ML19322E817
| ML19322E817 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 03/31/1980 |
| From: | JERSEY CENTRAL POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML19322E816 | List: |
| References | |
| NUDOCS 8004020320 | |
| Download: ML19322E817 (66) | |
Text
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I JERSEY CENTRAL POWER 6 LIGilT COMPANY OYSTER CREEK NUCLEAR GENERATING STATION Provisional Operation License No. DPR-16 Technical Specification Change Request No. 83 Docket No. 50-219 Applicant submits, by this Technical Specification Change Request No. 83 to the Oyster Creek Nuclear Generating Station Technical Specifications, changes to section 4.3 which covers surveilance requirements for the Core Spray System.
JERSEY CENTRAL POWER 6 LIGilT COMPANY BY ,
v yice pr den
~
STATE OF NEW JERSEY COUNTY OF MORRIS Sworn and subscribed to before me this 3/ # day of 3/gw/ ___, 1980.}auL f C~.
~ Nota (y Pbb ic MARILYN R. JONES No7ARY PUOUC of IC# JCUEY My Commisuon Expirva Aprd 4,1/fd 8 004 020 MO.
i 1 UNITED STATES OF AMERICA l i j NUCLEAR REGULATORY C05B!ISSION e IN Tile h!ATTER OF )
, ) DOCKET NO. 50-219 JERSEY CEhTRAL POWER 6 LIGilT COMPANY )
'1 CERTIFICATE OF SERVICE i This is to certify that a copy of Technical Specification Change
; Request No. 83 for the Oyster Creek Nuclear Generating Station Technical Specifications, filed with the U.S. Nucicar Regulatory Commission on i Ebrch 31, 1980 has this 31st day of hbrch, 1980 been served on the Flayor of Lacey Township, Ocean County, New Jersey by deposit in the United States mail addressed as follows:
The Honorable Henry Von Spreckelsen Mayor of Lacey Township P.O. Box 475 l Forked Rivc., New Jersey 08731 JERSEY CENTRAL POWER 6 LIGitT COMPANY BY: gg;pf VicePres/ent[ dated: March 31, 1980 J t s
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-;.. Jersey Central Power & Light Company % $g , 3 E
e d Ihd .ff k Madison Avenue at Punch Bowl Road Morristown, New Jersey 07960 (201)455-8200 March 31, 1980 The lionorabic lienry Von Spreckelsen Mayor of Lacey Township P. O. Box 47S Forked River, New Jersey 08731
Dear Fhyor Von Spreckelsen:
Enclosed herewith is one copy of Technical Specification Change Request No. 83 for the Oyster Crack Nucicar Generating Station Technical Specifications. These documents were filed with the U.S. Nuc1 car Regulatory Commission on Very truly yours Ivan R. Fin ek, r. Vice Presid>nt 4 la Enclosure i Jersey Centra! Power & Light Company is a Member of tne Genera! Pubhc Utihtecs System
JERSEY CEhTRAL POWER 6 LIGilT C0!!PANY OYSTER CREEK NUCLEAR GENERATING STATION PROVISIONAL OPERATING 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:
Section 4.3.
- 2. Extent of changes:
Inservice inspection of the core spray spargers is being augmented.
- 3. Changes requested:
Replace page 4.3-8 with the attached page.
- 4. Discussion:
This change is being made in suppo. . of the repair of the cracks in the core spray spargers during the 1980 refueling outage. 1
4.3-8 TABLE 4.3.1 EXAMINATION SCHEDULE OF REACTOR COOLANT SYSTEM NOTES:
- 1. UT Ultrasonic examinatica RT Radiographic examination (UT acceptable alternate for RT)
VT Examination by viewing
- 2. a. Inspect same sampic 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.
- c. Inspect partial sample during at laast two inspections such that 10% of the penetrations are inspected during the first 5 years of operation.
- d. Normal maintenance observations - Examination by viewing, where accessible, during maintenance.
- c. Inspections, to the extent practicable, to assure continued functional capability of both spargers and the repair assemblics shall be carried out during each refueling outage beginning in 1981.
- 3. The examination schedule of Table 4.3.1, extent of examination, inspection process, and inspection frequency shall be reviewed after the fourth year of operation and a revised specification for subsequent inservice inspection developed.
Technical Specification Change Request No. 83 dafety Evaluation ! During the 1980 refueling outage additional cracks were discovered by inservice inspection of the spargers of the Core Spray System. The cracks and their repair are described by a Repair Proposal and Safety Evaluation.
- This information will be presented to the NRC on April 1,1980. .
The PORC and GORB agreed that augmented inservice inspection of the core spray spargers and of the repair assemblics was desirable. This Technical Specification change would require that an inspection of both core spray spargers and of the repair assemblics be performed at each of the future refueling outages, starting in 1981. At the completion of installation of an improved system or spargers, the inspection interval would revert to that existing before the cracks were discovered. Other changes, of course, could be made depending on the results of the augmented inservice inspection and the installation of improved system or spargers. Although the proposed sparger crack repair program does not restore the core spray sparger to its original design condition, there is reasonabic
- assurance that in ths. unlikely event the core spray system would be called upon to function during operation, the system including the spargers would perform its intended function in accordance with the original design criteria.
