IR 05000277/1993016

Insp Repts 50-277/93-16 & 50-278/93-16 on 930712-15.Actions Taken to Strengthen Perceived Weaknesses Noted.Major Areas Inspected:Erosion/Corrosion Program,Per GL 89-08

ML20056E357
Person / Time
Site:	Peach Bottom
Issue date:	08/05/1993
From:	Gray E, Mcbrearty R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20056E351	List: IR 05000277/1993016 ML20056E350
References
50-277-93-16, 50-278-93-16, GL-89-08, GL-89-8, NUDOCS 9308230229
Download: ML20056E357 (9)

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U.S. NUCLEAR REGULATORY COMMISSION '

REGION I

REPORT NOS.

50-277/93-16-l 50-278/93-16 l

DOCKET NOS.

50-277 50-278

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i LICENSE NOS.

DPR-44

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DPR-56 i

J LICENSEE:

Philadelphia Electric Company P. O. Box 195 Wayne, Pennsylvania 19087-0195 FACILITY:

Peach Bottom Atomic Power Station, Units 2 and 3 INSPECTION AT:

Delta, Pennsylvania l

INSPECTION DATES:

July 12-15,- 1993

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8b M 4 /ffJ INSPECTOR:

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R. A. McBrearty, Reactor (digineer D6te Materials Section, EB, DRS APPROVED BY:

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v'y [ /97J E. H. Gray, Chief U Date Materials Section, EB, DRS i

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9308230229 930810 E!

PDR ADDCK 05000277 Id l

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Areas Inspected: An announced inspection was conducted of the licensee's erosion / corrosion (FJC) inspection program to ascertain that activities relative to the long-term E/C monitoring program are being accomplished in accordance with Generic Letter 89-08 and licensee commitments and procedures.

The program and its implementation are generally good. The engineering staff Results:

responsible for E/C program development and implementation, although small, is well qualified and knowledgeable of the activities for which they are responsible. Actions have been taken to strengthen perceived weaknesses in the program and a consultant has been contracted to revise the program and update it to the latest industry guidelines and regulatory requirements.

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DETAILS

l 1.0 BACKGROUhT Concerns regarding erosion and corrosion in balance of plant piping systems has been heightened as a result of the December 6,1986, feedwater line rupture that occurred at Surry

Unit 2. This event was the subject of NRC Information Notice 86-17,Bulletin 87-01 and I

Generic Letter (GL) 89-08. The GL specifies that all licensees provide assurances that a program, consisting of systematic measures to ensure that erosion / corrosion (E/C) does not lead to degradation of single and two-phase high energy carbon steel systems, has been implemented.

An effective E/C program will detect erosion of high energy carbon steel piping before the

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pipe wall is significantly reduced below the design or piping code minimum wall thickness.

l This program should reduce risk to the plant staff and prevent unnecessary system transients thereby contributing to the safety of the public.

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Each Philadelphia Eectric Company nuclear facility has an established long-term erosion / corrosion monitoring program. The programs are intended to assure that the structural integrity of all high-energy single-phase and two-phase carbon steel systems is maintained. The inspection procedure (ultrasonic examination) used for the detection of erosion / corrosion damage in piping systems is common to each of the facilities.

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s Carbon steel piping that is damaged by E/C is replaced with 1 % % chromium, % %

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molybdenum alloy steel which is more resistant to E/C than is carbon steel. The material f

upgrading is covered in the E/C program for Peach Bottom and Limerick and is documented

in Piping Specifications P-300 and M-300. The material upgrade, additionally, is validated l

by a 50.59 Safety Evaluation for each facility.

2.0 INSPECTION OBJECTIVE I

The inspection was conducted to determine whether licensee activities relative to the long-term erosion / corrosion monitoring program are being accomplished in accordance with NRC requirements and licensee commitments and procedures.

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i 3.0 EROSION / CORROSION PROGRAM RESPONSIBILITIES

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3.1 Corporate Engineering

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The Nuclear Engineering and Services Department (NESD) responsibilities for the E/C

program are delineated by Specification M-721, Revision 0, " Specification for the Peach

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I Bottom Atomic Power Station Unit 2 & 3 Program for Monitoring Pipe for Wall Thinning

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Due to Erosion / Corrosion." Those responsibilities include identifying and prioritizing systems which are susceptible to E/C, selecting piping locations for examination, establishing i

screening and acceptance criteria and establishing sample expansion criteria. Engineering is i

also responsible for the evaluation and disposition of inspection results which do not satisfy

screening or acceptance criteria and determination of the frequency of subsequent l

inspections.

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The NESD responsibility for selecting and prioritizing the E/C program scope is supplemented by a consultant contracted by the licensee. The consultant has been mandated i

with revising the E/C program and the development of system susceptibility criteria.

