ML070670462

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Job Order 98-0113, ASME XI, IWE Miscellaneous Information, 02/06/1998
ML070670462
Person / Time
Site: Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date: 02/06/1998
From: Larsen C
Duke Engineering & Services
To:
Office of Nuclear Reactor Regulation
References
Job Code 98-0113
Download: ML070670462 (23)
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Text

JOB ORDER FILE 98-0113 MISCELLANEOUS INFORMATION VII. ASME XI IWE Miscellaneous Information I

1 MEMORANDUM -

i DUKE mGINEERJNG AM) SERVICES BOLTON -

To J. A. Schaefer Group# PSD 41/98 Fhom C. B. Larsen - W.O.# 4903

- Sabjed PROPOSED STRATEGY FOR DlSPOSlTlON Ll&Sd#

FBe# IWESTRAT.TOR OF ASME XI, IWE. FINDINGS IN TORUS I .

REFERENCES

1) Memorandum E. J. Betti to E. Lindamood, dated December 19, 1997, "Scope Memorandum for the RHR and CS Strainer Replacement EDCR 97-423
2) Specification WS-049, Revision 2
3) 10CFRb0.55a
4) Memorandum C. B. Larsen to E. J. Betti, dated January 5, 1998, "Nondestructive Examination Requirements for 1998 Torus Work"
5) ASME Section XI, 1992 Edition with the 1992 Addenda 61 ASME Section 111, Subsections NE, 1992 Edition with the 1992 Addenda DISCUSSION Reference (2) specification and EDCR will define the requirements for purchase of suction strainers to be installed in the torus in response to NRC Bulletin 96-03.

An as-found examination in accordance with ASME Section XI, lWE-2500(b) and

... Table IWE-2500-1, Categories E-A and E-C, will need to be performed prior to removing coating on both the inside and outside surfaces. This applies to all areas that are going to be recoated, but especially to the areas covered by the modification. The components within the scope of IWE that are being repaired in the 1998 refuel outage are the torus shell interior below the water line, the torus shell exterior at the temporary access hole water level instrument penetrations, the vent header interior, and the torus downcomer interior and exterior beiow the water line.

ASME Section XI, IWE-1241, requires augmented examination in accordance with Category E-C for areas that are likely to experience accelerated degradation and aging. This would apply t o the torus interior below the water line. It would also apply to the torus vent header. IW-2500(c) stipulates that the examination methods for augmented examinations will be VT-1 if both surfaces are accessible.

Surface areas accessible only from one side shall be examined for wall thinning using an ultrasonic thickness measurement method.

A It would depend on the desire to perform examination of this area while it is easily ccessible, or to wait until a later outage.

Examinations on Coated Areas." It states that the area shall be examined for evidence of flaking, blistering, peeling, discotoration, and other signs of distress.

Areas that are suspect shall be accepted by engineering evaluation or corrected by repair or replacement in accordance with IWE-3522. It is expected that an evaluation in accordance with IWE-3122.4 will be necessary because of coating degradation that has been identified in the torus. under previous inspection programs. Evidence of coating degradation itself may be repaired by recoating.

However, the pressure boundary in those degraded areas must be assured to be within design specifications. The design minimum wall thickness for the torus bottom plates-is 0,584", which is not much below the supplied plate thickness.

Therefore, a wall thickness verification program will almost certainly be necessary.

The following strategy describes a method of performing this required analysis on the torus shell.

1) Following torus drain-down and drying, perform a visual exam coating removal. Map out areas of flaking blistering, peeling, discoloration, etc. Locate the center of the degraded areas from the ring girders and bottom dead center or other coordinate system (eg. the welds if they are

._.. visible) and record the approximate size of the degradation. Classify the degradation into types (eg. flaking, general rusted areas, damaged areas, pitting, etc.). Take Polaroid pictures and label the pictures with the bay numbers and plate numbers.

2) Assemble the initial inspection reports and divid types into groups. Determine from a sampling table the aporopriate sample size for each degradationtype that would be required for further evaluation.

Select the areas from each degradation type to be examined. This selection could be random, based on construction schedule and ease of testing, or just

' kT Ihlq!K

3. A. Schaefer comtvq- BY February 6, 199 performed. It is recommended that a step wedge be coated on the bottom with a similar paint and the readings from both surfaces compared. It is also recommended that the torus be checked in several areas to determine if small pits, i.e. that a back
6) Perform and record UT thickness measurements from the OD in the selected areas.
7) Following coating removal by shot blasting, re-perform a visual examination, particularly in the areas recorded in Step 11, to identify any visibly thinned areas. The dimensions from the reports in Step 1) can be used to relocate those areas in the downcomers. Add any visibly thinned areas t o the areas in those areas on both the inside and outside surfaces.

