IR 05000338/1981001
| ML19350C272 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 02/23/1981 |
| From: | Economos N, Herdt A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML19350C271 | List: |
| References | |
| 50-338-81-01, 50-338-81-1, NUDOCS 8103310789 | |
| Download: ML19350C272 (6) | |
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UNITED STATES f
7, NUCLEAR REGULATORY COMMISSION
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<E REGION 11 p'['
101 MARIETTA ST, N.W., SUITE 3100 g
ATLANTA, GEORGIA 30303
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Report No. 50-338/81-01 Licensee: Virginia Electric and Power Company Post Office Box 26666 Richmond, VA 23261 Facility Name: North Anna Power Station Unit 1 Docket No. 50-338 License No. NPF-4 Inspection at th na ~ e n ar Mineral, Virginia Inspector:
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N. Eco onics '
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Approved by:
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A. R. Herdt, Section Chief, RC&ES Branch Date' Signed SUMMARY Inspection on January 19-23, 1981 Areas Inspected
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This routine unannounced inspection involved 34 inspector-hours onsite in the areas of inservice inspection activities; steam turbine rotor low pressure disc cracking. The inspector attended VEPCO's presentation of the turbine rotor discs ultrasonic examination results to NRR in Bethesda, MD.
Results Of the two areas inspected no violations er deviations were identified.
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.Y DETAILS 1.
Persons Contacted Licensee Employees
- W. R. Cartwright, Station Manager
- E. W. Harrell,- Assistant Station Manager H. L. Travis, Mechanical Foreman - NDT Other licensee employees contacted included craftsmen, technicians and office personnel.
Other Organizations Nuclear Energy Services, Inc. (CONAM)
J. J. Funanick, Level-IIA Eddy Current Westinghouse - Nuclear Technology Division (W)
W. Hazlet, Level II Ultrasonic Inspection (UT)
R. Haines, Level II, UT NRC Resident Inspector.
E.. Webster
- Attended exit interview 2.
Exit Interview I
'The inspection scope and findings were summarized on January 22, 1981 with those persons. indicated in Paragraph 1 above. The areas inspected included inservice inspectiot, activities and results of steam turbine rotor discs UT-inspection.
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Licensee Action on Previous Inspection Findings Not inspsected.
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Unresolved Items l-Unresolved-items are matters about which more information is required to l
determine whether they are acceptable or may -involve noncompliance or deviations.
New unresolved items identified during this inspection are
discussed in Paragraphs 6 and 7.
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Independent Inspection Effort Main Turbine UT Surveillance At the time of this inspection, W had completed the examination of the main turb ne low pressure disc keyways.
This examination was performed in respunse to recent industry experience where stress assisted corrosion cracking has occurred in the keyways of turbines rotors with shrunk on disc design.
Since turbine disc and keyway design precludes the use of standard UT techniques W has developed a technique which utilizes computerized tangential and radial aim scans to detect, verify and measure the depth of crack indications.
Records of the examination were reviewed for completeness, accuracy and clarity of content. %sults of the examination indicate that the discs on low pressure (LP) rotor #1 were free of any reportable indications.
the discs on LP #2 were free of indications with the following exceptions:
The No. I disc, governor end, outlet side, displayed a tangential aim
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indication in the disc keyway at balance hole No. 28. This indication was confirmed with the use of the radial aim technique, the depth is estimated to be.360" deep.
The No. 1 disc, generator end, outlet side, displayed a tangential aim
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indication in the disc keyway at the balance hole No.1. This indi-cation was confirmed with the use of the radial aim technique,the depth is estimated to be.200" deep.
The W recommendation was that the rotors were suitable for operation with the proviso that disc #1, LP #2 must be reinspected in six months.
Discuss lons with site management disclosed that efforts were underway to purchase the Three Mile Island Unit 2 turbine rotor assembly if it is ultrasonically sound. Otherwise, the present discs will be replaced with a baffle which will permit the plant to resume operation but at a reduced power rating.
VEPCO, assisted by W, presented these findings to NRC headquarters staff on January 23, 1981. According to W the analysis showed that in both cases the
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depth of these cracks were less than 50% of the critical crack size predicted by fracture mechanics. The staff had no questions on the findings and the proposed fix. The inspector attended the presentation.
Within the areas inspected no violations or deviations were identified.
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Inservice Inspection - Review of Procedures This work effort was related to the second refueling outage which began on
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or aoout January 6,1981 and was still in progress at the time of this inspection. Nondestructive examinations /ISI. activities were conducted by W
under contract with VEPCO.
The - controlling document is W Inspection Program Plan for_ Unit 1.
This manual and related ISI procedures had been approved by W Level III Examiner and VEPCO's cognizant NDT representative on
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December 19 and 31, respectively.Section XI of the ASME Code 1974 Edition through the 1975 summer addenda controls NDE requirements. Components / Parts scheduled for ISI during this outage include the reactor vessel closure head weld, flange to vessel welds, ligaments, nozzles, pressurizer welds, sup-ports and bolting, various Class 2 parts and components including supports and valve bolting.
Areas subject to examination during this outage were selected at random from the W Plan and reviewed to ascertain whether procedures, examination cate-gory, method and extent of examination as required by the Code were deline-ated.
The areas selected were as follows:
IWB-2500 Examination Areas Category Item Method Closure Head Weld B-B 1.3 VOL.
Outlet Nozzles B-D 1.4 VOL.
Vessel to Flange B-C 1.3 VOL.
Flange Ligaments B-G-1 1.9 VOL.
Przr. Nozzle to Vessel B-D 2.2 VOL.
IWC-2520 Areas Category Item Method Heat Exchangers Shell Welds C-1 1.1 VOL.
Support Welds C-C 1.3-SURF.
