ML19316A223

Reactor Bldg Post-Tensioning Sys Initial Surveillance.

ML19316A223
Person / Time
Site:	Oconee
Issue date:	01/15/1973
From:	DUKE POWER CO.
To:
References
NUDOCS 7912030340
Download: ML19316A223 (15)

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i DUKE POWER COMPANY OCONEE NUCLEAR STATION i

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I UNIT 1 i REACTOR BUILDING POST-TENSIONING SYSTEM INITIAL SURVEILIANCE i.

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! January 15, 1973 1

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T."dLE OF CONTENTS Section P_aage

1.0 INTRODUCTION

1 2.0

SUMMARY

AND CONCLUSIONS 2 2.1

SUMMARY

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2.2 CONCLUSION

S 2 3.0 RESULTS 3 3.1 SHEATHING FILLER 3 3.2 END ANCHORAGE COMPONENTS 3 3.3 LIFT-OFF FORCES 3 3.4 WIRE SURVEILLANCE AND TESTING 4 3.5 RETENSIONING AND FILLER REPLACEMENT 4

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k LIST OF TABLES Table 1 SHEATHING FILLER INSPECTION 2 LABORATORY ANALYSIS OF SHEATHING FILLER 3 END ANCHORAGE COMPONENT INSPECTION 4 TENDON LIFT-OFF FORCES 5 AVERAGE TENDON LIFT-OFF FORCES 6 ULTIMATE STRENGTH OF TENDON SPECIMENS f

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LIST OF FIGURES Figure 1 TENDON SURVEILLANCE, FORCE-TIME PLOT i

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1. 0 INTRODUCTION The surveillance program for the Oconee Nuclear Station, Unit 1, reactor building post-tensioning system was defined, and is executed, in order to assure the continued quality of the system. The program consists of periodic inspections of nine (9) pre-selected tendons - three (3) hori-

ontal tendons, three (3) vertical tendons and three (3) dome tendons -

for symptoms of material deterioration or force reduction. The program assesses the condition and functional capability of the system and, therefore, verifies the adequacy of the system and provides an opportunity

, to take proper corrective action should adverse conditions be detected.

The requirements for the program are detailed in the Ocone 2 Nuclear Station, Unit 1, Tcchnical Specifications, Sections 4.4.2.1 and 4.4.2.2.

The initial tendon inspection, as specified therein, shall be within eighteen (18) months of the initial Reactor Building Structural Integrity Test. This test was conducted July 29 through August 4, 1971, and the specified surveillance was performed October 31 through December 6, 1972.

Surveillance was conducted in accordance with approved test procedure TP/1/B/0150/14, Reactor Building Tendon Surveillance Program, and the results of this initial inspection are reported herein.

2.0

SUMMARY

AND CONCLUSIONS 2.1

SUMMARY

No significant discoloration of the sheathing filler was observed. Labo-ratory analysis of sheathing filler samples revealed no detectable amounts of impurities to be present.

The end anchorage components were found to be in excellent condition with no sign of the development of adverse conditions such as cracking or ex-cessive cor.osion, or missing or deformed buttonheads.

The lift-off forces for all surveillance tendons were within the range of predicted values, considering the effects of concrete creep and shrinkage, steel relaxation and initial structural deformation.

The tendon wires were in excellent condition and no corrosion along the length of the wires was observed. It was determined that no wire breaks had occurred during the interval since the initial Reactor Building Structural Integrity Test.

Mechanical tests of specimens showed no significant changes in the ultimate strength of the wire as compared to results obtained during initial acceptance tests.

2.2 CONCLUSION

S Based on the tests and inspections described herein, it is concluded that the post-tensioning system for Oconee Nuclear Station, Unit 1, is in excellent condition, that the functional capability of the system has not diminished, and that the system shows no detectable evidence of the occurrence of any adverse deterioration.

3.0 RESULTS 3.1 SHEATHING FILLER The sheathing filler at the ends of the nine (9) surveillance tendons was visually examined. The filler coating on the end anchorage components, and the color and consistency of the filler, were found to be acceptable, with no evidence of water being present - see Table 1.

Samples of sheathing filler were obtained from each of three (3) tendons This filler was visually examined and no j from which a wire was removed.

signs of water nor any discoloration of the sheathing filler was evident. f Laboratory analysis of the filler samples revealed no detectable amounts of impurities to be present - see Table 2.

3.2 END ANCHORAGE COMPONENTS l

The results of the end anchorage component inspections are given La Table

3. Buttonheads were inspected for acceptable shape, general appearance, cracks and corrosion. No buttonhead defects or missing buttonheads were I observed. Stress washers, shims and bearing plates were visually inspected for cracking and corrosion. (Some millscale and minor surface corrosion were present on the edges and faces of shims and bearing plates. However, this condition existed at the time of installation and no deterioration has occurred in the interval since installation.)

3.3 LIFT-OFF FORCES Lift-off forces were obtained for each surveillance tendon. To assure i their validity, lift-off forces were measured three (3) times - see Table

4. These readings were converted to an average lift-off force per tendon

- see Table 5 - from which an average force per wire was d'etermined. The long-term trend of these wire forces is shown graphically in Figure 1.

Lift-off forces were within the range of predicted values, considering the effects of concrete creep and shrinkage, steel relaxation and initial structural deformation. .

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3.4 WIRE SURVEILLANCE AND TESTIHG One (1) surveillance tendon of each directional group was relaxed - 1D28, 13H9 and 23V14. One (1) wire was removed from tendons 1D28 and 23V14, and two (2) wires were removed from tendon 13H9. (Two (2) wires were removed from tendon 13H9 due to difficulty encountered in identifying the opposite ends of a particular wire.)

l The wires removed were visually checked for corrosion and ? itting and to determine their general condition. The tendon wires were found to contain minor surface scratches, resulting from insertion of the tendons into their sheaths at the time of installation, and heat treating discoloration.