Since this Technical Specification change request would serve only to increase inservice inspection, it will in no way reduce 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. 4 9 e
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B ; 3.f.9Y 7[c g)J Jersey Central Power 29.EEEEME- & Light Company T REPAIR PROPOSAL NO. 475-01 OYSTER CREEK NUCLEAR GENERATING STATION CORE SPRAY SYSTEM SPARGER REPAIR Prepared By: J. S. Chardos W. R. Schmidt Approved By: Am M[ l T. bK Crimmins , p. Manager i Generation Engineering l i I Title Page Revision No. Date 1 T. 0 3/31/80
I,1ST OF EPPECTIVE PAGES Pago No. Revision No. Date T 0 3/31/80 1 0 3/31/80 11 0 3/31/80 1 0 3/31/80 2 0 3/31/80 3 0 3/31/80 4 0 3/31/80 5 0 3/31/80 6 0 3/31/80 7 0 3/31/80 8 . 0 3/31/80 9 0 3/31/80 10 0 3/31/80 i 11 0 3/31/80 12 0 3/31/80 , 13 0 3/31/80 14 0 3/31/80 15 0 3/31/80 16 0 3/31/80 - 17 0 3/31/80 18 0 3/31/80 19 0 3/31/80 20 0 3/31/80 21 0 3/31/80 22 0 3/31/80 23 0 3/31/80 24 0 3/31/80 25 0 3/31/80 26 0 3/31/80 27 0 3/31/80 28 0 3/31/80 29 0 3/31/80 30 0 3/31/80 , 31 0 3/31/80 1 32 0 3/31/80 l 33 0 3/31/80 l 34 0 3/31/80 TITLF. PAGE REVISION NO. DATE Hopair Proposal No. 475-01 OCNGS Core Spray Syntem Sparger Hepair 1 0 3/31/80 i
TABLE OF CONTENTS
1.0 INTRODUCTION
2.0 BACKGROUND
AND DESCRIPTION OF CORE SPRAY SPARGERS 3.0 RESULTS OF 1980 INSPECTIONS AND ' RESTS 4.0 EVALUATION OF CRACKING 5.0 CORRECTIVE ACTION 6.O SAFETY EVALUATION
7.0 REFERENCES
FIGURES l 1
- 1. REACTOR VESSEL CROSS-SECTION
- 2. UPPER CORE SPRAY SPARGER PLAN VIEW
- 3. SYSTEM I CRACK LOCATIONS l l
- 4. UPPER CORE SPRAY SPARGER AT AZIMUTH 208* J
- 5. SYSTEM II CRACK LOCATIONS
- 6. SYSTEM I CLAMP LOCATIONS l
- 7. SYSTEM II CLAMP LOCATIONS I ATTACHMENTS
- 1.
SUMMARY
OF RESULTS FROM UT EXAMINATIONS
~
,"]i ES
- 1.
SUMMARY
OF VISUAL AND ULTRASONIC EXAMINATIONS
- 2. CRITERIA FOR CLASSIFYING INDICATIONS AS CRACKS I l
TITLE - PAGE REVISION NO. DATE
~
Rcpair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair ii 0 3/31/80
1.0 INTRODUCTION
Scheduled in-service inspection of reactor internals during the Fall 1978 refueling outage at Oy' ster Creek identified a linear indication i. a portion of one of the two core spray system spargers inside the reactor vessel. Subsequent tetus showed that the indication in the core spray sparger is a crack which penetrates the wall of the 3-1/2 inch Schedule 40S sparger over about 135* of its circumference. Action was taken
~
during the Fall 1978 outage to strengthen the sparger at the crack location by the installation of a mechani-cal clamp assembly. (
Reference:
Repair Proposal No. 320-78-1.) Visual and ultrasonic examinations conducted during the Winter 1980 refueling outage disclosed the pres-ence of additional cracks. The purpose of this re-port is to: (1) Summarize results of examinations, tests, evaluations, and analyses performed to establish the: (a) cause of the cracking, (b) potential for more cracking, TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS ore Spray System Sparger Repair 1 0 3/31/80
(c) effect of the cracking on the sparger's structural design capability, and (d) effect on system ar.d sparger functional capability (2) Describe corrective actions to be taken and the bases for them. e TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 2 0 3/31/80
2.0 BACKGROUND
AND DESCRIPTION OF CORE SPARY SPARGERS The Oyster Creek reactor vessel contains two independ-ent core spray sparger assemblies which are fed by two separate core spray systems. Each of these sys-tems is provided with fully redundant pumps, valves, power supplies, controls and instrumentation, so that each system can perform the safety function in the presence of a single failure in that system. Only one system need peEform to accomplish the safety objective. Each core spray sparger assembly consists of two 180* segments of formed 3-1/2 inch Schedule 40s stainless steel piping, each of which contains 56 spray nozzles (112 nozzles total per sparger ring assembly). Each 180* segment consists of two 90* arms which are con-nected to a 5 inch Schedule 40 inlet pipe. When the system is actuated, core spray water is directed through a reactor vessel nozzle and a penetration in the shroud to both segments of the core spray sparger 1 l assembly, thus supplying water to the reactor core from all directions. The nozzles are designed to provide a spray pattern that ensures each fuel bundle receives cooling flow. Tests of the system in a mock-up have shown that cooling flow is relatively insensitive to system flow. Adequate cooling flow can be met at i TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Pepair 3 0 3/31/80
--m.
system flows from 3100gpm to 4500gpm Each 180' segment of the spargers is supported at the location of the 5 inch inlet pipe connection which is welded to the shroud and by three, approximately I equally spaced support brackets on either side of the ! central inlet pipe connection. The support brackets consist of 3/8" thick vertical gusset plates, with 1-1/2" wide bearing pads, which support the sparger arms in the radial and vertical directions. The spar-ger arms are free to slide in a circumferential direc-tion (relative to their inlet connection to the shroud) as required to accommodate any differential thermal expansion betueen the shroud and the sparger 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 the upper core spray sparger (designated System II) is pre-sented in Figure 2. In-service inspections performed during the Fall 1978 outage revealed a single crack at azimuth 208' (See Figure 4) in the upper sparger. This crack was de-termined to extend approximately halfway around the sparger circumference by examination. By introduction TITLE PAGE REV;SION NO. DATE Repair Proposal llo. 475-01 OCNGS Core Spray System Sparger Repair 4 0 3/31/80
of air into the sparger and observation of gas bubbles leaking from the crack, it was concluded that the crack was through-wall for about 135*. Although structural and hydraulic analyses indicated that the cracked sparger would be adequate for continued opera-tion, an additional mechanical support was installed to provide additionai margin and to assure that both core spray systems will have full design capability. i 1 TITLE - PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS , . Core Spray System Sparger Repair 5 0 3/31/80
l , 3.0 RESULTS OF 1980 INSPECTIONS AND TESTS Visual examinations of the sparners using remote un-derwater television were performed during the Winter 1980 refueling outage. These examinations showed that the repair clamp assembly remains in place in the same i position as installed in 1978, that there has been no degradation of the repair clamp in any way and that there is no additional cracking in the piping adjacent to the repair clamp. The piping encompassed by the clamp cannot be inspected. Visual inspections of the balance of the spargers in January 1980 revealed a number of additional cracks in the upper (System II) sparger. Because of these observations, additional visual inspections using improved TV camera support equipment and personnel were made and video taped. In addition, efforts were ini-tiated to develop and perform ultrasonic examinations of accessible (and some inaccessible) portions of the spargers. These additional inspections done in March 1980 showed that (1) the visual examinations by under-water TV can be improved significantly by the use of a special handling fixture which positions the camera a fixed distance from the sparger and permits slow con- , trolled movement of the camera during screening and TITLE i_ PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS
-Core Spray System Sparger Repair 6 0 3/31/80
(2) neveral UT techniques involving axial, circumfer-ential and helical wave transmission paths are feasible I and provide results which significantly improve the sensitivity and extent of the examinations. Accordingly, both UT and mechanically improved visual examinations l have been made of both the upper (System II) and lower (System I) core spray spargers. The indications re-l sulting from three independent visual inspectors and the UT examinations were evaluated and categorized by
- the criteria listed in Tabic 2. The indications meet- .
