IR 05000456/1989016

Safety Insp Repts 50-456/89-16 & 50-457/89-16 on 890731- 0803.Allegations Unsubstantiated.Major Areas Inspected: Allegations Re NDE & Corrosion of Small Bore Piping

ML20246F152
Person / Time
Site:	Braidwood
Issue date:	08/21/1989
From:	Danielson D, Jeffrey Jacobson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20246F144	List: IR 05000456/1989016 ML20246F140
References
50-456-89-16, 50-457-89-16, NUDOCS 8908300177
Download: ML20246F152 (5)

Text

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-.U. S.;i < NUCLEAR REGULATORY; COMMISSION -

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REGIONLIII n c.au

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lReports:No.150-456/89016(DRS);50-457/89016(DRSk ' '

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Licenses No.INPF-72;lNPF-77i

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. flicensee: .. Commonwealth Edison' Company; ,' ~

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LFacility Name:. Braidwood Station, Units 1 and 2- - -

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fInspectionAt: 'Braidwood Site,;Braceville, Illinois'

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,,, 1 Inspection Conducte : : July.31 through' August'3,119891 y ;.

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g' Inspector:

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_, Approved By:-..D. H.:Danielson, Chie ~

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' Materials and Processes i 'Date <

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Section -1 .

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-  : Inspection ~. Summary

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'r,~ . ;. , ' :Inspectionlon July 31 through August 3,1989 (Reports'No. 50-456/89016(DRS);

'No.-50-457/89016(DRS))

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a Areas-Inspected: Announced'special, safety inspection of allegations

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' concerning nondestructive' examination and corrosion of:small bore pipin "

Res'ul ts:. Neither allegation was. substantiated. The. licensee's program to:

-disposition the' corroded pipe ~and the Material Traceability Verification Program had effectively resolved both issue .

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u 8908300177 890822 PDR ADOCK 05000456 n. '

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DETAILS

' Persons Contact'd. e ,

Commonwealth Ediso ,

. *R. E. Querio, Station Manage .

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• M. E. Lohmann, Assistant Superintendent; Maintenance

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• D. E. Cooper, Supervisor, Regulatory Assurance

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' *E. W. Carroll,' Regulatory Assurance

• D. E Skoza, Project Engineer

• L. W. Raney, Nuclear-Safety-

• R. D. Kyrouac, Quality Assurance Superintendent

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• Denotes those atten' ding the exit meeting on August 3, 1989. Allegations (Closed) Allegation-(RIII-88-A-0189): Concerns relating to small bore piping corrosion and examination (construction issues). Nondestructive Examination of Class 1 Pipe and Fittings

'(1) Concern The ASME Code, in general, requires that~ Class.1 piping and fittings be examined utilizing an appropriate' nondestructive examination (NDT)' techniqu As a result of material control problems, some material was installed in Class 1 applications without the required NDE. The alleger is concerned that some in' stalled material, without.the required NDE, may not have been located and properly dispositione ,

(2) NRC Review-The ASME Code,Section III, Subsection.NB describes the

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requirements for Class 1 components. Paragraph NB-3630, however, allows the designer.to apply,the requirements of Class 2 components for pipe and fittings of nominal diameter 1 inch and less. Thus, Class 1~ components with a one inch or less diameter may be installed without NDE, since this is not a requirement of Class Subsection NB further provides that NDE is not required for pipe and fittings of 2 inch diameter and less (NB-2510),

provided that reduced stress allowables are applied to the design (NB-3673).

The initial S&L piping specification (F/L-2739) did not require that NDE be performed for Class 1 components of 2 inch and less diameter, in expectation that the above exemptions would appl '

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Subsequently, the specification was revised to require NDE for this piping, however, approximately half of the piping had

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already been installed. The NRC inspector found that this issue had been dealt with in a piecemeal manner until ultimately. falling under the umbrella of the licensee's Material. Traceability Verification (MTV) Progra During.the 1982-1983 timeframe, Phillips,'Getschow (PGCo), the mechanical contractor, issued NCR Nos. 192 and 793 to deal with the installed piping. .The disposition resulted in a mixture of accepting the reduced allowables (NB-3673) and' performing NDE in place. Later.in.1983, a QA audit disclosed an additional heat of material which had not been' included in 1, the scope of-NCR Nos. 792 and 793. 'NCR'No. 1159 was. issued in August 1983 to disposition this' materia ~

<In'an effort to segregate those heat' numbers of material

- including both Class 1 (NDE performed) and Class.2 (no NDE performed) material which_ remained in storage, NCR No. 2364