In addition, the torus downcomers will also be stripped of paint in the areas below the water line. The following strategy would apply to the torus downcomers.

1) Perform a visual examination of the ID and OD of the torus downcomers from six inches above the water line to seven inches above'the bottom end of the downcomer prior to coating removal. (The bottom seven inches of each downcomer will be removed later and will not need to be inspected.)

Map out areas of flaking, blistering, peeling, discoloration, etc. Locate the center of the degraded areas (from the bottom of the downcomers and using the azimuth around the downcomer. Record the approximate size of each area of degradation. Take Polaroid pictures and label the pictures with the downcomer number.

2) Following coating removal, re-perform a visual examination, particularly in the areas recorded in Step 11, to identify any visibly thinned areas. The dimensions from the reports in Step 1) can be used to relocate those areas

J. A. Schaefer February 6, 1998 Page 4 in the downcomers. A program to ultrasonically measure thicknesses in areas noted in Step 1) as will be done for the torus shell is not necessary, unless there are visibly thinned areas. This is because there is more design margin in the torus downcomers than in the torus shell, and a visual examination will be sufficient to identify thinning that would be close to the downcomer minimum design wall thickness. ,. -

3) Perform ultrasonic thickness measurements of the visibly thinned areas. It may be necessary to transfer the locations to the opposite side of the material thickness (ID to OD or OD to ID) to achieve proper results if the thinned area surfaces are rough and/or piked.
4) Forward the thickness measurements from Step 31 to engineering for disposition. The measurement data will need to be sufficient to plug into the engineering acceptance formula.
5) Performa Category E-A preservice (baseline)examination following recoating in those areas on both the inside and outside surfaces.

In the meantime, the Vermont Yankee will also be performing coating repairs of the vent header interior. The following is a recommended approach for that work.

The vent header coating will be stripped and/or scraped in areas that were peeled, blistered or damaged and then readied for coating reapplication. At that time, it would be advantageous to perform UT thickness measurements in those areas. if any of those thickness measurements are found to be below minimum wall thickness, report those locations and thicknesses to engineering for disposition.

It is expected that DE&S, Vermont Yankee personnel and GTS personnel will perform the visual portion of the inspection. The painting contractor, Williams Power Corp., also has QC personnel that are qualified for coating inspection that may be available for this task. With the possible exception of Williams Power Corp., in general, the personnel will already have been certified Lbvel I1 for visual testing. In addition, a minimal amount of training will be required to upgrade the

\ necessary for this job will need to be determined.

J. A. Schaefer February 6, 1998 Page 5 If you have any questions concerning this input, please call me at extension 2091 in Bolton.

c Carl LarseX, ISI Level IIC.-

Technical Services c: E. J. Betti J. F. Calchera - W J. H. Callaghan P. B. Corbett - VY M. Dugan - W D. C. Girroir - VY S. D. Goodwin J. R. Hoffman

v. lyer -ANII V. Langley J. J. McCann - PSD R. M. Mitchell P. A. Oikfe E. Taintor W-S. J. Volk

From: John Schaefer (CVAX:SCHAEFER)

To : CALCHERA, GIRROIR-D Date: March 10, 1998, (Tuesday) 1:35pm

Subject:

IWE/TORUS PROJECT MEETING (3/10)

JIM AND DENNIS,

- THE PURPOSE OF THIS MEMO IS TO PROVIDE A

SUMMARY

OF THE SUBJECT MEETING.

THREE OPEN ITEMS IN ORDER OF IMPORTANCE HAVE BEEN IDENTIFIED THAT NEED FURT"R ATTENTION: .-

1. ACCEPTANCE CRITERIA ANALYSIS - DESIGN ENGINEERING IS BELIEVED TO HAVE THE llBALL" ON THIS TOPIC. WE MAY NEED TO STRESS SIGNIFICANCE ON THE IMPACT TO THE INSTALLATION THIS EVALUATION HAS SUCH THAT THEIR PRIORITIES CAN BE READJUSTED.
2. BASE METAL EXAM CORDINATION - IS1 GROUP AND TORUS PROJECT GROUP HAVE THE BALL ON THIS TOPIC. A SECOND MEETING IS GOING TO TAKE PLACE BETWEEN (MPM, JFC, DH, JAS, DB) TO RESOLVE AND CORDINATE.
3. EXAM COVERAGE FOR THE FOLLOWING COMPONENTS - DOWNCOMERS, AND WNTHEADERS.

