ML071130384

GE-NE-0000-0066-0380-R1-NP, Pilgrim Nuclear Power Station, Torsion Arm Clamp Stress Evaluation Report.

ML071130384
Person / Time
Site:	Pilgrim
Issue date:	04/10/2007
From:	General Electric Co
To:	Office of Nuclear Reactor Regulation
References
eDRF 0000-0064-9390, eDRF Section 0000-0066-7000-R0 GE-NE-0000-0066-0380-R1-NP
Download: ML071130384 (15)

Text

w GE Energy,Nuclear General Electric Company 6705 Vallecitos Road Sunol. CA 94586 GE-N E-0000-0066-0380-Ri-N P eDRF Section 0000-0066-7000-RO eDRF 0000-0064-9390 Class I April 2007 Pilgrim Nuclear Power Station Torsion Arm Clamp Stress Evaluation Report

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GE-NE-0000-0066-0380-RI-NP GE Energy, Nuclear IMPORTANT NOTICE REGARDING THE CONTENTS OF THIS REPORT Please Read Carefully NON-PROPRIETARY INFORMATION NOTICE This is a non-proprietary version of the document GE-NE-0000-0066-0380-RI-P, which has the proprietary information removed. Portions of the document that have been removed are indicated by an open and closed double brackets as shown here (( )).

IMPORTANT NOTICE REGARDING CONTENTS OF THIS REPORT Please Read Carefully The only undertakings of the General Electric Company (GE) respecting information in this document are contained in the contract between the company receiving this document and GE.

Nothing contained in this document shall be construed as changing the applicable contract. The use of this information by anyone other than a customer authorized by GE to have this document, or for any purpose other than that for which it is intended, is not authorized. With respect to any unauthorized use, GE makes no representation or warranty, and assumes no liability as to the completeness, accuracy or usefulness of the information contained in this document, or that its use may not infringe privately owned rights.

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Revision Control Sheet Revision JDate Description Rev. 0 April 02, 2007 Incorporates Customer Comments Rev. 1 April 05, 2007 Added Proprietary Information identification

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1.0 INTRODUCTION AND BACKGROUND

((

)) This report documents the structural evaluation of the torsion arm clamp (Figure 1) to be installed during the upcoming outage at Pilgrim Nuclear Power Station. The safety evaluation of the torsion arm clamp contained in Reference 2 demonstrates that there is no safety concern in the current operating condition.

The replacement upper support and tie rod nut are also to be installed during the upcoming outage. The structural qualification evaluation of the replacement upper support and the tie rod nut is contained in Reference 3 report.

2.0 SCOPE The objective of the stress analysis presented in this report is to demonstrate that the torsion arm clamp as depicted in Reference 4 drawings satisfies the ASME Code limits (Reference 5) and the IGSCC criteria (Reference 3) of the (( )) component. The torsion arm clamp design features, qualification criteria, analysis approach, results, and conclusions are presented in the following sections.

3.0 HARDWARE DESIGN FEATURES

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GE-NE-0000-0066-0380-RI-NP GE Energy, Nuclear 4.0 HARDWARE MATERIALS The materials used in the torsion arm clamp and their properties are provided in Table 4-1.

Table 4-1. Materials Properties for Torsion Arm Clamp Components Properties(') @ 55O..F Component Material unless specified otherwise

= (Reference 5)

Sm 53,300 psi Sy 92.800 psi Locking Spring[i Su = 160.000 psi 6

E = 28.85x40 psi a = 7.50x10- 6 in/in/OF 70oF 5500F i"

' ""* "'* :"= "~

":........... ~...... ........

Sm. psi 33,300 29.450 Guide Bolt (( Sy. psi 55,000 38,050

] SU, psi 100,000 88.450 6 6 E,psi 28.3x10 25.55xi0 a, in/in/OF 8.24x10" 6 8.98xi0 6 Sm 29,450 psi Capture Cover [ = 38,050 psi Su = 88,450 psi E =25.55x106 psi

~Sm= Design Stress Intensity, Sy =Yield Strength, Su =Ultimate Stress, E= Young's Modulus, a = Thermal Coefficient.

5.0 STRUCTURAL ANALYSIS 5.1 Applicable Loads The torsion arm clamp consists of the guide bolt, locking spring and the capture cover.

