IR 05000456/1981012
| ML20031G057 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 10/01/1981 |
| From: | Hawkins F, Hind J, Landsman R, Norton J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20031G056 | List: |
| References | |
| 50-456-81-12, 50-457-81-12, NUDOCS 8110200742 | |
| Download: ML20031G057 (6) | |
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U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT
REGION III
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Reports No. 50-456/81-12; 50-457/81-12 Docket Nos. 50-456; 50-457 Licenses No. CPPR-132; CPPR-133 Licensee: Commonwealth Edison Company P.
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%x 767 Chicago, IL 60690 Facility Name: Braidwood Station, Units 1 & 2 l
Inspection At: Braidwood Site, Braidwood, IL
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j Inspection Conducted: September 9, 10, 11, 16, and 22, 1981
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Inspectors:
J.F.Norton&
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J. M. Hinds (September 9 and 10 only)
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Gd R.B.Landsmaf(September 22only)
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Approved By:
F.
. Hawkins, Acting Chief
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Plant SystemsSection I
Inspection Summary Inspection on September 9, 10, 11, 16, and 22, 1981 Report No. 50-456/81-12;
50-457/81-12)
Areas Inspected: Observation of containment post-tensioning wo.4 activi-ties, review of post-tensioning QA implementing procedures, revies of QA r
post-tensioning records and investigation of failed bearing plate seat V157.
The inspection involved 56 inspector-hours on site by three NRC itspectors.
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Results: No items of noncompliance or deviations were identific',.
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DETAILS Persons Contacted Commonwealth Edison Company (CECO)
D. Cosaro, Project Construction Superintendent G. Marcus, Director of QA
- T. Sommerfield, QA Superintendent
- C. Gray, Structural Engineer Napoleon Steel Contractors Incorporated C. Zavada, QA Manager D. Rayka, Project Engineer T. Chalky, QA Inspector
- Denotes those attending the exit interview.
Functional or Program Areas Inspected This inspection consisted of a review of Sargent and Lundy (S&L) specifica-tions and Napoleon Steel Corporation Incorporated (NSCI) procedures relative to post tensioning activities at the Braidwood site.
In process tendon buttonheading and stressing activities were observed. Storage facilities for tendons and appurtenant hardware were obs,erved. Quality records asso-ciated with post tensioning were reviewed. Field change requests, noncon-formance reports, and repair procedures on tendon installation were reviewed.
Investigation of failed bearing plate seat V157 on Unit I was accomplished.
Details of the functional and program areas inspected are documented in the following sections of this report.
1.
General The design of the Braidwood containment units utilizes the Inryco system BBRV 170 wire unbonded post tensioning system.
Individual tendons are capable of developing more than 2000 kips of ultimate force. The containment units are both the shallow dome, three buttress
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type. These vessels are cylinders, capped by elliptical domes with ring girders at the juncture of the wall and dome. The tendon systems
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for the walls and domes are indepeJdent, and installed separately.
The vertical wall tendons run from the tendon gallery below the base mat to the top of the ring girder. Dome tendons consist of three
. families oriented at 120* and anchored at opposite sides of the dome
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ring girder.
Circumferential tendons are at 240' system, with anchor-ages staggered at the three buttresses to provide equal numbers at each buttress. The design includes provisions for tendon detensioning for surveillance and testing.
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2.
Review of Sargent and Lundy Specifications and Napoleon Steel Procedures Sargent and Lundy (S&L) Specification L-2721 for containment post tensioning was examined in conjunction with the following NSCI Con-struction Procedures:
a.
Post Tensioning Material Re:eiving and Storage (7A).
b.
Tendon Installation (7B).
c.
Field buttonheading of Post Tensioning Tendons (7C).
d.
Stressing of Post Tensioning Tendons (7D).
e.
Field Greasing of Post Tensioning Tendons (7E).
The review was directed tow..J verifying thoroughness and compatibility of the specifications and procedures in the areas of procuring, storage, handling, corrosion protection, placement, buttonheading, stressing and greasing of the post tensioning system components.
No conflicts were noted between the specification and procedures. The procedures appear to provide sufficient control over the post tensioning construction and QA/QC program.
3.
Observation of Work Activities - Containment Post Tensioning a.
Storage Storage buildings for post tensioning components consist of a 60 by 100 ft. insulated building, a large portion of the station machine shop, and the receiving building. All buildings have concrete floors, and afford a relatively dry environment. The tendons are stored on dunnage, heavily coated with corrosion pro-tection grease, and covered with waterproof plastic sheeting arranged to provide protection while affording air circulation and drainage. Several tendons were visually checked for condensation, rust and/or corrosion, with none being evidenced. The storage areas meet requirements for Level D Storage, as described in ANSI N45.2.2.
b.
Tendon Buttonheading Tendon buttonheading was observed during replacement of a deficient shop anchorhead on tendon 14AB on September 10.
