ML20148C443
| ML20148C443 | |
| Person / Time | |
|---|---|
| Issue date: | 09/09/1978 |
| From: | Brown R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20148C371 | List: |
| References | |
| REF-QA-99900042 NUDOCS 7811020049 | |
| Download: ML20148C443 (9) | |
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- 9 VENDOR INSPECTION REPORT l
U. S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION IV Report No. 99900042/78-01 Program No. 44040 Company: Babcock & Wilcox Company Mount Vernon, Indiana Inspection Conducted: August 15-16, 1978 Inspector: v- 9/ F Ro'ss L. Brown, ComponentsSection II ' Da'te Vendor Inspection Branch Approved by: 277 Mr <- e v>. te u'21"~ 7/77 D. M. Hunnicutt, Chief, ComponentsSection II 'Date Vendor Inspection Branch Suninary Special inspection on August 15-16, 1978 (99900042/78-01)
Areas Inspected: Collection of information related to the reported weld material discrepancy including nature, extent of problem, weld material identification, weld materials analysis and tests results, and preventive actions. The inspection involved sixteen (16) inspector hours on site.
Results: The information indicates that, as a result of chemical analyses performed on archive weldments for evaluation of reactor vessel material properties, it was discovered that weld filler material atypical of the submerged arc welding electrode used by B&W in the construction of nuclear pressure vessels was some how mixed with the Mn-Mo-Ni filler material.
Those vessels with the atypical weld material possess a higher than normal unirradiated reference temperature RTNDT, and the future operation of the plant may be pverned by more restrictive pressure / temperature limits, which will require changes to the Technical Specification.
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The documents reviewed also identified the twelve-(12) reactor vessels involved and the particular weld seam (s) of each vessel that contains the atypical weld metal.
B&W stated that the customers for these twelve (12) reactor vessels have been notified of the problem, action taken by B&W to ascertain the extent of the problem, and the B&W position relative to the problem.
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DETAILS SECTION A. Persons Contacted
- G. N. Emmanuel, QA Manager R. A. Fearing, Metallurgist C. A. Maher, Supervisor, Material Control R. B. McClellan, Supervisor, Material Control Warehouse
- R. L. Rogers, Manager, QA Engineering K. B. Stuckey, Project Manager, Special Vessel Contracts
- Attended Exit Interview B. Special Inspection
- 1. Objective The objective of this inspection was to gather information relative to the use of atypical welding electrode in reactor vessels during shop fabrication.
- 2. Method of Accomplishment The preceding objective was accomplished by:
- a. Review of laboratory test results of the atypical weld material contained in one surveillance material block.
- b. Review of chemical analyses of thirty-two (32) weld samples containing the suspect heat (72105) of welding electrodes,
- c. Review of compilation of all the wire-flux qualification tests that were made for Manganese-Molybdenum-Nickel (Mn-Mo-Ni) electrode used in the B&W plant at Mount Vernon during the period 1967 through 1971.
- d. Review of the list of twelve (12) reactor vessels and surveillance blocks for one vessel, that was welded using the suspect heat of electrode.
- e. Review of electrode manufacturers certification of analysis.
- f. Review of the draft copy of procedures MV-10ll-03 and 12-2-MR-1 for the qualification, release and testing of all welding materials to be used in the Mount Vernon plant.
- g. Review of a draft letter to B&W customers that summarizes the atypical weld material problem and states the B&W position relative to the problem,
- h. Interview with cognizant personnel.
- 3. Findings During the review of the above documents, records, and interviews, the following ir. formation was obtained.
- a. Nature of problem The specified chemical analysis of the as deposited Mn-Mo-Ni weld material was C-0.05, Mn-1.30-1.60, Si 0.30-0.60, P-0.025, S-0.025, Ni-0.45-0.80, Mo-0.30-0.60, Cu-0.35.
The chemical analyris of the deposited weld metal (Heat No. 72105) in the Surveillance Block No. 2 for the Crystal River III vessel revealed high Si, and law Ni content. The determined values were outside the specified range: specif-ically the Ni content was 0.1% (typically 0.6%) and Si content was 1.0% (typically 0.5%).
The mechanical properties of the atypical weld were satisfac-tory from a strength standpoint, however, the RTNDT temperature is approximately 1200 which is 800F higher than that normally specified.
The vessels that contain the atypical weld wire were construc-ted in accordance with the ASME B&PV Code,Section III,1965 Edition, Addenda through Summer 1967, which did not have the RTNDT requirements. The basic requirement was that the material exhibit a 30 f t-lb charpy at a temperature which was at least 600F lower that the hydro temperature and the lowest service metal temperature.