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5.1.1 Guide Bolt Torques The guide bolt torque values used in the calculations are shown in Table 5-1. ((

)) (see Section 4.0).

Table 5-1. Guide Bolt Torques Torque at (( 1]

Service Level (ft-lbs) (ft-Ibs)

Service Levels A,B,C,and D (Normal, Upset, Emergency and ((I 1]

Faulted Conditions, respectively) 5.1.2 Locking Spring Ratcheting Cycles (for fatigue evaluation)

The ratcheting cycles for the locking spring ((

)) The use of (( 1]

cycles in this calculation is conservative.

5.2 Qualification Criteria 5.2.1 IGSCC Criterion For Locking Spring ((( )))

The maximum tensile principal stress (Pm + Pb + Q + F) in the sustained normal loading condition is compared to the IGSCC criterion of (( )) for (( )) components (Reference 3), where, Sy is the ASME Code minimum yield stress at the (( ))

temperature (See Table 4-1).

5.2.2 ASME Code Allowable Stress Limits The applicable service level A (Normal condition). B (Upset Condition), C (Emergency condition), D (Faulted condition), and ASME Code stress allowable limits are summarized in the Table 5-2 below.

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Table 5-2. ASME Code Allowable Stress Limits Service Level Stress Category Allowable Limit Components Other Than Threaded Fasteners (Ref. 5 NG-3220)

Pm Sm Service Levels Pm + Pb 1.5 Sm A& B Pm+ Pb+ Q 3.0Sm (Normal & Shear Stress 0.6 Sm Upset conditions) Bearing Stress 1.5 Sy (away from free edge) i Fatigue Usage 1.0 PM 1.5 Sm Service Level C Pm + Pb 2.25 Sm (Emergency Shear Stress 0.9 Sm condition)  : ~~~~1.

5 Sy . . . .. .

Bearing StressY 2.25 Sy (away from free edge)

Service Level D Pm M( 2.0 Sm (*)Conservatively (Faulted ..Pm + Pb .. original design condition) 3.0 Sm basis values used.

Shear Stress 1.2 Sm

i 2.0 Sy Bearing Stress 2 .0 .....

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Table 5-2. ASME Code Allowable Stress Limits (contd)

Service Level Stress Category Allowable Limit Threaded Structural Fasteners (Ref. 5, NG-3230)

Pm (Mechanical Loads) Sm Pm (Installation Torque) Min. (1.08 Sy, 0.8 Su) at installation temperature.

Pm + Qm Min. (0.9 Sy, 2/3 Su)

Service Levels Pm+ Pb + Qm + Qb Min. (1.2 Sy, 8/9 Su)

A&B Shear Stress 0.6 Sm (Normal &

Upset Threads (Primary) 0.6 Sm conditions) Shear Stress (Primary +

...... Secondary) .........

'Under 2.7 Sy bolthead Bearing Stress Shanks, I Fatigue Usage 1.0 Threads Same as for non-threaded Service Level C components.

(Emergency Pm, and (Pm+Pb) IfSu > 100 ksi, then same as condition) Level A/B limits for threaded components.

Shear Stress Same as for Level A/B limits for threaded components.

Pm Smaller of (2.4 S., 0.7 Su);

Service Level D IfSu>100 ksi, then 2Sm (Faulted Pm+Pb Smaller of (3.6Sm. 1.05Su);

condition) IfSu > 100 Ksi, then 3Sm Shear Stress Smaller of (0.42Su, 0.6 Sy)

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Table 5-3. IGSCC Allowable Limit (Reference 3)

Service Level Stress Category Allowable Limit

((

5.3 Analysis Methods The primary membrane, bending stresses, and shear stress were calculated for the above components os appropriate, and compared to the respective ASME Code allowable limits.

Where appropriate, fatigue, and IGSCC evaluations are also performed.

A brief description of the stress evaluation of each component is provided below. The component materials are shown in Table 4-1.

Locking Spring

((

)) The calculated primary membrane and bending stress is shown to be within the ASME code allowable limit. ((.

I]

((I I]

The ASME Code, IGSCC, and fatigue evaluation results are shown in Table 6-1 and Table 6-3, respectively.