DCG AND I WILL DECIDE ON THIS 3/12/98 AND LET YOU KNOW ASAP. SEE BELOW IN "ITEMS NOT DISCUSSED #IS 1-3.

OTHER TOPICS DISCLJSSED:

1. AS FOUND IWE EXAM WORK FLOW - WE PLAN TO HAVE THE EXAMINERS FOLLOW THE "DECON" WORKERS AND EXAMINE THE BOTTOM MOST PORTION OF THE TORUS - PAYING PARTICULAR ATTENTION TO THE "SCAFFOLD" RING AREAS. SUBSEQUENTLY, WPS WILL INSTALL THEIR SCAFFOLDING - INWHICH THE EXAMINERS WILL MAKE A SECOND PASS (EXAMINING FROM THE SCAFFOLD UPTO THE BLAST LINE).
2. THE IS1 GROUP WILL SUPPLY THEIR OWN LIGHTING FOR THE AS FOUND EXAMS. WE HAVE AN INTERST IN UTILIZING WPS LIGHTING DURING THE OTHER TO EXAMS. THE 500 W LIGHTS SHOULD PROVIDE SUFFICENT LIGHTING DEPENDING UPON THE DUST AND PARTICULATES IN THE AIR.
3. AREAS INDENTIFIED AS RECORDABLE WILL BE UT'D FROM THE OUTSIDE OF THE TORUS.

OTHERWISE THE DESIGN ENG. ACCEPTANCE CRITERIA WILL BE APPLIED "ON THE SPOT" BY THE LEVEL 11's TO DETERMINE IF AN AREA IS ACCEPTABLE OR UNACCEPTABLE. AREAS REQUIRING FURTHUR EVALUATION WILL BE TAPED OFF SUCH THAT RECOATING WILL NOT RENDER THEM "INVISIBLE" TO FIND. THE ADDITIONAL EVALUATION WILL INCLUDE UT'S.

4. ALL EXAMINERS WILL BE RESPIRATOR AND LEAD QUALIFIED. THUS, WORK SCOPE PERMITTING, THE EXAMINERS CAN WORK SIDE BY SIDE WITH THE CRAFT (IE DOWNCOMER SNIPPING, BLAST CLEAN-UP, ETC) .

TOPICS NOT DISCUSSED:

1. NO EFFORTS WILL BE PLANNED TO EXAMINE THE TOP INTERIOR HALF OF THE TORUS.

HOWEWER, IF EXAMINERS SEE/IDENTIFY AREAS THAT DO NOT MEET VT-1 ACCEPTANCE CRITERIA, SUBSEQUENT EXAMS AND EVALUATION WILL PROCEED IN ACCORDANCE WITH THE CODE.

2. THE EXAM COVERAGE FOR THE DOWNCOMERS WILL INCLUDE THE ENTIRE VERTICAL PORTIONS INSIDE AND OUT. REMOTE TOOLS MAYBE REQUIRED AND UTILIZED IN ACCOF!DANCE WITH SECTION XI. THE ANGLE PORTIONS OF THE DOWNCOMERS ARE STILL BEING CONSIDERED FOR EXAMINATION - HOWEVER, GIVEN THE TIGHT WINDOW OF OPPORTUNITY AND THE FACT THAT THESE CAN BE EXAMINED IN FUTURE OUTAGES WE WILL PROBABLY NOT EXAMINE THEM.
3. VENT HEADER EXAM COVERAGE - PER THE CODE WE WILL BE REQUIRED TO PERFORM VT-1 ON THE REPAIR AREAS. NO PLANS WILL BE MADE TO LOOK AT THE EXTERIOR OR OTHER INTERIOR SURFACES FOR THE SAME REASON EXPRESSED IN # 2 ABOVE. HOWEVER, IF

THE EXAMINERS FIND A R W THAT ARE DEGRADED, EXAMS WILL HAVE TO BE PERFORMED AND EVALUATED FOR THE SAME REASON DISCUSSED IN #1 ABOVE.