Additionally, the consultant has been charged with identifying which of the potentially

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susceptible systems should be modelled with the Electric Power Research Institute (EPRI)

developed CHECMATE computer code, and to bring the E/C program up to the latest industry guidelines and regulatory requirements. The program revision is scheduled for i

I completion by November 1993. System modelling at Peach Bottom and Limerick is scheduled to be performed in parallel so that CHECMATE predictive information is expected

to be available to assist in line evaluations during the upcoming Peach Bottom Unit 3 i

refueling outage. The particular consultant to PECo has performed a similar function at

other nuclear facilities, thereby giving PECo the benefit of experiences at those other plants.

i 3.2 Site i

The Peach Bottom Atomic Power Station is responsible for implementing the Peach Bottom l

Station E/C program. Station responsibilities include planning and scheduling the inspection of locations identified by NESD, notifying NESD of inspection results, implementing NESD

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recommended corrective actions, and controlling statioa E/C dodumentation.

The NDE Services Section of the Nuclear Quality Assurance (NQA) Department has the responsibility for inspection of piping associated with the Peach Bottom E/C program. In addition to the inspection of pipe identified by.NESD, the NDE Services Section i

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responsibilities include the training and certification of, or assuring the certification of l

personnel performing inspections, documenting inspection results, notifying the Station of inspection results and controlling the NQA crosion/ corrosion documentation including inspection results.

4.0 INSPECTION ACTIVITIES

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4.1 General Requirements The licensee's primary inspection method incorporates ultrasonic examination techniques for measuring pipe wall thickness. Additionally, Specification M-721, Revision 0, permits the use of visual inspection, when possible, to determine the extent and location of wall loss.

The wall thickness may then be measured using an ultrasonic examination technique on the areas of concern.

After the initial piping selection is made and prioritized by NESD, the inspection sample is transmitted from NESD to the Peach Bottom Station cognizant engineer. The Station notifies the NDE Services Section of which locations are to be inspected via a Maintenance Request Form (MRF). Inspection results are reported to the Station for its review and then are submitted by the Station to NESD via an Engineering Work Request (EWR) for analysis.

Inspection results which are below the allowable wall thickness (Ta) are reported via a nonconformance report (NCR) to NESD.

When inspections are in progress during an outage, the NDE Services Section of NQA provides the licensee's inservice inspection (ISI) vendor with the inspection locations. At Peach Bottom, the ISI vendor performs the erosion / corrosion inspections. The appropriate

grid pattern or banding pattern is applied as specified by the licensee's procedure NDE-6,

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Revision 2, " Ultrasonic Examination for Erosion / Corrosion." Datum points to locate the grid patterns are permanently marked on the pipe using low stress stamps as required by the latest revision of NDE-6. The lack of permanent reference points was identified as a programmatic weakness during a 1992 NRC erosion / corrosion inspection at the Philadelphia Electric Company's Limerick. Generating Station. Procedure NDE-6 provides well defm' ed guidance for establishing grid patterns including sketches showing the various piping configurations and the grid or banding pattern required for each geometry.

4.2 Erosion / Corrosion Program Specification M-721 provides detailed information regarding the selection of areas requiring E/C inspection. The specification identifies selection criteria that is considered by the NESD responsible engineer who makes the selection. Parameters that must be considered include water chemistry, temperature, flow path geometry, flow velocity and material composition.

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Information regarding the Units 2 and 3 E/C program such as specific areas and lines that j

are included in the program, single and two-phase flow inspection schedule, acceptance criteria and parameters effecting erosion / corrosion is included in eight appendica to M-721.

Appendix 8 contains specific data regarding the following:

Effects cf Oxygen on E/C;

Single-Phase Flow E/C Geometry Factors;

• Influence of Flow and Temperature on E/C in Single-Phase Flow;

Influence of Temperature on E/C in Two-Phase Flow; and

Effect of Steam Quality on E/C in Two-Phase Flow.

• The above is intended to be used for selecting and prioritizing systems, areas and lines in the E/C program.

As discussed earlier in this report, the licensee is in the process of revising its E/C program and willincorporate the use of the CHECMATE computer code for selecting, prioritizing and updating the E/C program at Peach Bottom. Presently, those tasis are performed

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j manually using the information provided by M-721.

5.0 INSPECTION ACTIVITIES The licensee's ISI contractor performs the erosion / corrosion inspections during refueling l

outages at the Peach Bottom facility. Prior to an outage, the NESD responsible engineer i

must provide the site with a list of areas and locations that he has scheduled for inspection during the particular outage. The NESD list is used by the site E/C engineer to prepare an outage schedule of inspections. Prior to performing the inspection, the location of each inspection item is verified by a walkdown inspection and the correct item is marked. That aids vendor inspection personnel in assuring that they are inspecting the appropriate item.

Information provided to inspection personnel includes nominal pipe size, nominal and

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i minimum wall thickness, allowable wall thickness and an isometric drawing showing the location on the system of the inspection item.