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contract vessel No., weld seam No., weld procedure, heat and lot number of electrode and flux, welder, supervisor, etc.)
for all nuclear fabrication in their plant for the 1967-1971 time period, to identify the vessels and weld seams that con-tain the atypical weld wire, Heat No. 72105. The following information resulted:
Vessel Weld Seam (s)_
(1) Oconee II SurveillanceBlocks(only).
(2)ThreeMileIslandI Nozzle Belt to Upper Shell and Outer 50% of Lower Shell to Dutchman.
(3) Three Mile Island II Low areas Built-up (1/4 max.) on 10 and OD of upper Shell and Dutchman to Lower Head.
(4) Crystal River III Upper Shell to Lower Shell, Core Flood & Outlet Nozzle to Nozzle Belt and Surveillance Block.
(5) Arkansas Nuclear One Inlet & Outlet Nozzles to Nozzle Belt and Closure Head Dome to Flange.
(6)OconeeIII Inlet & Outlet Nozzles to Nozzle Belt, Outer 25% of Upper Shell to Lower Shell, Dutchman to Lower Head and Surveillance Block.
(7) Rancho Seco I Vessel Flange to Nozzle _ Belt and inner 75% of one Long Seam in Lower Shell.
(8) Midland 2 Outer 50% of the circle seam in the Nozzle Belt, Upper Shell to Lower Shell and Surveillance Block.
(9)ZionII Two (2) Long Seam in Lower Shell and Surveillance Blocks.
(10) Zion I Upper Shell to Lower Shell and Surveillance Blocks.
(11) Turkey Point 3 1/3 of Nozzle Belt to Shell.
(12) Quad Cities 11 Closure Head Dome to Flange.
(13) Brown's Ferry I MK 59 Shell to MK 60 Shell and MK S8 Shell to Mk.'59 shell.
B&W has informed their NSSS customers that B&W has performed a technical evaluation on the B&W reactor vessels, assuming the atypical material is 1
in each of the identified locations in the reactor vessels. The fracture mechanics evaluation demonstrates that the structural integrity of the reactor vessel has not been compromised by the possible presence of the atypical material. However, those vessels with the atypical weld material possess a higher than normal unirradiated reference temperature RTNOT' and the future operation of the plant may be governed by more restrictive pressure temperature limits, which will require changes to the Technical Specification. B&W stated that they have supplied the test results and all other pertinent data to their customers for reactor vessels only.
- c. Identification and Analysis of Other Mn-Mo-Ni Welding Materials During the above review (paragraph B.3.b.) B&W determined that since 1967, thirty-four (34) heats (including the atypical Heat No. 72105) of Mn-Mo-Ni welding wire have been used at the Mount Vernon plant representing approximately 1-1/2 million pounds. One hundred and eighty (180) weld pads (wire-flux qualifications) represenr i these heats (seven (7) for Heat No. 72105) were analyzed u..; all were acceptable, however, a record of an analysis of the atypical wire Heat No. 72105 performed in January 1968 for Material Verification showed the high Silicon low Nickel content; specifically Si-0.74% and Ni-0/07%. B&W could not determine
, whether or not this discrepancy had been reported to management and dispositioned.
B&W also determined that no check analysis of the bare wire was performed at receiving to verify conformance with specified require-ments. This was not a code or contract requirement, h Never, the supplier's Certification of Analysis and the wire-flux qualification tests that were required in the 1967-1971 period, and are still required, would indicate that large portion of the 74,403 pounds of welding wire certified as Heat No. 72105 was acceptable, but the amount of the atypical weld wire could not be ascertained, and consequently the entire heat is considered to be suspect.
- d. Preventive Actions B&W QA management stated that the following procedures will be released on or about September 30, 1978.
(1) MV-10ll-03, " Qualification and Release of All Welding Materials."
This document establishes procedural controls to assure that all welding materials are properly qualif W and inspected prior to release for fabrication.
Welding materials are tested by the Materials Laboratory in accordance with the requirements of 12-2.MR-1 (2) 12-2-MR-1, " Procedure for Sampling and Testing of Solid and Fabricated Coiled and Cut Length Bare Welding Wire."
This procedure shall govern sampling and testing of solid and fabricated coiled and cut length bare welding filler material prior to use in production welding.