ing the criteria are classified as cracks and the re-sults are presented in Table 1 and Figures 3 and 5 according to the method of inspection and evaluation criteria which detected each crack. The ultrasonic examination methods referred to in Tables 1 and 2 are described in detail in Attachment l No. 1. In parallel with the inspections described above, additional evaluations and tests were performed to ! better characterize the observed cracks. These evalu-ations and tests are doncribed below. (a) Air Leak Tests Air leak tests were performed in the same manner i TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS
, Core Spray System Sparger Repair 7 0 3/31/80 j
J l 1 l i as in 1978. Air was introduced into the upper (System II) sparger until gas bubbles could be seen Icaking from the core spray nozzles under the j sparger indicating the sparger arms were filled with gas. Visual inspections showed no leakage 1 of gas through any of the cracks described above or from any other locations on the two upper spar-ger arms with the exception of the crack at 208' i j which was.found in 1978. This test indicates that { the cracks found in 1980 are not through-wall 4 cracks or they are very tight if through-wall. (b) Air Mockup Tests Mock-up tests to determine what size crack will pass air at a AP at a few inches of water have been performed. These tests show that crack sizes as small as 0.002 inches pass liberal quantities of air and demonstrate that the in-situ air tests are effective in locating n!gnificant sparger , cracks in the upper spargers. i (c) Visual Comparator Tests Tests were performed using a special visual com-parator to determine the resolution of the remote TV inspections. The comparator consists of a f series of different size wires which are lowered immediately in front of a sparger adjacent to an l TITLE PAGE REVISION NO. DATE Repair Proposal No. 47S-01 OCNGS Core Spray System Sparger nepair 8 0 3/31/80
l observed crack. These tests indicate that cracks less than 0.002 inches in width can be seen in visual examinations. They also provided a ba-sis for determining the width of observed cracks. (d) Review of 1978 Video Tapes In an attempt to determine if the additional cracks observed in 1980 are new since 1978, re-
- views were made of the video tape inspection re-cults from the Fall 1978 outage. Careful ex-amination of the video tape of the area at the sparger-to-inlet pipe junction at 152* shows that this crack was present in 1978. The fine appearance of this indication relative to that ,
at the 208' azimuth contributed to it being missed in 1978. Review of the tapes for other areas of the spargers indicates that the video tapes' clarity and focus are not as good as , those achieved during the 1980 outage and are j 1 not sufficient to identify the other hairline l cracks and crack-like indications which have ' l been found. As a result, it cannot be posi-tively determined from the 1978 inspection re-suits whether or not the cracks observed during ; l the 1980 outage were present in 1978. l TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 9 0 3/31/80
' On the basis of the above tests and examinations, it is concluded that only the original crack at 208 is sig-nificant in size. The rest of the observed cracks do not leak air and are estimated to be less than 0.002 inches wide on the surface.
j TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 10 0 3/31/80 i 1
4.0 EVALUATION OF CRACKING 4.1 Cause of Cracks It was previously concluded in 1978 that the crack observed at the 208* location was most likely in-itiated by stress corrosion attack and was propa-gated through-wall by bending type residual stress imposed during fabrication, fit-up and installation of the spargers into the shroud assembly with its many redundant supports. The additional cracks in the sparger are believed to be due to the same causes. Their appearance has the branching characteristic of stress cor-rosion cracks and their orientation is generally consistent with postulated residual bending stresses. Analyses performed since 1978 have
- shown that the residual stresses due to the tube rolling (bending) operation are significant.
These residual stresses are general in nature, and result in tension on the inner half of the sparger and compression on the side nearest the shroud with a variation across the sparger pipe section dependent upon the sparger unique fab-7 rication and installation history. This operation 1 TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 11 0 3/31/80 g Wu - g r - oqt 4- y-- =e-----w w -'t-
results in about 2% strain and residual stresses which are near the expected yield strength at operating temperature. Residual stresses due to loads applied during fit-up of the spargers to the shroud would be additive to the residual stresses due to tube bending and could change this residual strain pattern to some unknown ex-j tent depending on the direction and magnitude of the forces required to achieve fit-up. It is considered significant that the residual bending stresses which are considered to be the cause of crack propagation are self-relieving in nature. That is, the incidence and growth of cracking relieves the residual load which drives the cracks. They are also self-limiting, i.e., bending which could lead to significant crack opening is limited by the restraint provided by the shroud and sparger supports. Evaluation of loads on the spargers during normal opera-tion (including the Spring 1978 loss-of-feed I flow transient) has revealed no phenomena which would apply significant pressure, thermal flow impingement or vibratory loads on these spargers. TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 12 0 3/31/80
4.2 Future Operation - Structural _ Considerations i The adequacy of a core spray sparger with cracks for continued operation was evaluated in 1978 and again in 1980 by JCP&L, their consultants and General Electric. The conclusions of these evaluations are consistent and indicate the following: 4.2.1 Residual bending stresses due to tube rolling and bending moments applied dur-ing sparger installation together with some sensitization of the tube material due to welding, cold work, local heat-ing, etc., could conceivably cause the cracking that has been observed. How-ever, the nature of this loading is self-relieving and :ould not tend to pro-duce full 360 cracks. There is no known way in which net axial residual loads (which would tend to open full 360* cracks) could be imposed by the residual bending loads. 4.2.2 The spargers are subjected to no signifi-i cant loads during plant operation. Thus, l TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 13 0 3/31/80
there is no mechanism during normal operation which would tend to cause loss of sparger integrity or generation of loose parts. 4.2.3 The only event which applies any signifi-cant load on the spargers is injection of
, cool core spray water into'a sparger and shroud assembly which is at reactor operating temperature. Analyses indicate that this event produces two types of loading, as follows:
- Ilydraulic load - The actuation of core spray results in AP of less than 15 psi across the nozzles. This hydrostatic pressure results in a load of approxi-
-mately 150 pounds and a stress of 56 psi along the longitudinal axis of the sparger.
