 3400 gpm were determined for the intact spargers to ;
< provide a base case for comparison. The no::le flows were also calculated i l
for the case of one cracked sparger (1/16-inch circumferential gap) with a system flow of 3700 gym and for both spargers intact with a system flow :*
of 3700 gpm. The nostle flows for all cases were normali:ed by the average flow for each no::le type for the rated flow of 3400 gpm. These results ,
are shown in Figure 1. The calculated no: le flows for the rated flow [
condition have been compared with measured no::le flows and there is very ;
good agreement. Note that there is considerable variation in the no::le flow along each sparger arm. For the 3400 gpm case, the variation between I the no::le nearest the inlet and the end no::le is on the order of 35%.
For the 3700 gpm cracked sparger case, the maximum variation in no::le flows occurs along the cracked arm and is only on the order of 40%. :
This is not a very significant deviation from the intact sparger condition and indicates that the presence of the crack does not sig- .
nificantly alter the performance of the sparger. Notice also for the ,
3700 gpm cracked sparger case that all of the no::le flow rates are greater than for the rated flow condition; the system flow has been e s increased so that there are no decreases in no::le flow rates. Also, !
shown in Figure 1 is the flow distribution for a system flow of 3700 ,
gpm with an intact sparger. This represents the conditions which ;
would exist if the crack remained at or near its present size so that -
there was no significant crack flow. ;
It has been determined that assuming a 1/16-inch 3600 crack that minimum ,
input flow required to achieve this is 3640 gpm. The table below compares i the effects of various crack sizes and system flows on nos:le flows, ;
no::le flow variations, and crack flows:
Crack Flow Min. No::le Max. No::le Crack !
Size Rate Flow Change Flow Change Flow [
(Inch) _gpm)
( (%) (%) gpm), l
.032 3600 2 6 31 l
.063 3640 0 6 60
- .063 3700 1.4 9 61- l
.125 3800 -3 13 117
=
. - . . , . - . , --v , , . , . _ - - _ , . _ _ - . . - . . .y
- During verification of the Oyster Creek sparger design, the spray distribution across the core was measured for system flow rates of 3100, 3400, and 4500 gpm.
Acceptable spray distribution was measured in all cases. No::le flow distri-bution curves for the 3100 and 4500 gpm cases are shown in Figure 1 to demonstrate the range of flow rates which provide acceptable performance.
. The variation in no::le flow rates between the no::le nearest the inlet and the end no::le for the 4500 gpm system flow is on the order of 45%.
This is greater than the variation existing in the 3640 or 3700 gpm cracked sparger case. The fact that acceptable spray distribution was measured for system flow rates of 3100, 3400, and 4500 gpm also indicates that at least within this range the sparger design is nat very sensitive to flow variations and acceptable spray distribution is achieved.
III. Conclusion Test measurements and this analysis have shown no::le flow variations along the sparger of the same order as would exist in the cracked sparger with,a system flow of 3640 gpm. Test measurements have also shown the sparger is not sensitive to changes in the system flow and provides acceptable spray distribution with system flows from 3100 to 4500 gpm. Based on this, it is concluded that the no::le flow variations that could exist with a system flow rate of 3640 or 3700 gpm if the crack increased to a 1/16-inch circum-ferential gap are within defined acceptable limits and that acceptable core spray distribution would be maintained.
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.5-SPARCsER CRACK SPA AGER IN LE.T LOC ATIO N IMLET
.4- (208 9 ld5 idO 255 OdO 1$0 240 330 015 060 CIRCUMFERENTI AL LOCATION l_EGEND: -- --
4500 SPm TE.ST UPPER BOUND 3100 SPM \MTACK. SPARGER 3-~l00 3 PM CRACKED SPAPGER
- 3400 SPM RATED FLOW INTACT SPARGER 3100 S PW TE.ST LOWER SOUND OYSTER CREEK NUCLEAR GENERATING STATION NORMAll7"O NOZZLE FLOW RATE 'S A FUNCTION vF CIRCUMFER ENTI AL LuCATION
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