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Thickness readings are recorded using an ultrasonic data logger that stores the readings until the data are loaded into a personal computer. The use of a data logger for E/C inspections has become a standard practice for the industry. After loading the data into the computer, l

l the information is recorded on a computer disc and on a hard copy report which is submitted l

i for review to the licensee's E/C engineer.

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5.1 Data Review and Processing

The data review process begins at the inspection site when the tecimician confirms the data in l

i the data logger. The hard copy report is reviewed by the vendor's data reviewer before it is submitted to the licensee where a review is performed by the licensee's E/C engineer.

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Data representing E/C inspections that were performed during the 1992 Unit 2 refueling outage were reviewed by the inspector. Those results showing minimum measured wall

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thickness below the allowable thickness identified by the program were selected for review to j

ascertain that each was analyzed and dispositioned in compliance with Specification M-721.

All of the selected data were properly dispositioned as confirmed by the related i

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noncompliance reports. Some of the items were replaced during the outage and others are

scheduled for replacement during a subsequent refueling outage. Those items that are

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scheduled for later replacement are accompanied by documentation supporting the decision to i

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defer the replacement.

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During the 2R09 outage, erosion / corrosion inspection of 100 areas was scheduled. The

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j inspection results required a sample expansion of 33 additional areas. Based on the t

inspections, approximately 5' of carbon steel piping was replaced in Area 5 (Main Steam

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Drain), and approximately 40' of carbon steel piping was replaced at three locations in

Area 11 (Off Gas Steam Drain). The replacement piping is fabricated of P-11 material

l (1%% chromium, %% molybdenum).

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1 6.0 PROGRAM STRENGTilS AND WEAKNESSES Overall, the erosion / corrosion program at Peach Bottom is a generally compretiensive progam for monitoring E/C in high energy piping systems.

l Two areas where improvement can be made are the calculation of erosion rate and remaining

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component life, data trending, and the selection and prioritization of inspection areas and locations which are presently performed manually. Also, the Chesterbrook NESD staff responsible for the E/C program is currently comprised of one engineer. The situation has

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been recognized by the licensee and an experienced consultant has been contracted to, among

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other things, initiate the use of CHECMATE, the EPRI developed predictive computer

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j model. Additionally, the consultant is to develop system susceptibility criteria, identify

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which of the potentially susceptible systems should be modelled with CHECMATE and to update the program to the latest industry guidelines and regulatory requirements. Regarding the lack of backup personnel on the NESD E/C staff, the inspector was advised that the licensee is in the process of adding a second individual to the E/C staff at Chesterbrook. It was obvious during this inspection that the Station and Chesterbrook engineers work closely together and each is capable of performing many of the E/C duties of the other.

Several areas were noted where the E/C program has been improved or actions are in progress to add program enhancements. Two EPRI personnel, expert in the area of erosion / corrosion, visited the Philadelphia Electric Company at the licensee's request to

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l review and provide constructive comments about the E/C program at Peach Bottom and I

Limerick. The licensee participates in industry organizations such as the CHEC/CHECMATE Users Group (CHUG) and encourages E/C staff attendance at CHUG meetings and at EPRI sponsored training on the use of CHECMATE. The PECo E/C staff also attended the NRC sponsored E/C workshop held in February 1993. Provisions contained in procedure NDE-6 regarding the use of permanent datum points for establishing inspection grids on pipes, and the clear, de5nitive instructions regarding the layout of l

inspection grid patterns on various piping geometries are further evidence of the licensee's desire to produce a strong program for monitoring erosion / corrosion at its nuclear facilities.

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Conclusions The Philadelphia Electric Company has an established long-term erosion / corrosion monitoring program. Apparent weaknesses in the program have been recognized by PECo and steps have been taken or are being taken to strengthen those weaknesses. The governing specification at Peach Bottom identifies responsibilities of the E/C staff at Chesterbrook and at the site. The E/C staff, although small, is comprised of engineers who are knowledgeable in their areas of responsibility, and are cognizant of industry E/C problems. Participation in industry organizations and attendance by its staff at related functions is encouraged by the licensee.

7.0 EXIT MEETING The inspector met with licensee representatives (denoted in Attachment 1) at the conclusion of the inspection on July 15, 1993. The inspector summarized the scope and findings of the inspection which were acknowledged by the licensee. The licensee did not disagree with the findings of the inspecto._.

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ATTACHMENT 1 Eersons Contacted

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t Philadelohia Electric Comoany

• R. J. Blomquist Assessor / Nuclear Quality Assurance

• G. D. Edwards Plant Manager

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• R. M. Melnick Nuclear Support, Chesterbrook Engineering

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• J. Mitman Manager, Component Engineering i

• T. Niessen Director, Site Engineering

• G. J. Ruf Component Engineering, Site Engineering

• R. Smith Regulatory i

• J. Verner ISEG i

J U.S. Nuclear Regulatory Commission

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• F. Paul Bonnett Resident Inspector

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• H. R. Abendruth Atlantic Electric Site Representative j

• R. B. Knieriem Delmarva Power Site Representative j

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