Guide Bolt

)) The calculated stresses are shown to be within the ASME code allowable stress limits in Table 6-2.

Capture Covers Capture covers are evaluated for the guide bolt torque values specified in Table 5-1. The bearing stress due to the guide bolt head, and the bending stresses due to guide bolt preload acting on the cover plates are evaluated. The calculated stresses are shown to be within the ASME code allowable stress limits in Table 6-2.

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6.0 ANALYSES RESULTS 6.1.1 Results of IGSCC and ASME Code Stress Evaluation The ASME stress and IGSCC evaluation results of the locking spring, guide bolt, and the capture cover are shown in Table 6-1 through Table 6-3 as below.

Table 6-1. Stress Results - Locking Spring IGSCC ASME Code Stress Evaluation "I Description Pm+Pb 'Allowable Stress; Pm+Pb+Q+F SY Acceptance.

Criterion Stress Intensity limit Ratio Tensile Stressr(psi) (psi) (psi)

Intensity (psi) i

!Locking Spring It I(( ))

1[ 1))

1.5Sm = 79,950 (1) The ASME stresses in the Normal, Upset, Emergency, and Faulted conditions are the some as that due to installation.

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Table 6-2. Stress Results - Guide Bolt and Capture Cover ASME Code Stress Evaluation '

Description Stress (psi) Allowable (psi) Ratio

((i Min (0.9 Sy. 2/3'S.) @ 550oF = 34,245 11

((i Min (0.9Sy. 2/3 Sj)@ 70OF = 49,500 II Guide Bolt ((i 0.6Sy @ 550OF = 22.830 II 0.6Sy @ 70OF = 33,000 11

(( 2.7SY= 102,735 ))

))

Capture Cover

[I 1 *C -- u/rn 1 7L rr 1I (1) The ASME stresses in the Normal. Upset. Emergency. and Faulted conditions ore the same as that due to installation.

6.1.2 Results of Fatigue Evaluation Cumulative usage factor (CUF) was evaluated for the locking spring in accordance with the provisions of the Code, and using the cycles per Section 5.1.2. The number of rotcheting cycles is conservatively considered as (( )).

Table 6-3. Cumulative Usage Factor Component CUF Locking Spring 11 1 0--cL 10 o( 14

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7.0 CONCLUSION

Based on the stress evaluation of the torsion arm clamp provided above it is concluded that the torsion arm clamp meets the IGSCC criterion and ASME Code requirements for all operating conditions. Therefore, the torsion arm clamp is structurally qualified for installation at Pilgrim Nuclear Power Station.

8.0 REFERENCES

1. GENE-0000-0064-9392-R2-P, "Pilgrim Unit 1 IGSCC Assessment of Shroud Repair X-750 Components Other Than The Replacement Upper Support Assembly and Tie Rod Nut".

March 2007.

2. Letter No. JXG9E-014, March 22, From Mark Serpa, Project Manager, GE Energy, Nuclear to Fred Wozniak, Project manager, Pilgrim Upper Support Replacement, "Modification to Correct Consequences of Overstressed Tie Rod Upper Support Torsion Arm Bolt.

3. GE-NE-OO00-0061-6306-R4-P, "Pilgrim Nuclear Power Station Shroud Repair Replacement Upper Support Assembly - Stress Analysis Report", March 2007.

4. Torsion Arm Clamp Drawings Capture Cover A Capture Cover A Capture Cover B Locking Spring Locking Spring Guide Bolt

5. ASME Boiler and Pressure Vessel Code,Section III, Division I, Nuclear Power Plant Components, a) Subsection NG, Core Support Structure, 2001 Edition through and Including the 2003 Addenda.

b) Code Case N-60-5, Material for Core Support Structures,Section III, Division 1.

6. Stress Concentration Factors: Roark's Formulas For Stress and Strain, 6th Edition, Table 37-23, p.741.

7. Stress Concentration Factors: Peterson's Chart 5.21 (b = d, CHARTS pp.432)

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1l Figure 1. Torsion Arm Clamp "e12 of 14

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Figure 2. Torsion Arm Bolt Layout

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It 11 Figure 3. Torsion Arm to Upper Spring Slot and Tab Features Or,, P14 o14