FOR # ' 1-3 IT IS NOT IMPARATIVE THAT WE PERFORM VT'S ON THESE AREAS DURING THIS OUTAGE, SINCE UT'S CAN BE PERFORMED DURING SUBSEQUENT OUTAGES WHEN LESS ACTIVITY IS TAKING PLACE IN THE TORUS.

CONTINGENCY PLANS W WOULD BE WISE TO HAVE PEOPLE QUALIFIED TO PERFORM SURFACE REPAIRS (IE WELDERS) IN THE EVENT THAT AREAS ARE FOUND TO BE BELOW THE MI?? WALL THICKNESS DETERMINED IN THE EVALUATION.

WPS WILL BE UTILIZED TO AID WITH ALL THREE EXAMS ON AN AS NEEDED BASIS. THE ISI GROUP w r u RELY ON THE TORUS PROJECT STAFF (JFC/DH) TO GIVE THE GREEN LIGHT ON WHEN THE EXAMINERS ARE FREE TO PERFORM THEIR WORK.

NO ADDITIONAL STAGING REQUIREMENTS ARE FORESEEN AT THIS TIME. THE IS1 GROUP PLANS TO WORK OFF THE "BLAST" STAGGING THAT GOES CIRCUMF. AROUND THE TORUS.

PLEASE LET ME KNOW IF YOU HAVE ANY OTHER QUESTIONS.

JOHN cc : D u m , TAINOTR, LARSEN, TODD

From: John Schaefer (CVAX:SCHAEFER)

To: CALCHERA, GIRROIR-D, HUMBERT, DUGAN, TAINTOR Date : March 11, 1998, (Wednesday) 2:07pm subject: IWE SCOPE JIM, DENNIS (GIRROIR) AND MYSELF DISCUSSED THE EXTENT OF IWE COVERAGE PERTAINING To

< THE STRAINER PROJECT. THE PRIORITIES STAND AS FOLLOWS: BOTTOM HALF OF THE TORUS INTERIOR BELLY (ALL BAYS), VERTICAL SEGMENTS OF TKE DOWNCOMERS (INT AND EXT), AND VENT HEADER REPAIR AREAS. LIKE I SAID PREVIOSLY, THE SCOPE CAN EASILY EXPAND IF THE EXAMINERS SEE COMPONENTS THAT APPEAR SUSPECT ON THEIR WAY TO THE EXAM LOCATION.

DATA SHEETS HAVE BEEN MADE TO AID WITH ID OF THE AREAS AND LOCATIONING AREAS WHICH SHOULD BE UT'D. WE ARE DEVELOPING A CHECKLIST/SIG-OFF LIST OF THE PRIORITY COMPONENTS. SHOULD WE GET INTO A SITUATION THAT WE CAN EXAMINE THE ITEMS DISCUSSED BELOW - A SEPARTE TRACKING SHEET CAN BE DEVELOPED BASED ON THE REQUIRED DATA SHEET.

IF THE SCHEDULE PERMITS WE WILL TRY TO KNOCK OUT THE UPPER HALF OF THE TORUS INTERIOR BELLY, EXTERIOR OF THE VENT HEADERS, THE UN-EXAMINED PORTIONS OF THE VENT HEADER INTERIOR, AND THE REMAINING PORTIONS OF THE DOWNCOMERS. THE VENT PIPES WOULD ALSO BE CONSIDERED AS WELL. AGAIN THIS WILL ONLY BE PERFORMED IF THE SCHEDULE PERMITS.

PLEASE LET ME KNOW IF YOU SHOULD HAW ANY OTHER CONCERNS PERTAINING TO Im.

JOHN

AGENDA IWE MEETING 3/18/1998 A. AS FOUND EXAM PROCESS AND STRATEGY

1. PROCESS
a. DRAINDOWN
b. WIPE DOWN AND LIGHTING MSTALATION
c. IWE LOWER BELLY @ELOW SCAFFOLD LINE) AND DOWNCOMERS
d. WPS INSTALL SCAFFOLD
e. IWE UPPER BELLY (ABOVE SCAFFOLD LINE) AND VENT HEADER REPMRAREAS
f. TURN TORUS OVER TO WPS
2. STRATEGY
a. UTBEFORE,OR
b. UTAFTER
3. BASE METAL E X A M PROCESS AND STRATEGY
1. PROCESS a WPS PREP FOR BLASTING
b. WPS BLAST 8 BAYS
c. IWEEXAMS8BAYS
d. WPS BLAST 8 BAYS
e. IWE EXAMS 8 BAYS
f. TURN TORUS BACK OVER TO WPS OR
a. WPS BLAST ALL SIXTEEN BAYS
b. IWE EXAMS ALL SIXTEEN BAYS
c. TURN TORUS OVER TO W S
2. STRATEGY
a. UT BAD AREAS I.D.d DURMG AS FOUND
b. EVALUATE THIN AREAS AS NECESSARY C. ACCEPTANCE CRITERIA

TORUS INSPECTION STRATEGY Based upon a meeting on 3/18/98 with Project Engineering, Design Engineering, and Williams Power the following represents the framework of how we, as part of Strainer Replacement Project, will proceed with inspections.