Spectrometric or wet analysis shall be utilized to verify that welding filler material is as represented. Testing shall be performed in accordance with this specification before the heat / lot of welding wire is released by Materials Control for use by the production . hops. c Each coil or container of each heat or lot of weld filler material shall be serialized with nonrepetitive, consecutive numbers.
Samples shall be taken in accordance with Table 1. Quantity of sample shall be in accordance with Table 2.
When one sample is required, it shall be taken from the end (top) of a 300 pounds or less coil or spool. When two (2) samples are required, they shall be taken from the beginning and end (top and bottom) of the 500 or 700 pound spool or drum.
It appears that these requirements, in addition to the Code requirements of material test reports and wire-flux qualification tests, should preclude a repetition of this situation.
- e. Historical Review of the Atypical Weld Wire Manufacturers Facility The inspector reviewed a report to the Manager, Quality Assurance from Manager, Weld Lab / School relative to an inter-view with management personnel of the supplier of weld wire Heat No. 72105. The report states the following:
(1) The company's original plant was being closed and a new operation started at the present location during the period 1968 through 1971.
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(2) All the personnel interviewed were key personnel at
.the old-plant. There are no lunger any records available !
from the original plant, consequently the information '
obtained was mostly from their recollection only.
(3) The' weld wire control number (Heat Number) 72105 was manufactured at the original plant and identified as AS-50(Mn-Mo-Ni).
(4) That during 1967 the manufacturer developed an analysis-of gas metal arc welding wire which was very much in ,
demand. This product was labeled AS18-(E70S-18).
(5) That rod bundles were supplied by a steel mill to the weld. wire manufacturers wire drawing- facilities.
(6) That only one steel company supplied electric furnace rod bundles to the wire manufacturer for both AS-50 (Mn-Mo-Ni) and AS-18 (E70S-18).
The nominal Ni of AS-18 (E70S-1B) was 0.12% Ni. These rod bundles were identified by metal tags attached to the rod bundles. Different shaped tags were used for different product grades. The rod bundles were shipped in gondola cars. Different products were shipped in the -
same gondola car. When the rod bundles were received, no chemistry checks were employed to assure heat or grade identity.
A typical rod bundle weighed between 300 and 350 pounds.
Three rod bundles were spliced together before processing.
The three rod spliced bundles were processed through all operations and coiled directly into 600 pound pay-off packs (drums). Three other spliced rod bundles were added on during the continuous drawing / packaging operation.
'eight records were kept only for purposes of measuring roductivity. -
- f. Summaty '
(1) Based on the available information, it appears that opportunity existed at the welding material supplier's plant for inadvertent inter-mixing of welding materials of the specified and atypical analyses.
(2) It does not appear likely that positive verification of such mix-up can be made at this-time on the basis of the available records, nor can the precise circumstances and the extent of such mix-up be determined.
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I (3) While the amount of the atypical weld material actually used in the fabrication of reactor vessels cannot be accurately defined, based on the available material sampling and qualification data, this amount appears to be small. Consequently, the assumption that all fabrica-tion welds made using the suspect heat of material have atypical chemistries is conservative.
(4) Based on the applicable welding material control and traceability requirements, the possibility of other similar occurrences cannot be completely ruled out although the likelihood of such occurrences is considered small. Additional record reviews and statistical analysis of available information may provide a better definition of the amount of atypical weld material which may have been used in vessel fabrication. This work is currently being pursued by B&W and will be reviewed during a sub-sequent inspection.
C. Exit Interview The inspector conducted a meeting with management representatives denoted in paragraph A at the conclusion of the inspection. The following items were discussed.
- 1. The inspector identified the documents that were reviewed during the inspection.
- 2. The inspector stated that it was apparent that B&W did not provide for an overcheck analysis of the bare wire during the 1967-1971 period, however, this was not a Code requirement at that time.
- 3. The inspector recommended that B&W instruct their source inspectors of weld material manufacturers and/or suppliers to pay particular attention to the method of maintaining traceability through the various steps of manufacture.
- 4. The vendor was informed that a copy of this report will be placed in the Public Document Room; however, B&W will receive a copy of the report for their proprietary information review, but if the report does not include any sensitive information B&W will not be required to respond.
The B&W QA Manager stated that, from the analysis of the Crystal River III surveillance material, it is quite likely that the wire used was SFA-5.18-E705-18. This is probable since the supplier of the wire is a large supplier of E70S-18, and normally processes both Mn-Mo-Ni and E70S-1B at the same time so there is a potential for mixing the two grades.
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