- Thermal mismatch - Injection of cold water results in a thermal mismatch between the core spray sparger which is-near injection water temperature and the core shroud which remains near the temperature of the fluid inside the TITLE PAGE REVISiCN NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 14 0 3/31/80
reactor vessel. [The skin thermal stresses due to introduction of cold l water are secondary and very , transient in nature and would not have a signifi-cant effect on crack propagation on a single injection). The thermal mis-match has two main effects on the sparger: (a) The free radius of the sparger would be smaller than the shroud, llowever, the sparger support brackets restrain the sparger radially so that it will stay at the same radius as the shroud. This results in radially outward loads on the sparger which produce bending in the sparger arms - tensile on the horizontal center- . line nearest the vessel center and compressive on the side near-est the shroud. (b) The length of the sparger becomes shorter. This' requires that the i sparger slide relative to the brackets which are holding it TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 15 0 3/31/80
radially outward to the shroud. The result is a frictional load at each bracket which is along the longitudinal axis of the sparger (i.e., the same as the load due to internal hydrostatic pressure). The total friction load is estimated to be about 1000 pounds, correspond-ing to a not axial stress in the sparger of less than 500 psi. The offect of these injection loads on a crack in the sparger has been analyzed assuming a crack which is through-wall 180* around the sparger, and located on the worst (tensile stress) side of the sparger nearest the vessel centerline. The only primary load on such a cracked sparger section is the axial load due to friction and 15 psi internal pressure, or about 1150 pounds. This load results in an average axial stress of less than 1000 psi in the intact half of the spar-ger tube. The bending due to thermal 1 mismatch is self-relieving (secondary) in nature in that flexure of the sparger TITLE PAGE - REVISION NO. DATE Repair Proposal No. 475-01 OCNGS
. Core Spray System Sparger Repair 16 0 3/31/80
at a crack would relieve the thermal mismatch and loads between the sparger and shroud. The amount of thermally in-duced bending is also limited since the sparger cannot bend beyond the ID of the shroud which it is pushed against. In this case, a through-wall crack 180 or more in length is calculated to open up less than 0.005 inches at the horizontal centerline. (If more than one crack were present in any span between supports, the amount of opening per crack is less than 0.005 inches.) The remaining in-tact cross-section of sparger adjacent to the core shroud would not be expected to fail since during a core spray actua-tion the thermally induced bending stresses in the outer half of the spar-ger are compressive and the net axial load is very low. In fact, the net axial load tending to separate the crack can be carried without failure by 10% of the circumference of the sparger cross-section (i.e., A crack TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 17 0 3/31/30
extending around 90% of the sparger cross-section would still not cause sparger failure during an inj,ection transient. Based on the above, it is concluded that neither the in-stallation nor original design-loads described above would be ex-pected to cause unacceptable cracking of the spargers, even with the ob-served or similar undetected cracks in the spargers. The potential for loads due to rapid steam condensa-tion (water hammer type loads) due - to steam-water interaction is a generic BWR question which is being evaluated by General Electric and the industry. I 6 TITLE
- PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS
- Core Spray System Sparger Repair 18 0 3/31/80
4.3 Future Operation (Ilydraulic Considerations) The function of the core spray sparger,is to distribute the core spray flow in a manner that ensures that each fuel bundle receives adequate flow. Tests performed during the original design of the system have shown that adequate distribution is obtained for system flows of 3100gpm to 4500gpm although the sys-tem design flow is 3400gpm at a reactor ves-sel pressure of 110 psi. The minimum flow rates (Technical Specification values) at the design point are 3400gpm and 3640gpm for - System I and System II, respectively. 4.3.1 Hydraulics analyses with bounding con-ditions were performed by General Electric to determine the effect of ob-served cracks on the System II cracked sparger flow distribution, including the effects of crack width increases of 0.005 inches as described above. The System II cracks as shown in Figure 5 were modeled based on actual opening plus .005 inch opening for initiation TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS ) Core Spray System Sparger Repair 19 0 ' 3/31/80
as through-wall 180* teardrop shaped cracks with a .006 inch horizontal centerline opening with the exception of 2.07* which has a horizontal opening of .037 inches, the 152* which has a horizontal opening of
.010 inches, the 165 which has a horizon-l tal component of 2" x .002", and the 264/
269' which has a horizontal component 1 1 of,4" x .002". As a basis for comparison, I I I the flow distribution along the sparger I arm was developed for the design condition l (3400gpm @ 110 psi) . The effects of flow through the assumed cracks was then ; added to the model,and new distributions
- along the sparger were developed as shown 1
below. o
$ 4500gpm a
N 3640gpm w/ cracks e-< -
,- 3400gpm base case z '
H I M / o 3100gpm 3 /
> /
= .