Studs C-D 1.4 VIS.
Nonregenerative Heat Exchanger Bolts C-D 1.4 VIS.
Regenerative Heat Exchanger Head to Shell Weld.
C-A 1.1 VOL.
Procedures used to perform the required.NDE examinations were reviewed for technical adequacy and for compliance with Code and Regulatory requirements.
In that these procedures have' been reviewed on previous inspection, a
. greater emphasis was placed on their revisions / amendments.
Liquid Penetrant Examination ISI-11-Rev. 9 Amend. 3
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ISI-7 Rev. O Amend.1
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Magnetic Particle Inspection Ultrasonic Examination of Studs Bolts and Nuts ISI-15 - Rev. 6 Amend. 2
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Visual Examination
'ISI-8 Rev. 7 Amend.1
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ISI-41 Rev. 4 Amend. 2
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Manual UT of Reactor Coolant Pump Flywheels Manual UT of Full Penetration Circumf. and ISI-205 Rev. 2 Amend. 3
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Long. Butt Welds Operation Procedure for the Inservice of ISI-152 Rev. 6 Amend. 1
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Reactor Vessel Using W Remote Inspection Tool ISI-01
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Reactor Vessel Inspection Program-Preoperation and Documentation 42-EC-041 Rev. 0
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Multifrequency Eddy Current Procedure Within these areas the inspector noted that the eddy current (EC) procedure 42-EC-041 Rev. O, had several areas which lacked specificity, e.g., (a) the qualification level (ASNT-TC-1A) for the individual in charge of the exami-nation was not specified except that he was required to be qualified to CONAM's requirements, (b) conditions under which calibration of the system would be confirmed were not specified; (c) there was no reference to code other that the procedure was in compliance with R.G.1.83.
The inspector discussed the matter with CONAM's representative and VEPC0 who stated that calibration was confirmed / checked whenever system changes occurred and agreed to revise the procedure to cover the areas discussed above. A draft revision was generated prior to the end of this inspection. The inspector stated this matter would be identified as unresolved item #50-338/81-01-01,
" Revision of EC Procedure 42-EC-041".
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Inservice Inspection - Observation of Work and Work Activities The inspector reviewed completed and projected _ percentage of examinations for Class l'and 2 components for compliance with tables IWB-2500, IWC-2500 and paragraph 'IWB-2400 of _ ASME Section XI. Personnel qualifications along with corresponding eye examinations were. reviewed for consistency with
. applicable requirements.
Work observation was concentrated on reactor vessel inspection, performed with the W remote control inspection tool. The inspector through observa-tion and interviews determined that:
(1) approved NDE procedures were i
available; (2) assigned personnel were qualified and knowledgeable of the examination method and equipment; and (3) examination results were being accurately documented. Reactor. vessel welds under examination during this time of observation included:
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Examination Weld Location Method Comments i
Vessel to Flange Stud Holes I thru 12 UT,0,45 L NRI j
and 45 thru 51-Vessel Outlet Nozzle Loop 1, 24.9 0* and 45 L NRI For these welds the inspector witnessed system calibration and a portion of
.the scanning program. Also, the inspector reviewed previous calibration
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records, computer print-outs of weld scans and transducer-certifications.
Calibration stickers on equipment were checked and found to be in order.
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Problems with the electronic circuitry used to control the movement of the tools Z axis caused numerous delays in the inspection of these welds. The inspection effort was finally abandoned on January 23, when the horizontal arm drive of the tool broke down during inspection of the second outlet nozzle. This problem occurred after the inspector's departure from the site.
Site managment notified RII and at the same time discussed the apparent Code deviation arising from the unforeseen inability to complete the nozzle examinations. The VEPCO representative offered to provide, and RII agreed, a letter stating the problem and the steps taken to resolve it.
Within these areas the inspector noted that certain provisions of procedure ISI-152, " Ultrasonic Examination of Reactor Vessels Utilizing Remotely Operated Equipment" were being bypassed by )[ ISI personnel. These included paragraph 7.7 which requires that water velocity and amplitude be checked each time the tool passes through a certain location on the vessel (heme position), and paragraph 8.2 which requires that at predetermined points /
scan patterns be displayed on the terminal scope (CRT) and printed out as a permanent record.
Discussion with the )! representative disclosed that with the combination of field expertise, equipment and computer programming these checks are unnec-essary and time consuming. Further the W representative stated that these steps will be deleted from this procedure which is now undergoing revision.
The inspector was in general agreement with the )! position but stated that this matter will be identified as an unresolved item pending revision and review uof the revised procedure, Unresolved Item No. 338/81-01-02, "Revi-sions to Field Calibration and examinations under )[ procedure ISI-152 Rev. 6 Amend. 1".
Within the areas inspected, no violations or deviations were identified.
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Eddy Current (EC) Examination of Steam Generator (SG) Tubes ISI activities during this refueling outage (2nd) included the eddy current (EC) examination of tubes in "A", "B",
and "C" SGs.
Data acquisition and analysis was being performed -by CONAM personnel.
The approved procedure 42-EC-041 Rev. 0 which referenced R.F. 1.83 R/1 was the governing document.
In SGS "C" and "B" a total of 490 tubes were examined respectively.
'The tubes were being examined using a multifrequency technique, except that 400KHz was used to analyze tube integrity.
Discussions with the licensee
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disclosed that there were no tubes that required plugging other than those found to have missing plugs.
The-inspector reviewed quality records of EC calibration standards onsite, equipment certifications and personnel qualifications.
Techr.icians per-forming the examination appeared to be thoroughly familiar with procedural requirements and adequately qualified to perform their assigned tasks. Tube
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examination was still in progress at the close of this inspection.
Within the areas inspected no violations or deviations were identified.