IR 05000438/1986010

Insp Repts 50-438/86-10 & 50-439/86-10 on 861216-18. No Violations Noted.Major Areas Inspected:Maint Program for post-tensioning,employee Concern in Structural Concrete & Previously Identified Enforcement & Unresolved Items

ML20207T475
Person / Time
Site:	Bellefonte
Issue date:	02/24/1987
From:	Conlon T, Harris J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20207T457	List: IR 05000438/1986010 ML20207T456
References
50-438-86-10, 50-439-86-10, NUDOCS 8703240053
Download: ML20207T475 (5)

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UNITE 3 STAT ES

, /g6n atog.o NUCLEAR REGULATORY COMMISSION y* REGION il g ,g 101 MARIETTA STREET.N * * AT L ANTA, GEORGI A 30323

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Report Nos.: 50-438/86-10 and 50-439/86-10

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Licensee: Tennessee Valley Authority 6N38 A Lookout 1101 Market Street Chattanooga, TN 37402-2801 Docket Nos.: 50-438 and 50-439 License Nos.: CPPR-122 and CPPR-123 Facility Name: Bellefonte 1 and 2 Inspection Conducted: December 16-18, 1986 Inspector: bMdm 2 2tr f7 Date Signed J.R.Hayris Approved by: (C//

T. E. Conlon, Section Chief

/ f -;u/ 97 Date Slgned Engineering 8 ranch Division of Reactor Safety i

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SUMMARY Scope: This routine, unannounced inspection was conducted in the areas of maintenance program for post tensioning, employee concern in structural concrete, a previously identified enforcement item, previously identified unresolved items concerning procedures and installation of anchor bolts and an inspector follow-up item on compressive concrete strength in anchor failure area Results: No violations or deviations were identified, i

8703240053 870226 PDR ADOCM 05000438 0 FDR

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REPORT DETAILS Persons Contacted Licensee Employees

• J. E. Blackburn, Marager QA

• T. Floyd, Nuclear Engineer

• W. Gandy, Mechanical Engineer

• S. Johnson, Site Quality Manager

• D. Nixon, Quality Control Supervisor

• R. Roy, Civil QC Inspector

. *K. Turner, Engineer Associate

• T. West, Site Licensing Engineering Aide D. Norris, Site Civil Engineer Other licensee employees contacted included construction craftsmen, and engineers.

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NRC Resident Inspector

• J. W. York, NRC Resident Inspector

• Attended exit interview Exit Interview I

The inspection scope and findings were summarized on December 18, 1986, with those persons indicated in paragraph 1 above. The inspector described the l areas inspected and discussed in detail the inspection finding No I dissenting comments were received from the license The licensee did not I identify as proprietary any of the materials provided to or reviewed by the l inspectors during this inspectio . Licensee Action on Previous Enforcement Matters i (Closed) Violation 84-09-01, Failure to Properly Evaluate and Classify NCR I 1885 As Significant and Reportable. Nonconformance number 1885 involved l numerous failures of 3/4 inch expansion shell anchors in the control

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i building M and P line walls that were not classified as significan I Failure of the anchors could lead to failure of safety systems beirg

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supported by the anchors. The failure of the expansion anchors is a repeat

! of the same problem identified in nonconformance number 1381. Noncon-formance 1381 which also involved numerous failures of expansion shell anchors in the M and P line walls of the control building and were classified as significant and reported to NRC Region !! as reportable under 10 CFR 50.55(e) criteria, s

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The inspector reviewed the licensee's response dated May 24, 1984, and corrective actions taken to avoid further noncomplianc NCR 1885 was upgraded to a significant condition and reported to the NRC under requirements of 10 CFR 50.55(e). Procedure (BNP) - (QCP) - 2.8, R13

" Bolt Anchors Set in Hardened Concrete," was revised to prohibit any future installation of SSD type anchors in concrete walls in pour number C7-3a, which included all areas identified as exhibiting high anchor failure in NCRs 1381 and 1885. BNP-QCP-10.4, R10. " Control of Nonconformances," which requires the review for significance by the construction engineers organiza-tion, has been changed to require review by an independent member of the Quality Manager's Organization. BNP-QCP-10.41, " Trend Analysis Program" was generated to assist in providing an indicator to organizations as to where project management quality level objectives are met and for determining specific areas needing investigation and/or improvement when these objectives are not met. This item is close (Closed) Unresolved Item 83-16-01, Improper Nut on an ASTM A-325 Bol Examiration of bolted connections for the main steam line supports disclosed that an unidentifiable nut was installed on an ASTM A-325 bolt. Follow-up on this item disclosed that this was due to the identification marking on the mt beinginstalled inward instead of outward where it could readily be identified. Procedures have been revised to clarify that the markings are installed outward. This item is close (Closed) Unresolved Item 83-16-02 Clarification of Procedures Regarding Correct Nuts for Bolted Connections. Follow up on this item disclosed that procedures were not specific in addressing that the nut markings should be installed outward so that the identity of the nut could readily be identified. Procedures have been revised to assure that nuts can be identified. This item is close . Unresolved Items Unresolved items were not identified during this inspectio . Independent Inspection Effort Construction Progress The inspector conducted a general inspection of the maintenance program for post tensioning. Regulatory Guide 1.35, " Inservice Inspection of Ungrouted Tendons In Prestressed Concrete Containment Structures," requires inservice inspection at one, three and five years after the structural integrity test and every five years thereaf ter. The tendons at Bellefonte have been in place for about five years and it probably will be several years before the structural integrity test is performe The NRC inspector discussed with the responsible site engineer (D. Norris) the possible need to consider a maintenance program for the tendons. The responsible site engineer (D. Norris) indicated he would discuss the need for an inservice maintenance program with responsible design engineers in Knoxvill __ _;

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Within the areas examined no violations or deviations were identified.