The deficient anchorhead was replaced with field head No. TAT 1, using button-head gun No. 9488. The individual buttonheads were checked by a QC inspector for verification of acceptable fillet radius and flashing width and to assure that split, slip, and eccentricity tolerances were not exceeded.
c.
Stressing (Unit 1)
Stressing was observed on tendon Nos. V-37, V-91, and V-145 with Jack Nos. 8751, 8791 and 8754, respectively, on September 16.
The tendons, which are all verticals in the Unit I containment,
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were stressed simultaneously, in accordance with the prescribed stressing order and sequence. The inspector verified that calibration of stressing equipment was current. A quality r.ontrol inspector was present to observe the stressing. All pertinant data was being recorded and checked. Tendon stressing cards were reviewed and discussed with the inspector.
4.
Review of Quality Records (Unit 1)
a.
Review of Records for Installation, Buttonheading, Stressing, and Greasing Records of dome tendons D1-4, D1-12, D1-18, D1-36, D2-16, D2-25, D2-40, D3-13, D3-15, and D3-38 were reviewed. The review verified that all pertinent information was inspected and recorded accord-ing to procedures. The records were complete and in order. Data recorded included installation particulars; buttonheading records with deficient or atypical heads delin '.ted on drawings with details of specific deficiencies; stressing ram pressures; shim thicknesses; total tendon clongations; and greasing records verifying the casings were appropriately filled with filler No.
2090P-4.
b.
Calibration of Measuring and Test Equipment The calibration / verification records of the following equipment were reviewed.
(1) Master Stressing Gauges N-298 and N-300.
(2) Field Stressing Gauges: N-296, N-297, N-301, N-304, N-305, N-306, N-307, N-308 and N-310.
(3) Thickness Gauges: F17, F18, F19, F20, N1, N2 and FG3.
(4) GO-NO-G0 Gauges:
BH-40, BH-65, BH-66 and BH-72.
(5) Grease Thermometers:
PK20 and PK22.
(6) Tanker Temperature Thermometers: T22, T23 and T24.
(7) Post Tensioning Ram / Jacks: 8751, 8752, 8754, 8791, 8795 and 9088.
The records indicated each item was properly calibrated in accordance with appropriately specified frequencies.
c.
Grease Shipmen'.s Records of grease rhipments no.'s 750515 (32,800 lb.) and 1123162 (12,600 lb.) were reviewed. The records contained appropriate documentation verifying that all physical and chemical require-ments were met, as specified in NSCI Procedure 7E.
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Personnel Certification / Qualification Records (1) Training records for 25 Post Tensioning production personnel were reviewed.
(2) The Region III inspector reviewed training records of four QA/QC inspectors. Three of these met Level II and one met Level III requirements in accordance with ANSI N45.2.6, and were certified accordingly.
5.
Tendon Pulling Problems (Unit 1)
While attempting to install tendons 28AC, 42AC, 17CB, (Circumferential)
V116, V117, (Vertical) and D2-24 (Dome), sheathing raveling occurred.
The raveling blocked the ducts, precluding insertion. Nonconformance Reports were generated, and were reviewed by the Region III inspector.
A procedure was prepared by Gust. K. Newberg Construction titled
" Removing Containment Building Concrete for Repair of Post Tensioning Ter$on Sheathing" (Procedure 41).
Repairs are being accomplished on all but dome tendon D2-24.
Gaining access to the plugged duct area would necessitate extensive concrete removal and replacement. CECO generated a Field Change Request (FCR NO. L-2301) September 9,1981. The FCR is currently under review by S&L.
6.
Bearing Plate Seat Failure (Unit 1)
The top bearing plate for vertical tendon V157 displaced as stressing was being accomplished on September 21.
Total jack pressure on the
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plate was approximately_700 kips when the displacement occurred. The licensee reported the matter in accordance with 10 CFR 50.55(e). The tendon was detensioned and concrete chipping operations were under way September 22 under direction of S&L engineers. Region III inspec-tors also observed the investigation.
Bearing plates for the 170 wire BBRV System are 20.5 inches square.
The plate edge adjacent to tendon V158 was approximately 2.5 inches below initial level. The four tendons (two on either side) of V157 were not stressed. Removal of concrete along the plate edge nearest the containment wall revealed a concrete void with a maximum depth of about 3 inches below the yielded plate bottom and extending under V158 plate. The bearing plates of V157 and V158 are approximately 1/4 inch apart.
Concrete pour records for the ring girder (pour folder IR-100-102)
were reviewed. The concrete was placed during prevailing warm weather conditions August 8, 1978.
It appears that good concrete workability was difficult.to maintain because of the elevated temperatures, with some relatively low sinmps recorded.
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l S & L engineers indicated repair would probably be accomplished by further void area chipping and clean out, then placing grout under the re-aligned plates.
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Exit Meeting
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The inspector met with licensee representatives (denoted under Persons Contacted) and conducted an exit meeting at the conclusion of the inspection.
The inspector summarized the purpor.e and findings of the inspection. The t
licensee acknowledged the findings reported herein.
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