1) During and after torus draining, cleaning and drying, areas of concern or c

interest will be:

- marked on the ID of the torus, and

- mapped/documented on paper.

Williams will scrape corroded areas (not paint) as directed or as needed.

2.a) With RP approval, a local sand blast vacuum box or hand scraper will be used to clean the areas of concern, or 2.b) Without RP approval, the local sand blast box will be used for cleanning after the general torus sandblast effort is complete.

Williams will mask/protect the identified areas until the general area sandblasting effort is complete.

3. Inspect the areas of concerns (from the ID or OD) and provide quantitative results to engineering for evaluation. It is preferred to have engineering on site and in the torus during the inspection effort to assist in screening out irrelevant concerns.
4. Engineering will disposition inspection results and:

- accept as is, or

- prescribe repair directions.

For large gross areas, a FAC type inspection will be performed.

If the number of locations exceed 200, the project will suspend the efforts of inspection and regroup to establish a new course of action.

5. Upon completion of sandblasting in an adequate number of bays to provide worker separation, bare metal examination will be begin. "Adequate number" will be established by affected work parties through close communication and coordination.
6. New findings will be dispositioned by engineering.
7. After the new coating is applied, a baseline (as-left) inspection will be performed .

Downcomers - Inspections will performed of repaired areas.

Vent Header - Inspections will be performed of repaired areas.

Other areas of the torus and vent header will be inspected as prudency warrants.

Outstanding Items:

1) Jim Callaghan to identify the engineer whd will provide close support of the inspection efforts. Item Closed: Jim Fitzpatrick will provide this engineering support.
2) Jim Calchera to obtain approval

__ from RP to use local vacuum sandblast box techniques.

If you have comments or wish to further refine the above, please let me know.

Dennis Girroir (X-5578)

From: Dennis Girroir (CVAX:GIRROIR-D)

To: Corbett Date: March 2 4 , 1998, (Tuesday) 3:47pm

Subject:

or us - IWE Inspections Pat

+

The 1st phase of IWE Torus inspections is in progress. Preliminary results are very encouraging in that the torus coating general condition is in quite good shape.

... ~

1) We have walked down the lower portion of the shell and identified less than a dozen locations that will need further inspection and possible disposition.

One deep pit (identified by earlier maintenenace inspections) was re-identified.

2) The bottom center of the torus needs further inspection attention as a result of general wear/travel type of coating degradation.
3) The upper 6+ feet of the torus (to the water level) will be inspected as ladders and/or staging is available. As you move up the torus wall the general condition improves.

4 ) Of particular interest are those hundreds of locations ineach bay that were repaired in the past underwater. We do not know the condition of the torus shell in these locations. We are entertaining a sampling plan with the assistance of Jim Fitzpatrick of Design Engineering. Tonight we map out each indication in two bays.

5 ) We are preparing to strip paint on the OD of the torus for items 1 & 2 above. We therefore will not need to wait on sandblasting to determine their disposition.

6) We are also pursuing a document search for item 4 to identify the criteria or basis for the underwater coating effort. Interviews will follow as personnel are available.

In summary it would appear that the torus coating issue is manageable at this time. As this assessment changes a new status is warranted. Ill keep you updated.

Dennis cc : Dugan,Schaefer,Larsen,Jefferson,Maret,Leach_D,Lindamood, ...

.--. 3: *-

-- -- - - - N V 7 z - -

TRANSDUCER c PItCH/CATCH

, MAYE/HODEL: k-fi@.)ul&-trC

+k!@ MODE: 0 PULSE/ECHO FREQUENCY: SIZE: r5BV CAL. a i o w 1 MATERIAL: ds PROOUCT FORM: hl 70&$%# THICKNESSES: ,5%J'> -753, CALIBRATION I ES r,~-obr

  • INITIAL: hq4-L CHECK: io!(c- CHECK: p h

. CHECK: A.+& F1NALz-e.