6. Inspector Follow-up Items (IFI)

(Closed) Inspector Follow-up Items, 438/81-19-01 and 439/81-19-01, Compressive Concrete Strength in Anchor Failure Area Follow up of this item showed NCR 1381 was initiated on February 13, 1981, as a result of a high rate of anchor failures in a control building wal Evaluation of NCR 1381 by the licensee resulted in the problem being classified as significant and reportable to the NRC under 10 CFR 50.55(e)

criteria. The licensee reported the item to the NRC on March 10, 1981 and sent four evaluation reports to the NRC dated April 9,1981, July 27,1981, November 9, 1981 and January 29, 1982. The reports indicated that the problem was in the H and P line walls between column lines C8 and C10 at elevations 680 to 687. The reports showed that six concrete cores were taken in the area of excessive $50 type anchor failure areas and that three additional cores were taken from an adjacent area where the SSD anchors were acceptable. Visual examination of cores from the failure area revealed that a one inch layer near the surface was a different color than the remainder of the core. The color difference indicated a significantly different degree of hydration near the surface. Test results on these cores showed that the outer three inches of the concrete was slightly below design strength. Tests of the three cores taken from the area that was acceptable were above design strength. Proposed corrective action in NCR 1381 required that all 3/4 inch $50 anchors in the M and P line walls between column lines C8 and C10 and between elevation 680 and 687 be removed and replaced with wedge bolt or grouted anchors. The wedge bolts and grouted anchors are embedded deep enough to ensure that the reduced strength of the concrete surface will not affect their capacit Examination of proof test reports for all anchors installed on the entire project during October, November and December of 1980, showed that the failure rate for the remaining SSD anchors were within specification. Evaluation by design engineers showed that the slightly understrength surface condition will have no detrimental effect on the structural capacity of the walls. Future installation of $50 anchors in the H and P line concrete walls is prohibited. This item is closed.

7. Employee Concern, Discussion And Finding The following employee concern was reviewed, "Honeycombing" of concrete occurred in the auxiliary buildin (1) Concern A concern was expressed indicating that honeycombing occurred in the coaling at the 610 elevation A-12 area R line and the 610 elevation of wall A-6 in the auxiliary buildin _ _ - _ _ _ _ _ _ . _ _ _ - _ - _ _ _ _ _ - _ _ _

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(2) Discussion The inspector addressed a similar concern expressed by the alleger in inspection report number 50-438/84-09 and 50-439/84-0 Information provided by the alleger at that time indicated that Red Head self-drilling expansion anchors (SSD anchors) were sinking into the concrete when installed in concrete honeycom The alleger identified the area of concern as the A-12 wall at the

'R' column line on the 610 elevation in the auxiliary buildin As a result the inspector examined the entire A-12 wall and adjacent walls on 610 elevation in the auxiliary buildin No honeycomb was visible and examination of documentation showed that no honeycomb repairs had been made. Some small air pockets due to accumulation of air bubbles at the formed surface were visibl These are considered to be of a cosmetic nature and do not have any structural significance. Examination of pull tests on $50 anchors supporting pipe hangers in the A-12 wall near the "R" column line showed no failure of SSD anchors set in concrete in the A-12 wall . During the inspection the inspector did verify that there was a problem with installation of $50 anchors in the concrete in the M and P line walls between the control building and auxiliary building at elevation 680 and 68 This was identified by the licensee in NCR 1381 and reported to the NRC under 10 CFR 50.55(e) criteria. Coros were taken in the area of SSD anchor failures. Test results of the cores showed the outer three inches of the concrete was slightly below design strengt Corrective action included removal of all 3/4 inch $50 anchors in the M and P line wall and replacement with longer wedge bolt or grouted anchors. Evaluation by design engineers showed that the slightly under strength surface condition would have no I detrimental effect on the structural capacity nf the wall Results of this inspection were supplied to the alleger. After reviewing the inspectors report, the alleger supplied additional information indicating thst the honeycomb problem was in the ceiling not the wall. He ',ndicated A12 was the area of location along with R line at the ',10 level. He also indicated that wall A-6 in the auxiliary butid:ng at elevation 610 contained honeycomb and the grain of the concrete was powder In following up on this additional information the inspector examined the concrete in the ceiling and wall A-6 in the auxiliary butiding at elevation 610. Examination of the concreto showed no '

evidence of honeycomb. Some small holes (tiny voids) were observed which are due to air voids occurring at the form surfac These are considered as cosmetic defects only. The inspector also noted that some small patch repairs had been made to the concrete as a result of minor defect Finding h allegation was not substantiate No evidence of honeycomb was identified in the referenced areas,