The general condition of the wires was determined to be equivalent to their condition at time of initial installation.

Three (3) specimens were cut from each of the extracted wires for tensile testing. The samples were taken from the ends and the middle of each of the wires. The ultimate strength of each of the specimens was determined by tensile testing by the Prescon Corporation, Simpsonville, South Carolina. These tests are summarized in Table 6 and revealed no~signifi-cant changes in the ultimate strength of the wire as compared to results obtained during initial acceptance tests.

3.5 RETENSIONING AND FILLER REPLACEMENT Following wire removal the tendons were retensioned to approximately the same stress level indicated by the lift-off force data obtained during this surveillance. The sheathing filler which was removed during the surveillance process was replaced with new filler.

SilEATilING FILLER INSPECTION Filler Coating Acceptable Filler Color and nsistency Button Stress Bearing Tendon End lleads Washer Shims Plate Cap Acceptable ID28 Shop Yes Yes Yes Yes Yes Yes Field Yes Yes Yes Yes Yes Yes 2D28 Shop Yes Yes Yes Yes Yes Yes Field Yes Yes Yes Yes Yes Yes 3D28 Shop Yes Yes Yes Yes Yes Yes Field Yes Yes Yes Yes Yes Yes s

E. 1 3119 Shop Yes Yes Yes Yes Yes Yes n' Field Yes Yes Yes Yes Yes Yes e

51119 Shop Yes Yes Yes Yes Yes Yes Field Yes Yes Yes Yes Yes Yes 531I10 Shop Yes Yes Yes Yes Yes Yes Field Yes Yes Yes Yes Yes Yes 23V14 Shop Yes Yes Yes Yes Yes Yes Field Yes Yes Yes Yes Yes Yes 45V16 Shop Yes Yes Yes Yes Yes Yes Field * * * * *

• 61V16 Shop Yes Yes Yes Yes Yes Yes Field Yes Yes Yes Yes Yes Yes

• The field end of tendon 45V16 is a dead-end plate and inaccessible for this inspection.

LABORATORY ANALYSIS OF SHEATHING FILLER Water Soluble Water Soluble Water Soluble CHLORIDES NITRATES SULFIDES Tendon (Limit 1.0 ppm) (Limit 4.0 ppm) (Limit 1.0 ppm) 1D28 0.0 0.0 0.0 13H9 0.0 0.0 0.0 23V14 0.0 0.0 0.0 f

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Table 2

END ANC110 RAGE COMPONENT INSPECTION Buttonheads Stress Washer Shims Bearing Plate Tendon End Corrosior Cracks Shape Corrosior Cracks Corrosior Cracks Corrosion Cracks 1D28 Shop None None Good None None None None None None Field None None Good None None None None None None 2D28 Shop None None Good None None None None None None Field None None Good None None None None None None 3D28 Shop None None Good None None None None None None Field None None Good None None None None None None a None g 13119 Shop None None Good None None None None None y Field None None Good None None None None None None u

5 1119 Shop None None Good None None None None None None Field None None Good None None None None None None 5 3111 0 Shop None None Good None None None None None None Field None None Good None None None None None None 23V14 Shop None None Good None None None None None None Field None None Good None None None None None None 45V16 Shop None None Good None None None None None None Field * * * * * * * *

• 61V16 Shop None None Good None None None None None None Field None None Good None None None None None None

• The field end of tendon 45V16 is a dead-end plate and inaccessible for this inspection.

TENDON LIFT-OFF FORCES Lif t-Off Force (Psi)

Tendon End 1 2 3 1D28 Shop 5900 5950 5950 Field 6200 6100 6100 2D28 Shop 6200 6225 6250 Field 6100 6100 6150 3D28 Shop 6400 6350 6400 Field 5750 5800 5750 13H9 Shop 5600 5600 5600 Field 5700 5700 5700 SlH9 Shop 5950 5950 5950 Field 5550 5600 5550 53H10 Shop 6000 5950 6000 Field 5600 5600 5600 23V14 Shop 5700 5700 5750 Field 6000 6000 6000 45V16 Shop 5700 5700 5650 Field * *

• 61V16 Shop 5800 5800 5800 Field 5975 5950 5975

• The field end of tendon 45V16 is a dead-end plate and was inaccessible for taking lift-off readings.

Table 4

AVERAGE TENDON LIFT-OFF FORCES Tendon Average Force (Psi) 1D28 6033 2D28 6171 3D28 6075 13H9 5650 51H9 5758 53H10 5792 23V14 5858 1

1 45V16 5683 61V16 5883 l

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Table 5

ULTIMATE STRENGTH OF TENDON SPECLENS i

Break Tensile Specimen Force Diameter Area Strength Tendon Location (Lbs.) (In.) (In 2) (Psi) .

1D28 Shop End 12,400 0.2501 0.0491 252,545 l Center 12,350 0.2504 0.0492 251.016 Field End 12,300 0.2502 0.0492 250,000 13H9 (1) Shop End 12,450 0.2501 0.0491 253,564 Center 12,450 0.2503 0.0492 253,049 Field End 12,400 0.2502 0.0492 252,032 13H9 (2) Shop End 12,800 0.2501 0.0491 260,692 Center 12,850 0.2503 0.0492 261,179 Field End 12,850 0.2503 0.0492 261,179 23V14 Shop End 12,300 0.2503 0.0492 250,000 Center 12,350 0.2503 0.0492 251,016 Field End 12,400 0.2502 0.0492 252,032 i

Table 6

0 466 888 991 111 222 1 1 HH VVV DDD 3l3 351 123 1S5 246

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