Toms IWE examination status as of 4/10/98:

The entire bottom interior of the Torus has been examined with existing coating intact to approximately 12 above the water line. The result of this examination has been:

4 The general conditions varied .from moderately degraded topcoat with intact primer coat to degraded primer coat with exposed substrate and minor corrosion. There were 9 specific areas identified that exhibited coating degradation andor substrate corrosion that exceeded the general inside surface conditions. Also,

- 379 individual previously repaired locations in bay 8 and 16 were mapped for analysis by Design Engineering (bays 8 and 16 had the highest incidence of previous repair areas).

J The 9 specific areas were mapped and 7 of them were transferred to the outside where the lead paint was removed, grids applied and UT thicknesses taken for Design Engineering review. The remahhg 2 areas were gridded on the inside, lead paint was removed and UT thicknesses were taken for Design Engineering re^+*^^ [these areas were done from inside because of structural member obstructions on the outside,.) The results of these UTS are being used in Design Engineerings evaluation process. In bays 8 and 16 a 2 wide by 19 long area was lead abated, gridded and UTd to provide engineering data. Approximately 4500 discreet thicknesses were taken during this analysis phase.

J In conjunction with the areas above, lead paint was removed at 16,ldiameter locations in each bay (total of 256 locations) for individual thickness readings to be used for actual plate thickness determination.

Subsequent to Design Engineering receiving the UT results of these areas, 12 additional plate Iocations were identified for thickness dimensioning. These additional areas have had the lead paint removed and will be UT examined in the next several days.

J UT thicknesses have been taken in bays 8 and 16 on the gridded areas noted above both prior to and after blasting to determine if blasting would remove any significant amount of base material. As of this time the data would indicate no significant material loss due to blasting. There was a -.003calculated average material loss in bay 16 which is within the tolerance of the UT instrument used to perform the thickness examination. Approximately 5000 discreet thicknesses were taken during this analysis phase.

J- The initial torus vent header visual examination has been performed and there were 5 to 7 areas identified that will require mapping and based on Design Engineering input may require UT dimensioning from the outside of the vent header. The mapping will be performed after blasting is complete.

J Blasting is currently being monitored to determine when access will be permitted for the visual examination of the blasted surface - as of 1600 today (410) it looks as if we will have access either during tonights night shift or day shift tomorrow. Williams Power is indicating that the bays that have been blasted still contain a significant amount of blast medium and coating residue that will have to be removed prior to our examination.

b "

P

__.__.____.__ ).-- _ . _ _ - _ - _ ..-- ..-.- -.-. - . ... . . . . . .- .... -,. ._. . . . .. . . . .

Torrrs IWE emminution status as of 4/I9/98:

The entire bottom interior of the Torus has been examined with existing coating intact to approximately 12 above the water line. The result of this examination has ken:

J The general conditions varied from moderately degraded topcoat with intact primer coat to degraded primer coat with exposed substrate and minor corrosion. There were 9 specific areas identified that exhibited coating degradation andor substrate corrosion that exceeded the general inside surface conditions. Also, 379 individual previously repaired locations in bay 8 and 16 were mapped for analysis by Design Engineering (bays 8 and 1G had the highest incidence of previous repair areas). . -

J The 9 specific areas were mapped and 7 of them were transferred to the outside where the lead paint was removed, grids applied and UT thicknesses taken for Design Engineering review. The remaining 2 areas were gridded on the inside, lead paint wils removed and UT thicknesses were taken for Design Engineering review (these areas were done from inside because of structural member obstructions on the outside.) The results of these UTS are being used in Design Engineerings evaluation process. In bays 8 and 16 a 2 wide by 19 long area was lead abated, gidded and UTd to provide engineering data. Approximately 4500 discreet thicknesses were taken during this analysis phase.

J In conjunction with the-areas above, lead paint was removed at 16, 1diameter locations in each bay (total of 256 locations) for individud thickness readings to be used for actual plate thickness determination.

Subsequent to Design Engineering receiving the UT results of these areas, 12 additional plate locations were identified for thickness dimensioning. These additional areas have had the lead paint removed and will be U T examined in the next several days.

J UT thicknesses have been taken in bays 8 and 16 on the N d e d areas noted above both prior to and after blasting to determine if blasting would remove any significant amount of base material. As of this time the data would indicate no significant material loss due to blasting. There wits a -.003calculated average material loss in bay 16 which is within the tolerance of the UT instrument used to perform the thickness examination. Approximately 5000 discreet thicknesseswere taken during this analysis phase.