Distance Along Sparger TITLE PAGE . REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 20 0 3/31/80
The minimum individual nozzle flow was determined to be 104% of the 3400gpm base case value, which is acceptable, and which also provides margin to accommo-date additional small cracks of detection capability size. From these bounding analyses it is concluded that the current condition of the System II spargers will not significantly impact sparger flow distribution. 4.3.2 A bounding hydraulic analysis similar in type to 4.3.1 was performed for System I at 3400gpm with the five cracks as shown on Figure 3. The System I cracks were modeled hydraulically in the same manner . as the cracks in System II. The modeled horizontal opening was a function of actual crack size and additional opening i due to system initiation. As such, the System I cracks also have a .006 inch horizontal opening with the one exception of 251/255' which has an additional l l TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS - Core Spray System Sparger Repair 21 0 3/31/80
horizontal component which was modeled as a 3" x .002" rectangle. The results of the hydraulic analysis for System I show insignificant reduction (less than 1%) in the individual nozzle flows 4 below the 3400gpm baseline. Pressure drop calculations on this sytem show that more than 3400gpm is achieved at reactor pres-sure of 110 psi. This slight reduction in nozzle flow will not affect System I per-formance and the design nominal flow from 4 each nozzle in the system will be achieved. In all of these hydraulic analyses adequate conservatism is maintained because of the following: (1) All cracks are assumed to open to .005 inches tapered shape 180 long regard-less of their present size. In reality the cracks are tight and small. (2) All UT indications and all positive visual crack indications have been in-cluded as cracks. (3) In these bounding analyses all of the , crack flow area has been lumped on TITLE PAGE REVISiCN NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 22 0 3/31/80
the sparger near the junction box and this location has been shown by sensi-i tivity analyses to be the most limiting in terms of minimum individual nozzle flow. 4.3.3 The potential for adverse interference of flow emanating from a new or existing crack with normal nozzle flows was evaluated. Cracks of near zero width, assumed to increase in width by .005 inches as described above would have no adverse effect on System II spray dic-tribution because flow through such cracks could only add to the normal distribution (System II sparger is above System I and System II spargers have bottom mounted nozzles). Flow from new or existing cracks on System I could have a significant effect , on spray distribution depending on crack size and location. Based on crack width ; and conservative conservation of momentum principles, it was concluded that there l would be no adverse interference effect between crack flow and open elbow flow because open elbow flow overwhelms the TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray Syntem Sparger Repair 23 0 3/31/80 m - v m -- -
---n- , n .g. - - ,
postulated crack flow. From similar com-parisons of crack flow with 111!12 nozzle flow, it is concluded that no adverse im-pact would occur for crack widths of ap-proximately 0.005 inches. For those cracks not clamped on System I, they are not located near 111112 nozzles. Given the large total injected flow, it is difficult to believe
, that any crack flow (on the order of 1 gpm) could conceivably cause an adverse impact.
It is, therefore, concluded that spray interference from new or existing cracks on both System I and II does not present any significant risk. In evaluating the above analysis results, the follow-ing considerations should be kept in mind.
- The core spray System II can deliver a minimum of 3640gpm, which is 7% greater than the design basis flow of 3400gpm and 17% in excess of the minimum of 3100gpm determined to be required by test. Analyses of core spray System I show that it can also deliver considerably in excess of 3400gpm (at least as much as System II).
TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS , Core Spray System Sparger Repair 24 0 3/31/80
- Oyster Creek spray tests indicate that adequate bundle flows are achieved for spar-ger flows ranging from 3100 to 4500gpm, a vari-ation of -9% to +32% as compared to the design flow of 3400gpm.
- Variations in reactor pressure from the 110 psi assumed for evaluation of the core spray spargers' performance are significant. For example, the core spray actually starts at a reactor pressure of about 285 psi and continues as reactor pres- _
sure drops below 110 psi. The core spray flow in System II at a reactor pressure of 15 psi for ex-ample, would be about 4100gpm as compared to the expected flow of 3640gpm at 110 psi. These vari-ations in sparger flow due to reactor pressure changes during a postulated blowdown are signifi-
. cantly greater than the expected variations caused by small (e.g., 0.006 inch) cracks in the spargers.
- Not all LOCA breaks require spray for core cooling.
For most of the above core breaks and small below core breaks, the flooding capability of the core spray system is adequate for effective core cooling. TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNCS 4 Core Spray System Sparger Repair 25 0 3/31/80
- Specific analyses have shown that spray cooling is not required for the case where the core spray line break is the LOCA.
These considerations indicate that the existing cracks and the occurrence of a number of additional sparger cracks similar to those observed to date should have negligible effect on core spray effectiveness. I i J l r 1 i TITLE PAGE REVISION NO. DATE Repair Proposal No. 47S-01 OCNGS Core Spray System Sparger Itepair 26 0 3/31/80
5.0 CORRECTIVE ACTIONS 4 In order to provide additional structural margin, re-dundant mechanical supports are being installed at lo-cations where the number or location of cracks create concern about sparger integrity. The criteria used to locate these repair clamp assemblies are: 4 (1) Location where a helical UT indication is coinci-dont with a front visual or front UT indication at the sa'me azimuth. The simultaneous appearance of possible cracks on both the back and front or running around the bottom or top of the pipe raise concern about the potential for crack propagation, under system initiation loads, all the way around the pipe. The clamp provides resistance to such propagation and to crack opening should this ex-i tensive and unlikely cracking occur. (2) At the junction between the 5 inch inlet pipe and the sparger arms. These areas present an area of I concern because of the extensive cracking noted, the likelihood of a high degree of sensitization and the likelihood that the stresses in the sparger 1 are greatest in this location. Clamps strengthen the joints and resist separation of the components 1 should full circumference cracking occur. TITLE PAGE , REVISION NO. DATE Repair Proposal No. 475-01 OCNGS e
. Core Spray System Sparger Repair 27 0 3/31/80
The application of this criteria results in the addition
'of seven assemblies to System II and installation of clamp assemblies on System I (See Figures 6 and 7).