- was issued in October 1984. The disposition.of this NCR wa to sort out that material which did not have NDE markings and designate it as" Class 2 or send-the material out'to have NDE performed. This_ material was' returned to stores with the proper markings and subsequently issued Lto the. field for installation. Unfortunately, when PGCo cut the pipe for installation, heat numbers were transferred thus maintaining traceability, however, the NDE markings were not consistently transferre At this. point, the licensee elected to-include the verification of NDE markings for all installed Class.1, small bore piping in their MTV progra NCR No. 5017 was issued in October 1985 to expand the MTV cut off date of September 1983 to all small bore piping installed prior to October 198 As a result of the MTV effort, all installed Class-1 piping was physically verified to have NDE markings or an NCR was issue The disposition of these NCR's was to' accept as is (per previously discussed Code exemptions) or perform the required

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ND The NRC inspector reviewed a sample of the NCR's and found them acceptabl (3) Conclusions The allegation could not be substantiated in that MTV effort examined all Class 1 installed piping for proper NDE marking Material which could not be verified to have been examined by NDE was properly dispositioned per ASME Code requirements. The NRC monitored the MTV program through completion and concluded that the program was effective in assuring that correct material was installed (NRC Inspection Report Nos. 50-456/85061; i 50-457/85057)

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Pipe Wall Corrosion-

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(1)-Concern Due to imprope'r storage, a quantity (268,000_ feet) of small bore pipe,_available for use.in. safety-related applications,

.was found to exhibit pitting corrosion. -This corrosion, in some instances was found to violate Code minimum wall thickness -

requirements. The licensee issued NCR:No.- 633. in June 1984 to address this issu The alleger is concerned with the sample size.being too small to adequately evaluate and ultimately close the issu (2) NRC Review The alleger specifically indicated that the NRC pipe wall measurement sample mentioned in NRC Inspection Report No /85061;'50-457/85057 may not have been adequate. It should be noted that the purpose of this sample was not intended to "close" the pipe wall issue. _This sample was-performed to address an allegation (NRC Inspection Report Nos. 50-456/85050; 50-457/85048) concerning the validity of-a portion of the licensee's MTV program. The licensee had already identified the subject of the; alleger's concern and had taken corrective action. The NRC sample was one af many inspections utiliz2d to monitor the licensee's MTV progra .The licensee's program to disposition NCR No. 633 consisted of four parts:

• Theoretical increase in stress

• Chemical and physical testing

• - Wall thickness measurements

• Final engineering evaluation The licensee determined that approximately 16,000 feet of the pipe in question had been installed in safety-related system The licensee selected samples of the affected pipe remaining in storage and found the wall thickness to be less than that required by Code at certain localized areas. The sample consisted of'272 segments of pipe considered to be the most affected by pitting. Out of.544 pit measurements, the deepest pit found was 0.033". This information was forwarded to S&L for evaluatio S&L modeled the notch effect stress component by assuming that the 0.033" pit existed both on the 0D and ID of the pipe a full 360 . The reduction in'section modulus was calculated assuming that the 0.033" pit was not localized but occurring over the entire OD of the pipe. From this conservative model, a stress intensification factor (SIF) was develope This SIF was then

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applied to the prior: stress analysis results for all; potentially affected piping systems. From this effort, it was determined that six locations could theoretically be over stressed. These six locations and an additional four locations were removed from the plant for conservatis The licensee also conducted a number of chemical and physical tests on the affected piping. The results of the testing concluded that all samples met or exceeded the ASTM material specification requirements for A-106, Grade B pip To further validate the initial engineering evaluation, the licensee conducted a statistically significant wall thickness sampling progra The population was defined as 28,723 pieces of three foot length (representing the average installed piece). For purposes of satisfying a 95% confidence /99% reliability criterion, 300 random samples were obtained from both material in storage and material installed in the plant. A tom of 497 locations out of 28,112 points measured (on tne 300 samples)

were found to violate the Code specified minimum wall. These samples were then evaluated against ASME Code allowable stresses and were found to be acceptabl The final engineering evaluation concluded that with the exception of the six previously discussed locations removed from the plant, all pipe installations would meet ASME allowable stress limit (3) Conclusion The allegation could not be substantiated in that the NRC did not "close" this issue based on the sample noted by the alleger and furthermore, the licensee's 28,112 measurements were statistically significant. The NRC monitored the licensee's entire program for NCR No. 633 and documented closure of this issue in NRC Inspection Report Nos. 50-456/86008; 50-457/8600 . Exit Interview The Region III inspector met with the licensee representatives (denoted in Paragraph 1) at the conclusion of the inspection on August 3,198 The inspector summarized the purpose and findings of the inspection. The licensee representatives acknowledged this information. The inspector also discussed the likely informational content of the inspection report with regard to documents or processes reviewed during the inspectio The licensee representatives did not identify any such documants/ processes as proprietar I i

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