ML17258B008

June 1981 Tendon Surveillance Program.

ML17258B008
Person / Time
Site:	Ginna
Issue date:	04/27/1981
From:	ROCHESTER GAS & ELECTRIC CORP.
To:
Shared Package
ML17258B007	List: ML17258B006 ML17258B008
References
PROC-810630, NUDOCS 8105050455
Download: ML17258B008 (17)

Text

June 1981 Tendon Surveillance Program Robert E. Ginna Nuclear Power Station April 27, 1981

1 JUNE 1981 SURVEILLANCE PROGRAM

1.0 INTRODUCTION

The June 1981 tendon surveillance program is presented in detail.

The program includes the liftoff of fourteen (14) tendons including the four (4) tendons with load cells. The data collection system required will not only confirm the liftoff data, but it will also obtain data needed to continue the investigation into the larger than predicted tendon losses. The inspection and selection process discussed in the Proposed Revision 3 to USNRC Regulatory Guide 1.35 are followed. The measured force for each tendon will be evaluated with respect to its predicted lower limit force discussed in this guide. These predicted lower limit forces are obtained using the loss calculation methodology described in the Proposed USNRC Regulatory Guide 1.35 Position l.

2.0 OB JECTIVES, The June, 1981 surveillance program is required to verify that the tendon forces are within the technical specifications and to provide further information as to why tendons have experienced prestress losses in excess of their predicted values. This surveillance program as outlined herein has four objectives:

1 ~ To measure lift-offforces in selected tendons.

2. To compare lift-off forces with those predicted, using either the existing relaxation data and/or retensioned wire data from the testing currently underway at Lehigh University.

3. To compare the two force measuring systems:

a. Strain gaged stressing rod.

1 W

b. Pressure gauge and effective ram area.

4. To test the 6% overstress effect.

The following surveillance program is intended for use only in June '1981. It is expected that the detail data gathering proposed will not be necessary on subsequent surveillances.

3.0 TENDON SELECTION 3.1 The tendon selection process will:

1. Verify that tendon force losses have stabilized.

.2. Survey enough tendons to extend present data base.

3. Include all four tendons with load cells.

4. Include tendons retensioned at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> after initial stressing.

5. Include tendons from each tendon mark category.

3.2 Table 1 contains the complete list of selected tendons.

3 3

~ To verify that the tendon force loss has stabilized,-tendons 62 and 76 are selected because they experienced large losses during the first eleven (ll) years. Tendon 51 is selected as an average loss tendon and 155 as a minimal loss tendon.

3.4 To extend the data base, tendons 17 and 84 are selected because they each have four (4) recorded data points.

3.5 Load cells are present under tendons 13, 53, 93, and 133, therefore, these are selected for surveillance. Tendons 133 and 13 will be used to evaluate the 6/ overstress effect.

k I'

3.6 To include tendons retensioned at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />, four are selected; two surveyed previously (36 and 111) and two not surveyed (33 and 116).

4.0 TEST PROCEDURE FOR LIFT-OFF 4.1 Initial Conditions

1. Plant may be in any phase of operation.

2. Pressure gauge has been calibrated.

3. Hydraulic ram area has been calibrated.

4. Hydraulic pump and ram are functional and ready for operation.

5. Load cells and stressing rod have been calibrated.

6. All tendons to be stressed have been inspected for broken wires and corrosion.

7. Containment structure has been inspected for cracks, spalling, etc.

4.2 Precautions

1. Observe all RGB safety rules and regulations.

2. Do not exceed 6560 psi gauge pressure for jack and tendons.

3. Whenever hydraulic pump is operating, the reservoir vent valve must be open.

4. Do not extend ram more than 8 inches.

4.3 General Instructions

1. Fill in line 1-4 on the data sheet (See Appendix I) and record comments from the visual inspection on line 5.

2. Move assembled hydraulic jack to position for coupling to the anchor head and place the pump in a convenient location for operation.

a. Carefully thread stressing adaptor onto tendon anchor head.

Note: Leave a minimum of one thread and maximum of three threads on tendon anchor exposed below the lower edge of the stressing adaptor.

b. Place jack assembly, on tendon base plate.

c. Center jack chair carefully over tendon head and thread stressing rod into stressing adaptor.

d. Center compression shims and tighten jack rod nut at top (ram) end of jack being careful not to damage strain gaged area and the electrical connector on top of the, jack rod.

3. Make the appropriate strain gage connections and check for malfunctions.

4. Before attaching hoses to jack for the first tendon, check pump and hoses by performing the following:

a. Set valves to pump position.

b. Start pump at the same time depress the ball valve.

c. Pump slowly to fill hose with oil until it comes out of the hose free of bubbles.

d. Release ball valve and start pumping again. Continue pumping; hose will become stiff; gauge pressure will rise rapidly and then hold constant.

5. Reduce pressure and connect hoses to jack.

6. Record all initial readings in the appropriate columns on the data sheet.

7. Start pump and increase pressure to 2,000 psi.

a. Record stressing rod reading in column 3a on data sheet.

b. Record load'ell reading in column 4a on the data sheet if tendon has load cell.

c. Record ram position in inches in column 5 on data sheet.

d. Calculate and record force values for the stressing rod, pressure gauge and load cell.