These mechanical supports consist of clamp assemblics as shown in Reference 7.1. These clamp assemblies are the same in concept, materials, and cross-section as the repair clamp installed at the 208 location in 1978. As described above, this clamp has performed satisfactorily in all respects since it was installed. The repair clamp assemblies shown in the aforementioned Reference 7.1 differ from the clamp installed in 1978 only in length and the fact that four of the clamps bridge around the 5 inch inlet junction boxes. As with the repair clamp successfully installed in , 1978, the new repair clamp assemblies are designed to carry the sparger design loads described in Section 4.0 above, and are positively engaged and locked around the spargers to preclude their becoming loose parts. In addition to the above, engineering design work has been initiated to develop an improved core spray system and/or sparger for installation at a future outage. Further, JCP&L plans to inspect the core spray spargers and clamp assemblics at the next refueling outage. ! 5 TITLE PAGE REVISION NO. DATE l Repair Proposal No. 475-01 OCNGS
- Core Spray System Sparger Repair 28 0 3/31/80
6.0 SAFETY EVALUATION The core spray systems at Oyster Creek Nuclear Generating Station are the primary means of Emergency Core Cooling in the Event of a Loss of Coolant Accident even if there is a simultaneous loss of off-site electrical power. The capability of these systems is analyzed and pre-sented in docketed LOCA analyses. A failure modes and effects analysis of the Oyster Creek ECCS done in 1975 resulted in a modification to the core spray systems (Reference 7.2) which assures the operability of both of the systems even under the as-sumption of a single failure in each system. Conse-quently, 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. In-dependent 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 re-flooding the reactor vessel and keeping the reactor core cool. LOCA analyses assume no credit for core spray cooling of the fuel bundles until the rated flow of 3400gpm TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 29 0 3/31/80
is achieved at a reactor pressure of 110 psi. Only "after reactor pressure is reduced by blowdown or Auto- , matic Depressurization System (ADS) operation to 110 psi or below, is a flow of 3400gpm assumed even though actual flow would commence at a pressure of 285 psi and in-crease as reactor pressure is decreased. This is one of several conservative assumptions in the ECCS analysis and in the plant design. The safety objectives of this repair are: (1) to demon-strate 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 as-sures adequate flow to each fuel bundle; and (2) to demonstrate that existing cracks and.possible future cracks are not likely to result in loose parts in the reactor vessel. This demonstration of adeqtiate flow has been accomplished by evaluation of the effect of (1) the existing cracks in System II spargers and (2) the existing cracks in System I spargers. The results of the bounding analyses are presented in Section 4.3 above, and show that the TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 30 0 3/31/80
core spray flow and distribution will be sufficient to assure adequate flow to each fuel bundle. The demonstration that loose parts will not be de-veloped is covered in the discussion of the structural uapability of the sparger discussed in Section 4.2, above. It includes evaluations of known and postulated cracks and concludes that for all design loads, the sparger has sufficient strength to remain intact even in the presence of significant cracks. Therefore, no loose parts would be expected. To provide additional structural margin in the presence of s'ignificant cracking (See Criteria in Section 5.0 above), the repair clamp assem-blies are being installed in the nine locations discussed . in Section 5.0. Based on the above considerations, the following con-clusions can be drawn: (1) Numerous indications have been detected to date on both system spargers. Twenty-nine of these indica-tions have been classified as cracks. (Twenty-four on System II and five on System I.) (2) It is very unlikely that any significant indications have been missed. (3) Extensive additional cracking is not likely in the next cycle of operation. TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS Core Spray System Sparger Repair 31 0 3/31/80 v - -, --,7
(4) Existing cracks and new cracks, should there be any, are not likely to propagate or open very much during normal plant operation. (5) The only significant operational load's that can be postulated are those associated with initiation of the core spray system and even under these loads, significant crack initiation or growth is not expected. (6) For reasonable assumptions on the existing crack size and propagation, analyses demonstrate that the design nominal flow and distribution character-istics of the core spray system can be maintained within acceptable limits. Margin remains for new cracks. (7) The clamp assemblies at all significant crack lo-cations provide additional structural capability to the sparger and minimize the chances for geometry cf'.nges significant to the hydraulic per-formance. (8) Crack flow is unlikely to significant1: affect the spray distribution. (9) Although this repair does not restore the core spray sparger to its original design condition, there is reasonable assurance that in the unlikely event the core spray system would be called upon to' function l TITLE PAGE REVISION NO. DATE , R'epair Proposal No. 475-01 OCNGS
)
-Core Spray System Sparger Repair 32 0 3/31/80 l i 1
during operation, the system including the spargers would perform its intended function in accordance with the original design criteria. (10) The next cycle or two will be used to develop and install an improved system or sparger to provide even greater long-term assurance of operability. 1 TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS
- Core Spray System Sparger Repair 33 0 3/31/80
7.0 REFERENCES
7.1 MPR Drawings 1083-12-06, 1083-12-08, 1083-12-09, 1083-12-10, 1083-12-11,.1083-12-12 7.2 Jersey Central Power & Light Company, ECCS Modifica-tion Core Spray Electrical Crossconnect, Oyster Creek Nuclear Generating Station, Docket 50-219, Attachment II, Revision 1, July 15, 1975 1 i I TITLE PAGE REVISION NO. DATE Repair Proposal No. 475-01 OCNGS
. Core Spray System Sparger Repair '34 0 3/31/80
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ATTACHMEllT I -
SUMMARY
OF RESULTS FROM UT ItiSPECTI0 tis This report represents the results of the ultrasonic examination performed on the Core Spray Sparger Systems I and II. The examination process is comprised of six inspection. efforts from January 20, 1980 through March 18, 1980. The purpose of this examination effort was to inspect the highest volume of sparger pipe possible in a relatively short amount of time. The goal was to maximize the probability of locating relevant ultrasonic indications while not reporting superflous nicks, gouges, or nonrelevant anomalies. These constraints resulted in certain limitations on the sophistication of the scanning device utilized, on the available areas of the pipe to be scanned, on the state of the art technology to be used and the ultrasonic sensitivity threshold to which the ultrasonic system was calibrated. _ The scanning device utilized was comprised of a main body or truck and two arms. Each arm holds two fixtures; one for the upper sparger and one for the 1ower sparger, making a total of four ultrasonic fixture pads (See Figure 1). There are two distinctly different sets of fixture pads which can be utilized. The first set (GI) has two different transducer arrangements per pad. One I arrangement is comprised of two transducers; one incated at the top.'and 'one at the bottom of the pad. This arrangement scans circumferentially and utilizes loss of signal as an indicator of an indication. The observed area of scan may be either 480 or concentrate only on the 120 of the sparger front face. The other transducer arrangement is comprised of two transducers. They are located on the left and right side of the pad and scan' longitudinally, utilizing standard pulse-echo techniques. These transducers scan outward away from the pad and only observe reflectors that cross the sparger ID center line of the pipe. The limitations of the longitudinally scanning arrangement is that circumferential1y oriented reflectors will not be observed unless they cross the sparger ID center
- iPage X a line. The limitation on the circumferential 480* scan mode is that it will not scan areas obstructed by the nozzles (See Figure 2).
