IR 05000275/1987005

Insp Repts 50-275/87-05 & 50-323/87-05 on 870112-16.No Noncompliance or Deviations Noted.Major Areas Inspected: Followup of NRC Technical Audit Branch Rept on Allegation Re Flat Spot on Reactor Coolant Piping in Unit 1 Containment

ML20210S065
Person / Time
Site:	Diablo Canyon
Issue date:	01/28/1987
From:	Burdoin J, Mendonca M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
Shared Package
ML20210R985	List: IR 05000275/1987005 ML20210R982
References
50-275-87-05, 50-275-87-5, 50-323-87-05, 50-323-87-5, NUDOCS 8702170554
Download: ML20210S065 (6)

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i .U. S.' NUCLEAR: REGULATORY COMMISSION

REGION V

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Report Nos., 50-275/87-05, 50-323/87-05

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, .. Docket No ~50-275, 50-323'

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License Nos.' DPR-80, DPR-82'

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' Lic'ensee~:

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. Pacific Gas and Electric-Company /'

77..Beale Street, Room 1451

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San Francisco, California 94106

. Facility Name: Diablo Canyon Units-1 and 2 Inspection at: Diablo Canyon Site, San Luis Obispo County, CA

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Inspection Condu4ed- Jan y 12 6, 1987

. Inspector: 4 $-

Btfrdoin, Reactor Inspection

/ f f7 D&te Sig~ned

~ Approved by: '\ 1 M*# /#7 M. M. Mendonca, Chief, Reactor Project Section I Date Signed Summary:

Inspection during period of January 12-16, 1987 (Report Nos. 50-275/87-05 and 50-323/87-05 Areas Inspected: An unannounced inspection by one regional inspector of followup of NRC's Technical Audits Branch report on an allegation concerning a flat spot on the reactor coolant piping in Unit 1 containment; of the design changes,.and modification; and an independent inspection of different vital areas and equipment in the plant. Inspection Procedure Nos. 30703, 37700,

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71707, and 92701 were used as guidance for the inspectio Results: No items of noncompliance or deviations were identified.

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i 8702170554 870129 PDR ADOCK 05000275 0 PDR

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DETAILS

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< 1. . Individuals Contacted 1 Pacific Gas and Electric Company-(PG&E)

• R. C. Thornberry, Plant Manager

• T. L. Grebel, Regulatory Compliance Supervisor R. D. Etzier, Construction Superintendent A..Taggart, Director, Quality Support QA

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L.- F. Womack, Operations Manager

'H. W. Karner, Rate Case Coordinator R. M. McVicker, QC Inspector, Mechanical D. R. Geske, Verification Planning Group Supervisor D. A.-Gonzalez, NDE Specialist D. R. Bell, QC Supervisor, General Construction M. E. Leppke, Project Engineer, General Construction

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T. E. Pierce, General Construction QC Engineer S. J. Foat, Power Production Engineer A. W. Novak, Mechanical Engineer

, Various other engineering and QC personnel l

• Denotes attendees at exit management meeting on January 16, 198 <

In addition, NRC Resident Inspectors attended the exit management meetin . Area Inspection An independent inspection.was conducted in the Turbine and Auxiliary Buildings. The equipment spaces inspected included: Five Emergency Diesel Generator Rooms, Units 1 and .Six 4160 Volt Switchgear Rooms, Units 1 and Six Battery Rooms, Units 1 and Six 480 Volt Vital Bus Rooms, Units 1 and Two Cable Spreading Rooms, Units 1 and Two Hot ~ Shutdown Panel Areas, Units 1 and Turbine Building, Elevations 85' and 140', Units 1 and Two 480 Volt Laad Center Areas, Units 1 and Combined Two-Unit Control Room, Units 1 and Housekeeping and equipment status appeared to be acceptabl No violations of NRC requirements were identifie _ - _ _ _ _ - _ _ _ - _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

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f 3. (Closed) 50-275/BD-04-01, Followup'on Handling of Flat Spot on a Large 36 Inch Diameter. Pipe (Closed Allegation Nos.-55, 161, and 221).

The Technical A'dits u Branch'in their memorandum of August 16, 1985 brought to Region V's attention that an alleger contends he had made an_

allegation to Region V personnel that had not been resolved by the NRC. % <

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The alleger had identified a flat spot on a large pipe about 36 inches in ,

diameter with a wall thickness of 2.15 inches in Unit 1 containment and his concern ~was pipe wall thickness. -He'~ assumed the pipe would have a thinner wall' dimension in the area of.the' flat spo The alleger further ~

contends that the license'e's' response-to the NRC on this issued referred *

to a flat spot on a 10 inch pipe with a wall thickness of 1 inch, and his concern of the flat spot on' f e 36 inch diameter was not addresse It is the objective of this report to address the concern of a flat spot on i the 36 inch diameter pipe' .