2 The initiaI torus vent header visual examination has been performed and there were 5 to 7 mas identified that will require mapping and based on Design Engineering input may require UT dimensioning from the outside of the vent header. The mapping will be performed after blasting is complete.

J Areas containing laps in the base material have been identified in bayqf I, 12,15 and 16. These areas have been mapped and UTd to determine if any Iaminar type defects lie in the throughwall material in these locations. All weas have been UTd from the OD and the ID. Thicknesses in these areas me above the J

\.

nominal values and no laminars have been found to date.

Blasting is currently being monitored to determine when access will be permitted for the visual examination of the blasted surface - as of 1600 today (4/19) it looks as if we will have access either during night shift tomorrow (4/20) or day shift Tuesday (4/21).

The interior of the torus vent header was examined on 4/8/98 and the followtng items were identifled:

Previously Identifiedh a s :

The a r e s previously identified as 96-RH-001 througb 96-RH-012 (seeattached copy d tenance Dept.

%ing Header, Vent Pipe and Downcomer Interior Inspectim Record taken from 9/25/96)were examined and found to be larger than identified in 1996. Also, the conosion identified during the 1996 examination appears to be more advanced thaa the estimated 1996maximumof .005.No estimate of additionalmaterial loss was able to be made during his vent header entry.

The followingareas were not noted in the 1996examination report:

Bowl Areas:

Bowl A Vertically aligned areas of missing and degraded coating with corroded substrate.

Bowl B: Vertically aligned areas of missing and dekded coating with curroded substrate.

Bowl C Small localized spots (1 to 2 in diameter) of missing and degraded coating with conoded substrate.

Bowl D: SmaU localized spots (1 to 2 in diameter) of missing and &graded coating with corroded substrate.

Bowl E Vertically aligned areas of missing and &graded coating with corroded substrate.

Bowl F: Vertically alignedarm of missing and degraded coating with corroded substrate.

Bowl G Areas of missing and degraded coating with corroded substratein areas where water had obviously pooled. Corrosion is more severe at the waterline in areas where there are indicationsof standing water.

Bowl H Areas of missing and degraded coating with corroded substrate in areas where water had obviously pooled. Corrosion is more severe at the waterline in areas where there are indicationsof standing water.

General interior surfclce:

The bottom portion of the vent header (includingbowls) shows numerous small (1to 2 in diameter) areas of missing and &graded mting with corroded substrate. The greatest n u m b of theseareas are located m bays 10,11, 12,14,15 and 16. These locations are more numerous m bays 14,15 and 16, hdivever, the cOrrOSiOa in these areas does not appear to have significantlydegraded the subsrrate. Them are also several Iarger localized areas of missing and degraded coating with corroded substrate (averaging approximately 3 X 10 in she) on the bottom of several bays near the bottom seam welds. In these areas there is evidence of light pitting and erosion. The wont of these areas are in bays 13,14,15 and 16 with the inqations in bay 15being the m a t evident.

The sides and uppea portion of the entire vent header inmior have areas of topcoat degradation and loss with no apparent substrate corrosion.

Torus interior VT indication locations:

Locations as noted below The Following areas were noted as having corrosion and/or coating degradation exceeding the g e n d conditions in the associated bay:

c l3av 1 1 - 3" x f Y strip of tnrxlcriitte tnrxlcriite corrosion, coating degradation and exposed suhstrrrtclocated 6': fmn bottom seem weld towards OD of torus itnd 10" from h ~ lya1 ring girder.

2 - On thc interior of downcomer #5 thcre is 5" x 14" area of moderate corrosion, ccming dcgndation 'and exposed substrate located 2" from bottom edge. This ara?lies wholIy within the scction of the downcomcr that is king removcd.

Bav 2 1 - There is a sin& pit (physimfly idcnlificd on the torus shcll as having 'an extuninntion date of 9/96} located 1 I' 6" towwd UIC torus ID from thc bottom SCim wcld 'and 18" from Ihc vertiod center pliite wcld.