The second group (G II) also has two transducer arrangements. These transducers scan in a helical pattern, utilizing loss of sound as an indicator of an indication. The transducers are located at each of the four corners of
- thc pad. The upper left transducer transmits over the topfof the pipe heading in a spiral to the right. The sound crosses over on the back side of the pipe and is received after going through the bottom of the pipe by the lower right transducer. This is nominally a 240 scan of the front, top, back, and lower front portion of the pipe. The opposite is true of the second transducer pair -
in this group. The upper right transducer transmits to the lower left transducer by travel through the back side of the pipe (See Figure 3). The limitation for the helical scan is that when scanning in a given direction, the lead transmitting transducer will be obstructed when the nozzles are in the path of sound travel. The trailing transmitting transducer will also be obstructed when the nozzle is obstructing its sound transmission. It should be noted that the lead and trailing transmitting transducers are three and one half inches apart. The nozzles are approximately four to five inches apart. Therefore, nozzle obstructions will cause loss .of sound in only one transmitting / receiving pair at a time. In consideration of this occurrence, procedural criteria were established to require that both transducer pairs would have to lose sound before an indication would be recorded as relevant. This would indicate a reflector large enough to cross both helical scans in either the horizontal or vertical axis, or a reflector that is oriented in a ashion to intersect one scan while the other scan was obstructed by a nozzle. Both cases would show a simultaneous loss of sound. The limitation e s that indications which did not cross both sound paths or did not occur coinci-dentally with a nozzle obstruction in the other transducer pair would go unrecorded. i
. _- . - - . . _ . . =-- . _. --
Page 3 l The combination of both Groups I and II give a longitudinal scan left and right on the sparger ID center line; a nominal 480' circumfer'ntial scan of front and back; a nominal 120 front face scan; and a 240 nominal helical scan of back. Accessible areas scanned with a combination of the modes mentioned above had approximately 90% coverage (See Figure 4). In addition to the scanning limitations in accessible areas, there were i i physical obstructions that prevented access and scanning of the pipe. The shroud lip had 16 gussets, the piping was held in place by 12 brackets per system,
- the upper core area had four locations of hold down clips, guide pins and eye i
bolts and the close proximity of these obstructions relative to each other all created areas not accessible to scanning (See Figure 5 and Attachment 2). , Approximately 35% of the sparger circumference was not scanned due to these obstructions. When scanning limitations are combined with physical obstructions, it is estimated that 58% of the pipe area was ultrasonically examined.
; State of the art technology precluded the use of multiple scanning and concurrent analysis via an electronic device. The test effort was limited to mechanically switching from one channel to another, llowever, readily available
- audio alarms were utilized. The use of audio alarms was employed to assure that i when an indication reached or exceeded a certain threshold of sensitivity, there would be certainty in observing it. In all cases, the ultrasonic system was set i up to alarm at 50% through wall notches and to igiiore indications which were less i
than 25% through wall notch responses. A minimum of 25% notch response required prior to taking notice, assured that superflous nicks, gouges, and material anomalies would be disregarded. Ilowever, this built in the possibility of ignoring very shallow (less than 25%) indications that may be relevant. ! Generally, all recorded indications were not recorded until after enrtain prerequisites were met and technique checks were made. Details of these relevancy tests may be found in the detailed report dated March 17, 1980.
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W n i In conclusion, certain comments may be made concerning the 16 locations of reflectors found by all .three major examination efforts. See Attachment 1 for reference to the following items:
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- 1. 5" - Detection by helical scan only indicates the reflector is not within the 120* front surface scan which also means it is not across the sparger ID center line. The reflector could be anywhere else on the sparger circumference. Possible explanations for not detecting the reflector with the 480 scan include; a lower degree of scan detectability of the 480* scan or scanning obstructions caused by the nozzles.
- 2. 13/14* - See Item 1,
- 3. 22/23 both 120 front surface and helical scan detection indicates that either two indications exist at the same azimuth or a single indication extends across the front face into the area at the top or bottom of the sparger, flo conclusion can be drawn as to whether the reflector extends onto the back side.
- 4. 102/103' - 120 front scan detection only indicates a front face location. Lack of 480* scan detection indicates that it could be in line with a nozzle obstraction or the 480* scan detectability is lower thca the 120 scan. .
E. 148 - See Item 4.
- 6. 150* - Longitudinal and 480 scan detection indicates circumferential orientation with significant off-planer componets. Lack of detection by 120* and helical scan indicates a physical obstruction preventing placement directly over this retiector.
- 7. 165/170* - Longitudinal and 120 scan detection indicates a front face location with dual axis orientation.
- 8. 183/185* - See Item 7.
, 9. 189* - See Item 4.
~ Page 5
- 10. 192/195* - See Item 3
- 11. 220/225' - See Item 4.
- 12. 264/269* - See Item 3.
- 13. 305/307* - See Item 3
- 14. 322* - See Item 4.
- 15. 335/341* - See Item 3.
- 16. 360* - See Item 1.
NOTE: The numbers 120*, 480*, and 240* are nominal values. These nominal values have been utilized throughout the entire examination effort. The actual figures are as follows: 120* = 142* 240 = 270 480* = 502 The actual numbers may be substituted for their nominal figures when found in the reports. CONCLUSION ' A philosophy of conservatism was practiced throughout the examination efforts . An indication was not recorded unit s: 1) a significant threshold sensitivity was exceeded; 2) repeatability was used to conform it; 3) various confidence methods were employed to determine relevancy; and 4) careful comparison to obstructions was made. Indications may have been missed due to: 1) reficctor l size being below the calibrated sensitivity level; 2) indications were located l in areas unscanned; or, 3) the various confirmation techniques did not conclu- l sively prove relevancy. As a result of the identified deficiencies, detection of all possiale indications cannot be assured. On the contrary, there is a high degree of confidence in the existence and relevancy of the identified indications. O l-
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O PlVE Q 5 BRACKETS \ af-QPERM$ g oto g g , gg, gyg fofp" PtFI OoLT Nt/ 4@ OBSTRUCTIONS FIGURE 5
FINAL ATTACHMENT I DETECTED BY DETECTED BY , 11IIT!!CT!!D BY DETiiCTliD BY DETECTED AZi?!!Tril DATE LO JGITUDINAL 480 120" !!Ei.ICAL~ VISUAI I.Y _ _ _ _ _ _ _ _ _ _ . . _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ . . _ CI.RC@ffiB.E. NTMI. ;1RCDIEliREffLLAL
/ 5 3/18/80 No . No No Yes .