The original source document was reviewed and it was determined that part of the alleger's complaint was of a welding flaw on a 10 inch pipe off the cold leg pipe from reactor coolant pump 1-2. The source document ,

also reveals that the alleger identified a flat spot on a 36 inch t diameter pipe in the area (adjacent to and within approximately six feet)

of the 10 inch pipe. The only 36 inch diameter pipe in this area, is the reactor coolant system crossover pipe from steam generator 1-2 to the '

suction of reactor coolant (RC) pump 1-2. It is assumed that the flat -

spot the alleger was referring to is on the crossover pipe section to RC ,*

pump 1- During the design re-verification program for Unit 1, the Stone and Webster Engineering firm made an independent audit of the Reactor Coolant f'$

System (RCS) at the Diablo Canyon plant. This independent review involved a detailed visual examination of the Reactor Coolant System piping. All four loops of the primary system were inspected. A team of 3 to 4 auditors required a period of approximately two months from early , 'p September 1982 until the middle of November 1982 to complete their -

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hand-over-hand inspection of RCS piping surfaces. This type of an g .,

inspection involves visual examination of every square inch of the pipe T 'l ,

surface for ' deficiencies. All pipe surface deficiency such as gouges, y~

grinding marks, file scratches, arc strikes, weld splatter, rust, etc., '

were identified and documented. Following the inspection, the list of I'

deficiencies was turned over to the licensee who prepared minor variation reports (MVR) M-4405, M-4415 and M-4420 to correct / repair the deficiencies found by the Stone and Webster auditors. The repairs of the deficiencies were made by the Pullman Powers Products Company, the mechanical contractor on the site. The contractor's quality control ,

group followed the repair work and signed for the final inspection of the . 1 repairs. The licensee mechanical field engineers performed an 7, I independent visual verification of the completed repairs of the deficiencies. Following the completion of the repairs of the ,

deficiencies, the RCS pipe was washed with domineralized water and swab tested to determine the chlorine / fluoride content before the -

installation of the reflective insulation. Both of these processes; washing of the pipe and installing the insulation were followed and documented by general construction quality control inspector _ _ _ _ _ _ _

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Stone a'nUWetister's) audit of the' Reactor . Coolant System identified severaf tGas where handling lugs and fitup clips'had been removed b S grinding but had not'been liq'id u penetrant,in'specte MVR-4405 was

,' - / d_ 1 prepared to require all;su'ch areas where removal?by grinding had been

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accomplished be examined with liquid ;Any rejectable >

a - - ~indicatior.s.were to be' removed and/o.r penetrant repaired in accordance with 4approvedjrocedureswhichrequiredultrasonicmeasurementofpipe; wall

,~,IGT r tnickness.' A number of such grinding removal areas were found on RC loop

.2 41- The inspector examined in-detail MVR-4405 and the associated y

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. completion certifications and documentation. These records and documents  ;

7.[ - appeayed to be in orde ,

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j7 Stone and Webster examination of the crossover leg of reactor coolant j' sys, tem loop 1-2 also.identif' five deficiencies. Three rust. areas, one N '

cavfty (5/16"

x 3/16" x 1/16" oeep) on welded attachment removal area, and adjacent gouges (two) approximate four inches in length. These ~

de'ficiencies were corrected under MVR 4415. The repair measures for the rust' areas included remove by wire brushing-with a-stainless steel brush l i"j and cleaniai necessa,ry using demineralized water or acetone. -The '

, documentation for the repairs of the cavity-and gouges discrepancies indicates the areas were tapered and blend by grinding, the removal areas were tested with liquid penetrant and were ultrasonically tested to determine the wall thickness.

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The inspector # examined in detail MVR 4415 and 4420, and the associated

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repair. completion certifications and documentation. The inspector also L examined the' docume'atation certifying the washing of the pipe and the installation of the sflective insulation. These records and

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doc,umentation

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appe,ared to be in order and acceptabl ~

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) The Sto6e and Webster audit of loop 2 crossover pipe did not identify any i , flat spots as discrepancies. A discussion with the licensee's engineer

,a who coordinated tne $ tone and Webster audit of the RC system piping

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stated that any flat' spots discovered by these auditors would have been

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by these auditors'as discrepancie ~r Following the completion of installation of the reflective insulation and

< -in the spring of 1983, it was necessary to remove some of the insulation b i to make pipe girth weld baseline thickness measurements. It was in this b /

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time frame that LER 83-004 which 41dentifled four gouges made with i ,, grindirig wheel or rotary file'on RCS piping loop 1-3 was filed with NR '

It was concluded that these gouges'were intentionally caused by persons unknown. This issue was addressed in Inspection Reports

'a 83-17/83-20/83-21/84-1 <j .