2 - Thcre is a 4" x 5" area of moderate corrosion, coirting degradation and exposed substrate located 20' 10" toward the torus OD from the bottom seam weld and 9" from bay 2/3 ring girder, Bav 3 1- Interior of downcomers 1,2,3,6 and 7 have a moderate powdery cortosioa,coating degradation and exposed substrate00 the interior surface intrados at the conjunction of the upper and lower pieces.

m1 - There is a 60" x 12" strip of moderate corrosion, coating degradation and exposed substrate extending &om 56" &om the bay 5/6 ring girder to 116" from bay 5/6 ring girder. This area foftows the bottom seam weld (6" on either). The seaamwcld is on thc centcrline of Ihc long axis of the strip.

2 - Thcre is a 9" x 12' area of minimal pitting, moderate corrosion, coating degradation and exposed substrate 43" from Bay 5/6 ring girctcr and 56" toward reactor vessel from the bottom center seam weld.

3 There is a 24" X 24" area of moderate corrosion, coating degradation and exposcd substrate 145' from the bottom seam weId 26" Born Bay 4/5 ring &der toward the torus OD.

4 There is zl6" area of blistered mting on the interior, 12" fiom the bottom edgc of downcomer #5,2' CCW from the longseam.

5 - Thcre is a 3" x s'area of area of moderate corrosion, mting degrahtion am&xposed substrate on the interior of downcomer WI, 3" from the bottom edgc of the downcomer, starting at the longseam and extending T'CCW.

Bav I1 1 There is a 6" x 6' area of moderate corrosiot+,coatingdegradation and exposed substrate below the miter weld at the intradosof the interior of downcomer #1.

2 - "I3er.e is a 6" x 6' area of moderate corrosion, mating degradation and exposed substrate below the miter weld at the intradosof the mteaior of downcomer e.

Bav 12 1 There is a 6" x 6" strip of moderate corrosion, coating degradation and exposed substrate 21" from the bay 11/12 ring girder arid 88" from the bottom seam weld away from the reactor vesse1.

2 - Thcre is a 24" x 12" area of moclcratc corrosion, coating degradation ,and cxposed substrate extending from 90" From thc bottom .seam weld toward Uie torus OD, 6' from the tx?y 11/12ring girder.

Bay I3 There is a single pit located 5" down from tlie miter weld and 6" ccw on Urn interior of downcomer #8.

Bcrv 15 I There is n 6" x 6" nrczz of modcrate corrosion, co(?ting degradiition nnd exposed substrate, 19' 10" toward the torus OD from the bttom seam weld, at h e bay 14/15 ring girder.

Bav 16 There is light blistering on the interior of downcmer #3.

The following downcomers have dents with moderate corrosion, coating degradation and exposed substrate on the

- bottom edge within the 6" area that is to be removed.

Bay 4 - Downcomer #1* ...

Bay 5 - Downcomer #4

.: ,~

Bay 6 - Downcomer #3 Bay I1 -Downcomcr #4 Bay 15 -Downcomer #d b

From: Mike Dugan (CVAX:DUGAN)

To: CALCHEaA, GIRROIR-D, HUMBERT, SCHAEFER, TAINTOR, WUOTI Date: May 8, 1998, (Friday) 9:45am subject : Outstanding Torus NDE All ,

This is to inform anyone concerned of the outstanding NDE required to be performed by Project Engineering in accordance with the IWE portion/and in support of the T o r u s Project.

The following is an outline of the outstanding NDE as of 5/8/98 a.m.:

1. Bay 7 UT after blasting in 16 locations identified by Design Engineering (the other 15 bays were completed 4 / 2 2 ) . This is being performed today ( 5 / 8 ) .
2. Bays 4 and 15 require thickness readings as directed by Design Engineering in the area of the baffle plate support reinforcing plates. This is being performed today (5/8).

3 . VT-1 examination of the torus access hatch bolting: The NW hatch bolting is complete and acceptable. The SE hatch is missing 4 nuts that, per the drawing, should be tack welded to the underside of the hatch flange and is also missing 3 bolts that have not been located. Williams Power has been notified (Don Wuoti) and we are awaiting word as to the location of the missing nuts and bolts. Also, a VT-1 of the bolting is required after the hatches have been reinstalled.

4. The bay 7 access plate cutout requires further VT-1 examination after the protective edge covering is removed.
5. There is an area on the interior of bay 7 that requires VT-1 examination after coating removal.
6. All coated areas of the torus require a final VT-1 baseline examination when all work and coating is completed.

If anyone is aware of any required NDE not identified on this list please bring it to the attention of myself at ext. 5618 or Dennis Girroir at ext. 5578.

Thank you, Mike Dugan

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