13/14 0 3/18/80 No 7 No No Yes 3 22/230 3/13/80 No No Yes Yes 3/18/80 y 102/1030 3/13/80 No No Yes No f 1480 3/13/80 No No Yes No 6 150 0 3/2/80 Yes Yes No No 3/13/80 1650/1700 - 3/13/80 Yes No Yes No 1- 1830/1850 3/2/80 Yes No Yes No 1890 3/13/80 No No Yes No 3/13/80
/0 192/195 3/18/80 No No Yes Yes .
O 220/225 0 3/13/80 No No Yes No 3/13/80 [2 .264/2690 3/18/80 No No . Yes Yes 9 3 / 19
, , MWA
l' age 2 of 2 ATTACHMENT I DliTEC111D BY DETECTED BY DETECTED BY DETECrl!D BY DETliCTliD AZlHillli DATE LONGITUDINAL 4800 120 IIELICAL VISUAI.I.Y
'T RCINFERENTlAL CIECUEEERENTIM
/3 305/3070 3/13/80 No No Yes Yes 3/18/80 ,
/y 3220 3/13/80 No No . Yes No jg 335/341 3/13/80 No No Yes Yes 3/18/80 360 0 3/18/80 No No No Yes ,
e e --e e G - O N O e
# a O
h 3/19/s
..: d
UT OF SPARGER - UN5 CANNED AREAS DATE 3-2-80 3-13-80 3-18-80 TYPE UT , LGC 480 C 120 Helical Lower Upper G Lower Only OBSTRUCTI ON Head 150-161 Bracket 172-186 175-180 174-180 195-198 Bracket / Clip / Pin 200-215 200-216 202-215
, Arm End 220-228 224-228 225-255 Arm End 234-245 232-236 240-250 Bracket 265-280 269-274 269-290 Bragket/ Clip 300-315 292-303 300-304 312-317 316-330 Header 340-345 330-335 -
Bracket 355-10 356-360 359-360 Bracket / Clip / Pin 30-40 20-34 28-38
. 45-58 43-47 56-58 Arm End 56-67 60-70 64-68 Arm End 70-80 72-79 Bracket 86-102 90-94 90-94 104-110 Bracket / Clip / Pin 120-130 112-135 118-122 .
127-133 liead 135-150 I 3/25/80 MWA
Page 1 of 3 TABLE 1 -
SUMMARY
OF VISUAL & ULTRASONIC Q AMINATION RESULTS , CORE SPRAY SYSTEM II DETECTED BY ~ DETECTED BY CRITERIA #1 AZIMUTH LONGITUDINAL " ^ E L - 5 NO NO NO YES YES 13/14 NO NO NO YES NO 22/23 NO NO YES YES NO 102/103 NO NO YES NO NO 112 NO NO NO NO YES 146 NO NO NO NO YES 148 NO NO YES NO YES 152' YES YES NO NO YES 155 NO NO NO NO YES 165' YES NO YES NO YES 183&l85' YES NO YES NO YES 189 NO NO YES NO NO 192&l95* NO NO YES YES YES 220 NO NO YES NO NO 264/269' NO NO YES YES YES 305/307' NO NO YES YES NO 322 NO NO . YES NO NO ' 328* NO NO NO NO YES
3 1 f o A I S S S S S 2 R E E E E E E Y Y Y Y Y e T^ g I a R - P C S T L Y U B S E D^ R E T O O O O O N C N N N N N O E I T" T E A D N I M A _. _ X E Y B L C Ti I D N I E O T O O O O O S M C E N N N N N A E E R R T T . T S E L Y D U S
& Y A
L R ~ A P Y U S B S I E D V R E O O O O O O T N N N N N F C C 7 O E T Y E R D4 A M M U S Y L B A N _ D ID _ E U _ T T 1 C I O O O O O _ E G N N N N N E T N . L - E O B D L A T 5 H 5 T 2 U - M 8 1 6 1 8 I 4 5 5 5 2 Z 1 1 1 2 3 A
)
is! -
, 7
- s i ^ t e ,
)
S 1K 3 #C _ A f AR o IC R S . 3 EL E O O _ TA Y N N e IU g RS a CI P V ( S T . . L Y
. U B S L ^
E DA R EC S S TI O E E N CL N Y Y - O EE I TH T E . ._ A D .- N I M A X - E YM . BUL C CA I I DRI _. N I EIT S O - TCN O E O S M C E N Y N A E E' R R T T0E _ T S E2F L Y D1 U S - _ & Y . A L R - A P YM . U S BUL S CA I E DRI V R EIT O TCN O O O F C C E N N N O E' R T0E Y E8F ._ R D4 A M M _ _ U S Y L BA N
- D ID E U T T 1 C I O O O
._ E G N N N - E T . L E N B DO L - A T 8 3 H 3 T ' /
- U 1 5 0 M 3 3 6 I 3 3 3
. Z _ A 7
. :l ' 1 I1 J I k i
!)
i i TABLE 2 t ! CRITERIA FOR CLASSIFYING INDICATIONS AS CRACKS .i l 1. Positive visual
- plus any possible visual
- l :
Rocctd if a) within 120* on front or at top or bottom I l' b). UT was active at that point ; i < i > l '. 2. Any helical UT indication:
. Record if a) coincidental with any visual'at top or bottom ' ; b) coincidental with 120* UT or any visual within 6
120* front face . I i
- 3. A 120* UT (front UT) or longitudinal UT indication plus any
! visual indication I i i J }. 1 Positive Visual = Visual examiner's statement that "this is a crack" or "positivo crack" or " identified j crack" Possible-Visual = " faint", "possible" , "li ne" , "maybe" cracks or-indications . +
.e,.w. , - - - . .- -.}}