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r To ensure there was no additional damage to the reactor coolant piping, p } Quality Control Inspection Plan (QCI)83-414 date June 30, 1983 was e developea to require a 100 percent inspection of the piping surfaces for Y/ those portions of the Unit 1 Reactor Coolant System were reflective insulation had been rerr;oved to facilitate making pipe girth weld baseline

</w,a'f- thickness measurements. However, it was decided to remove all of the r( '* reflective insulation from the primary system piping and perform a

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/ hand-over-hand visual inspection of.100% of the Reactor Coolant System piping surface. This work was done during the summer of 1983. This J

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inspection of the piping surfaces for damage also identified and documented any deficiencies such as weld splatter, arc strikes, gouges, rust spots, paint residue, etc. Thic QCI also required correction of all deficiencies found, and cleaning of pipes surface with demineralized water or acetone prior to the reinstallation of the reflective insulation. The inspector examined in detail the QCI 83-414 and associated documentation for the accomplishment and completion of the

,. above described work. This documentation appeared to be in order and i acceptabl The hand-over-hand inspection of loop 1-2 crossover pipe identified three deficiencies; tightly adhering weld splatter on inside radius below weld WIB-RC-2-/4 on the 90 degree elbow, tightly adhering weld splatter on the 20 degree elbow above weld WIB-RC-2-B, and pipe support / restraint clamps on both elbows were not removed for final cleaning. The inspector examined nuclear plant problem report (NPRR)'s DC1-83-QC-P0 257, 258, 259, 266, and 298 for correcting these deficiencies. The corrective measures appeared to be acceptable and the documentation appeared to be in order. It is noted that this hand-over-hand inspection of the loop 1-2 crossover pipe also did not identify a flat spot on this portion of the RC pipin A discussion with the licensee's QC inspector that supervised this hand-over-hand inspection of the RC piping in the field stated that any flat spots found during inspection would have been documented as discrepancie The license to ensure no damage was done to the reactor coolant system piping surface following the correction on any deficiencies and immediately prior to reinstallation of the reflective insulation required: A visual examination of all exposed surfaces of the pipe for visible evidence of damaged and maintained a surveillance of visually accepted exposed piping until the reflective insulation was reinstalled on the pipe. To maintain visual surveillance of the exposed pipe the licensee utilized the Plant Security Force by placing guards on the pipe until the insulation was reinstalle The reflective insulation once installed under QCI 83-414 was not removed again prior to plant initial startup (April 1984) except in a few isolated cases such as the followup of allegations. In those cases, a minimum amount of insulation was removed and extreme care was exercised to ensure no damage was done to the RCS piping during the short period that the reflective insulation was off the pip The inspector examined the certification and documentation for the washing of the reactor coolant piping, and the reinstallation of the reflective insulation following the repair of the deficiencies identified during the inspection required by QCI 83-41 These records appeared to be in order and' acceptabl Summary Two complete and independent hand-over-hand (meticulous) inspections of the reactor coolant piping surfaces were performed between the fall of 1982 and end of summer of 1983. From review of the deficiencies found and repaired during the two inspections, the first inspection (Stcne and

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Webster inspection; brought out the more significant deficiencies such as

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s gouges, cavities, fi_le scratches, arc. strikes, and grinding marks while the second inspection (QCI.83-414 inspection) found mostly less

'significant' deficiencies such as arc strikes, weld splatter, paint residue? etc. .These deficiencies found by the'second inspection are all items which probably' occurred between the time the first inspection was L_ completed and the second inspection was performe T lIt'~isconcluded.thatbothinspectionsofthepipesurfaceswerevery

- thorough.'.. Neither inspection, identified a flat spot on the. surfaces of

.3 loop 1-2 of the primary system piping. Had.such a spot been' identified c' anywhere on the Reactor Coolant System piping, it would have been-t ' ultrasonically tested to deterniine pipe wall ^ thickness. It is possible that the alleger identified.as a flat spot, one of _the handling lug

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removal' grinding areas which;were addressed' earlier in this report. In

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the final analysis, the' licensee's processing of piping surfaces of the

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reactor coolant. piping during late '1982 and 1983 in preparation for e declaring 1the system operational is considered to be thorough and

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No violations'or deviations were identifie + . Design, De' sign Changes,-and Modifications ,

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The review and examination of. licensee's procedures-for processing onsite

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design, design changes, and modifications was commenced by reviewing Engineering Procedure No. 3.60N, Revision TR-59, dated August 4, 1986,

" Operating Nuclear Power Plant Design Changes." However, inspection in

. . this area was incomplete and shall be continued during a future inspectio This item will be followed as open item 50-275/323/87-05-0 , No' violations or deviations were identifie ' Exit Meeting

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The inspector conducted an exit meeting on January 16, 1987, with the

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Plant Manager ano other members of the plant staff. During this meeting,

> . 'the inspector. summarized the scope of the inspection activities and

reviewed the inspection findings as described in this report. The L licensee acknowledged the concerns identified in the repor ,

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