IR 05000336/1986024

Insp Rept 50-336/86-24 on 861103-07.No Violations Noted. Major Areas Inspected:Inservice Insp Program & Tech Spec Surveillance Techniques.Unresolved Item Opened Re Tech Spec Update to Reflect Previously Accepted License Requirements

ML20207J588
Person / Time
Site:	Millstone
Issue date:	12/16/1986
From:	Lodewyk A, Strosnider J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20207J564	List: IR 05000336/1986024 ML20207J560
References
50-336-86-24, TAC-65852, TAC-66116, NUDOCS 8701080527
Download: ML20207J588 (7)

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U.S. NUCLEAR REGULATORY COMMISSION

REGION I

Report N /86-24 Docket N License No. DPR-65 Licensee: Northeast Nuclear Energy Company P.O. Box 270 Hartford, Connecticut 06141-0270 Facility Name: Millstone Unit 2 Inspection At: Waterford, Connecticut Inspection Dates: November 3-7, 1986 Inspector: nhlw / /2llSlff 4( K t'odewyV," Reactor Engineer ' ~ cfa't e

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Approved by: f /2 4[#4

[ f. R. Strosnider, Chief, Materials and date l/ Processes Section, EB, DRS, RI Inspection Summary: A routine, unannounced inspection was conducted during November 3-7, 1986 (Report No. 50-336/86-2a) of the licensee's Inservice Inspection and Technical Specification Surveillance activities. Those areas inspected include the licensee's responses to previously identified NRC items and Eddy Current Testing of the facility steam generator tubes. Inspection details included review of ISI procedures, examination equipment, quality control measures and data collection record Results: During this inspection, one previously identified NRC item was closed and no violations were identified. However, one unresolved item was opened regarding the update of Millstone 2 Technical Specifications to accurately reflect a previously accepted license requiremen '

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DETAILS 1.0 Persons Contacted Throughout this inspection, various site and corporate office representa-tives were interviewed for information and auditing purposes. Those persons contacted include the following:

Northeast Nuclear Energy Company

• T. Blanchard, ISI Coordinator (Engineering)

E. Perkins, Licensing Department representative S. Scace, Unit 2 Station Superintendent

• J. Stetz, Unit 1 Station Superintendent US Nuclear Regulatory Commission G. Grant, Resident Inspector

• T. Rebelowski, Senior Resident Inspector

• denotes those persons present at the exit meeting conducted at the close of this inspection on November 7, 198 .0 Licensee Action on Previous Inspection Findings (Closed) Deviation (50-336/85-08-01) regarding the licensee's commitment to use a curved calibration block for ultrasonic examination of Reactor Coolant System piping. On April 25, 1985 the licensee was issued a Notice of Deviation regarding the use of a flat calibration block (no. UT-6) not of the same physical design and construction as the piping to be examine The calibration block requirements committed to by the licensee are defined in ASME B&PV Code,Section XI. Follow-up inspection report 50-336/85-13 determined that those piping examinations using calibration block UT-6 were completed with adequate sensitivity and were technically acceptable. To resolve the discrepency between inspection activities and license commitments, the licensee has submitted a formal relief request to the NRC for approval of the deviation from ASME Code requirements. The request provides for use of calibration block UT-15 for large diameter (30 inch and 42 inch) Reactor Coolant System welds. This alternative examination calibration includes witnessing by the site ANII for meeting ASME Code examination requirements and will be reviewed under a separate NRC proces This item is close .0 Eddy Current Testing of Steam Generator Tubes The subject of this inspection included those activities involving the eddy current testing (ET) of the Millstone, Unit 2, steam generator The reference documents utilized during this inspection are denoted in attachment I to this repor The particular aspects and results of this inspection are discussed in detail belo .

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3.1 Technical Specification (TS) Surveillance Requirements for Millstone Point Unit 2 Steam Generators At Millstone, Unit 2, the Nuclear Steam Supply System utilizes two steam generators to transfer the heat generated within the reactor (primary system) into the secondary system and produce high quality steam for the turbine system and power generation. Technical Specification (TS) section 4.4.5 stipulates surveillance and Inservice Inspection (ISI) requirements to assure the continued integrity and operability of the steam generator tubes which are a portion of the reactor coolant pressure boundary. Those TS surveillance requirements reviewed during this inspection include:

a) steam generator tube sample selection criteria used to establish the outage Eddy Current Testing Programs b) classification and plugging criteria for degraded tube During this refueling outage, Inservice eddy current (ET) inspection was performed on steam generator (SG) Nos.1 and 2 in accordance with the following ET Programs:

Full Length Program 1200 tubes per SG, inspected from tube sheet to tube sheet First Support Program 100% of the tubes in each SG, inspected up to the first eggcrate support In addition, the licensee has planned inspection of the SG tubes with an 8 coil profilometer probe for measuring tube deformation. Advanced computer techniques may be used to analyze tube cross sections for profile, strain, and other characteristics. Primarily, profilometry will be used to assist in monitoring the progression of tube dentin At the conclusion of this inspection, most tube flaws identified were within the SG sludge pile area and were located within the first 14 inches above the top of the tube sheet (within the sleevable range). The types of indications identified consisted of small volume flaws and distorted tube sheet signals. At the close of this inspection, three additional degraded tube indications in the Full Length Program were being reviewed

, for cause of degradation and similar configuration tubes were being investigate The results of the ET Programs will be reported separately by the licensee to the NRC upon activity completion and will be included within the site 1986 Annual Repor .