8. Increase pressure up to 4,000 psi and hold.

a. Inspect for leakage of hydraulic fluid and note if leakage is excessive.

b. Record stressing rod and load cell (if tendon has load cell) -readings in the appropriate columns on the data sheet.

c. Calculate and record force for the stressing rod, pressure gauge and load cell.

9. Increase pressure until a 0.035 (1/32) inch thick feeler shim can be inserted into the shim stack at two equally spaced positions around the shim stack.

10. Reduce ram pressure 1000 psi or until the feeler shims cannot be removed. Increase pressure until both feeler shims can be removed. Note in the comment section if there is a large difference in the load at which each feeler shim can be removed.

This is defined as liftoff.

a. Record the pressure gauge reading on the data sheet in column 2a.

b. Record the stressing rod reading on the data sheet in column 3a.

c. Record the load cell reading for load cell tendons in column 4a.

d. Record the ram position in column 5 of the data sheet.

e. Calculate and record force values.

11. Stress tendons 13 and 133 an additional 6% over recorded liftoffpressure.

a. Record computed 6/ overstress pressure on data sheet in column 2a.

b. Increase pressure to computed 6/ over stressing pressure and record stressing rod reading, load cell reading and ram position on the data sheet.

c. Place two .035 (1/32) inch thick feeler shims in the shim pack and reduce ram pressure to approximately 2900 psi.

l'

d. Slowly increase pressure until the feeler shims can be withdrawn from shim stack. This is defined as liftoff.

Record load cell, pressure gauge, strain gage and ram position on data sheet.

e. Calculate and record force values on data sheet.

12. .Decrease pressure to approximately 4,000 psi.

a. Record stressing rod reading, load cell and ram position on the data sheet.

b. Calculate and record force values on data sheet.

13. Decrease pressure to approximately 2,000 psi.

a. Record stressing rod reading, load'cell reading and ram position on the data sheet.

b. Calculate and record force values on the data sheet.

14. Decrease pressure until all load is removed from jack rod.

a. Record stressing rod reading, load cell reading and ram position on the data sheet.

15. Remove jack assembly from tendon.

a. Disconnect strain gage equipment.

b. Unthread stressing rod from coupler.

c. Remove jack chair and stressing rod assembly.

d. Remove adapter from tendon head.

16. Record any comments concerning liftoff on the data sheet.

17. Move to next tendon.

5.0 DATA COLLECTION PROCEDURES 5.1 Test Data - Record all data as required in 4.0, Test Procedure for Liftoff 5.2 Data sheet - The proposed data sheet is presented in Appendix I.

5.3 Strip chart recordings of force from load cell tendons will begin when the jack assembly is moved from that tendon and continue for 500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br />.

6.0 TENDON SURVEILLANCE SEQUENCE The schedule is presented in Table 2.

7.0 ACCEPTANCE CRITERIA The measured liftoff.forces will be evaluated in accordance with the present "Ginna Technical Specifications."

Table 1 TENDON SELECTION Tendon Tendon Number Mark Comments 13 A Load cell 17 C Maximum recorded data

'33 GS Retensioned at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> 36 HT Retensioned at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> 51 A Average ll year loss 53 A Ioad cell 62 A Large ll year loss 76 B Large 11 year loss 84 A Maximum recorded data 93 A Ioad 'cell 111 A2 Retensioned at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> 116 ER Retensioned at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> 133 A Load cell 155 A Small 11 year loss

10 Table 2 TENDON SURVEILLANCE SE(}UENCE Sequence Tendon Number Number S ecial Instructions 13 I,oad cell and 6/ overstressing 17 33 36 51 53 Load cell 62 76 9 84 10 93 Load cell ll 111 12 116 13 133 Ioad cell and 6/ overstressing.

14 155

Appendix I Data Sheet - June 1981 Tendon Surveillance

12 DATA SHEET 1 - JUNE, 1981 TENDONSURVEILLANCE RG&E GINNA NUCLEAR POWER STATION ROCHESTER GAS AND ELECTRIC CORPORATION

1) Date Tendon No. Shim Stack Thickness

2) Hydraulic Jack No. Ram Area"=

3) Hydraulic Pump No. Pressure Gauge No.

4) Load Cell Factor-- Stressing Rod Gage Factor~'~

5) Tendon Inspection Comments 1 2 3 4 5 6 Condition Pressure Gau e Stressin Rod I.oad Cell Ram Position Comments a (b a b b Pressure Force" Strain Force-- Strain Force""" inches

( si) (lbs) (m in/in) -(lbs) (m in/in) (lbs)

Initial Increasing 2000 Increading 4000 Liftoff Liftoff+ 6g (Tendons 13 & 133)

Liftoff Decreasing 4000 Decreasing 2000 Decreasin 0

13 DATA SHEET 1 (Cont'd)

Notes: (-) Ram area to be used to calculate ram force in column 2b: Force = Ram Area x Pressure Load Cell Factor to be used to calculate force in column 4b: Force = Load Cell Factor x (Strain 'Reading - Initial Strain Reading)

Stressing Rod Gage Factor to be used to calculate force in rod in column 3b: Force =

Stressing Rod Gage Factor x (Strain - Initial Strain Reading)