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During review of Technical Specification plugging criteria, the inspector noted that the current TS revision (Amendment No. 89) does not clearly state the plugging limit for sleeved SG tube TS Amendment No. 89 was issued March 1, 1984, and included a note which states "The plugging limit for sleeves will be determined prior to (the) next refueling outage." The 'next' refueling outage for Millstone, Unit 2, occurred from March through May of 1985. Engineering representatives directly involved with SG ET inspections proposed that absent a specified limit, the con-servative approach would be to plug any tube sleeves with detectable wall penetration Thus, during the 1985 outage three tubes were plugged which contained greater than 20% through wall sleeve degradation. Discussions with licensing department representatives and a review of associated correspondence revealed that a sleeve plugging limit of 40% through wall had been established prior to the 1985 outage. However, the licensing department did not intend to update the TS page to state the plugging criteria for sleeves. Evidently, the established SG tube sleeve plugging limit is not known within all responsible groups and unwarranted SG tubes had been plugged. This item will remain open pending the update of the appropriate TS page to include the SG tube sleeve plugging criteri (Unresolved Item 336/86-24-01)

3.2 Remote Eddy Current Data Collection ET equipment operator's are responsible for proper equipment calibration, setup and collection of ET dat For Millstone Unit 2 SG's, an in line calibration standard had been designed in accordance with ASME Code requirements. An in line standard is readily accessible for data collec-tion adjustments which must be performed at the beginning and end of every tape, every four hours, at every change of a test parameter and whenever deemed necessary by technicians. During observation of ET data acquist-tion, the inspector verified these adjustments were being performed and that a proper scan speed of less than or equal to 14 inches per second was being use The site ET data acquisition procedure emphasized the high level of radiation expected during completion of work within the SG's. One field change required "all personnel who enter (the SG) channel head' to

" demonstrate their proficiency in a full scale mockup" of all work activi-ties to be performed. The work rehearsal included use of full protective clothing. A walk-through of the SG mockup and training facilities supported the inspector's conclusion that the utmost care is being taken to minimize personnel exposures to radiation and contamination during SG tube Inservice Inspection .3 Data Analyses lhe types of flaws typically identified in Millstone Unit 2 SG tubes include (1) pitting (small volume flaws), (2) large volume flaws, and (3)

distorted tube sheet signals (DTS). During this outage, the major source of indications has been pitting, attributed to sludge within the kidney-

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shaped regions during operation of the SG's. During the 1985 outage, an experimental chemical cleaning process had been performed in the steam generators to reduce tube corrosion. Chemical cleaning has increased eddy current detection capabilities, but the effects of the cleaning on tube degradation had not been evaluated at the time of this inspectio Data analyses at Millstone Unit 2 is performed by primary and secondary analysts to provide for an independent, second party review of indica-tions. The inspector reviewed the independent analyses process and also verified that the frequencies used to complete the Full Length and First Support Programs were in accordance with SORC/PORC approved procedure .4 Quality Assurance / Quality Control Activities During this outage, Quality Control personnel attempted 100% verification of Combustion Engineering examination data to respective steam generator tube locations. Verification is accomplished by reviewing video tapes of the steam generator template and eddy current probe entry location for individual tube examinations. The intent of the QC verification of ET data and, tube location is to (1) assure completion of each ET Program scope and (2) to reduce potential radiation exposures and outage delays associated with occasional mislabeled ET data. The inspector reviewed the taping process, QC tape review and subsequent resolution of QC areas of concern for certain tube examinations. Those areas reviewed were found acceptable. From this in process audit, it was apparent that the QC indirect inspection of the ET would provide an adequate means of monitoring vendor activities and should satisfactorily meet management goal .5 Summary of Observations and Findings Based upon the above observations, it appears the licensee's activities meet Technical Specification surveillance requirements, including the random sample tube examinations (Full Length Program) and known problem area examinations (First Support Program). The data acquisition and analyses observed was performed in accordance with site administrative procedures, including the appropriate field changes. Supplemental administrative policies have been established to train personnel to i minimize radiation exposures and to verify completion of surveillance activities. However, to accurately determine operability of Millstone Unit 2 steam generators, the licensee should formally update current TS pages to reflect the established licensing agreements regarding SG sleeve plugging limit .0 Unresolved Items

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Unresolved items are matters about which more information is required in order to ascertain whether they are acceptable items, violations or deviations. Unresolved items are discussed in section 3.1 of this report.

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5.0 Exit Meeting The inspector met with licensee representatives (denoted in paragraph 1)

at the conclusion of this inspection on November 7,1986. The inspector summarized the purpose of this inspection and discussed the relevant findings. At no time during this inspection was written material provided by the inspector to the licensee.

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Attachment 1 REFERENCE DOCUMENTS FOR INSPECTION REPORT 50-336/86-24

- NU drawing no. 25203-29473 sheet 3, Tube sheet pattern, MS Steam Generator No. 2, Hot Side

- MP2 - ISI004, " Procedure for Multi-frequency Eddy Current Examination of Non-ferromagnetic Steam Generator Tubing using MIZ18 Equipment" and subsequent field change no.'s MP2-ET-001,.......

- USNRC Regulatory Guide 1.83, Revision 1

- ASME B&PV Code, 1977 Edition with the Winter of 1978 Addenda,Section XI

- RP S305-21 Final Report on CHEMICAL CLEANING OF MILLSTONE 2, dated December 1985

- MS2 FSAR Sections on Reactor Coolant System and Steam Generator

- Millstone Unit 2 Technical Specification section 3/4.4.5 Steam Generators

- 1985 Annual Report for Millstone Unit 2

- Various Northeast Nuclear Energy Company correspondence and NRC Division of Licensing letters

- Portions of Data Tape No.'s 2H3; 2H-10; 1H-28; IC16; 2H-9; 2H-8; and IC-9

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