ML061450101

GENE-0000-0051-3159, Rev 0, Similarity Analysis ERV Actuator 352B2632G001 Vs. Original Design, Quad Cities, Units 1 and 2

ML061450101
Person / Time
Site:	Quad Cities
Issue date:	03/10/2006
From:	Gibo E, Nieh C, Roit W General Electric Capital Corp
To:	Office of Nuclear Reactor Regulation
References
352B2632G001 DRF 0000-0049-8118, GENE-0000-0051-3159, Rev 0
Download: ML061450101 (12)

Text

GENE-0000-0051-3159 Rev. 0 DRF 0000-0049-8118 SIMILARITY ANALYSIS ERV ACTUATOR 352B2632G001 vs. Original Design Plant: Quad Cities Generating Station, Units 1 and 2 Utility: Exelon Generation Company, LLC Application: Dresser 6" 1525VX Electromatic Relief Valve Prepared by: W. J. Roit 03/09/2006 Verified by: C. T. Nieh 03/10/2006 Reviewed by: E. Gibo 03/10/2006 Verification with digital signatures filed in DRF 0000-0049-8118

GENE-0000-0051-3159 Rev. 0 DRF 0000-0049-8118 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 Exelon Generation Company, LLC and GE, Exelon Generation Company LLC P.O. 00000833 Release 00483 dated 01/27/2006, as amended to the date of transmittal of this document, and nothing contained in this document shall be construed as changing the contract. The use of this information by anyone other than Exelon Generation Company LLC, or for any purpose other than that for which it is intended is not authorized: and with respect to any unauthorized use, GE makes no representation or warranty, express or implied, 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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GENE-0000-0051-3159 Rev. 0 DRF 0000-0049-8118 Table of Contents

1. INT RO D U C TION : ............................................................................................................................................ 4

2. RE FEREN C E S: ................................................................................................................................................. 4

3. SUM M ARY :....................................................................................................................................................... 4

4. EV A LU A T ION : ................................................................................................................................................. 5 4.1 RETAINED PARTS NOT INCLUDED IN MODIFIED ACTUATOR .................................................................. 6 4.2 SOLENOID .................................................................................................................................................... 6 4.3 G UIDEPOST AND BRACE ASSEM BLY ............................................................................................................ 7 4.4 SPRINGS ...................................................................................................................................................... 8 4.5 RUBBER GASKET/PAD ................................................................................................................................. 8 4.6 COVER M ODIFICATION ................................................................................................................................ 9 4.7 RETAINED PARTS PROVIDED As PART OF NEW ACTUATOR...................................................................... 9 4.8 PARTS ELIMINATED WITH NEW ACTUATOR DESIGN .............................................................................. 9

5. ENVIRONMENTAL QUALIFICATION EVALUATION ...................................................................... 10

6. C ON C LU SION S: ............................................................................................................................................. 11 ATTACHMENT 1 PART BY PART COMPARISON ................................................................................... 11 3

GENE-0000-0051-3159 Rev. 0 DRF 0000-0049-8118

1. INTRODUCTION:

This document contains a similarity evaluation for the Dresser 1525VX Electromatic Relief Valve (ERV) actuator vs. the 352B2632G001 design. The actuator was redesigned for resistance to high plant vibrations. The modifications include non-buckling compression springs, bracing structures, tighter tolerances, wear resistant materials, and a vibration damping pad. The cover of the actuator is modified to accommodate the slightly greater height of the modification.

The GE 352B2632G001 design replaces the Dresser 3NC120 design. An item-by-item tabularized comparison is provided in Attachment 1 and described in further detail herein.

2.

REFERENCES:

2.1 352B2632, ERV Actuator Assembly and associated Parts List 2.2 Dresser Master Control Document 3NC 120, Sheet 6A Rev. 5, Sheet 6E Rev. 3, filed in GE DRF 0000-0049-8118.

2.3 PEP 42963, Project Engineer Program Test, Dresser Relief Valve Actuator, dated June 11, 1968.

2.4 Westec 6035-424, EQ of Dresser ERV Solenoid Actuator, March 5 1985 2.5 GE-NE-0000-0022-5936 Rev. 1, Similarity Analysis, DD233A3620P001 vs. CR9503-213CAT55 Solenoids, 1/8/04.

2.6 S&A Document 06Q4568-DR-001 Quad Cities ERV Actuator Vibration Testing Requirements, GE DRF 0000-0049-8118

3.

SUMMARY

Basic differences between the actuator being replaced, identified in Reference 2.2, and the replacement actuator, identified in Reference 2.1, are summarized in the following paragraphs, and detailed in Section 4.

The original ERV actuator solenoid was commercially identified as GE CR9503-213CAT55.

The current and new actuator both use the safety related GE DD233A3620P001. Similarity for the safety related design is established in the Reference 2.5 similarity analysis. The solenoid installed in the new actuator is strengthened for vibration resistance to incorporate gussets in the 4

GENE-0000-005 1-3159 Rev. 0 DRF 0000-0049-8118 lower angle brackets and hardened lever arm pivot pins and bushings. The improvements were made based on vibration testing, as identified in Reference 2.6.

The guidepost assembly was changed to incorporate wear resistant material, improve rigidity, and tighten tolerances. Guideposts were originally stainless steel posts, each welded to stainless steel brackets, later changed to nickel alloy X-750 rods welded to the same stainless steel brackets. The replacement actuator guideposts are cobalt alloy 6B rods threaded into a single stainless steel bracket. The threading the guideposts into a single bracket provides a stronger attachment without the distortion of welding, allowing precision placement. The replacement guidepost configuration includes a stainless steel brace assembly for increased rigidity and vibration resistance.

Spring guides that ride on the guideposts were originally bronze, later changed to nickel alloy X-750. The replacement actuator guides are manufactured from cobalt alloy 6B, for improved wear resistance.

The replacement actuator springs have a larger diameter to prevent contact with the guideposts.

To prevent buckling, two half-length springs are mounted in series with an intermediate cobalt alloy 6B guide. The new actuator spring configuration is of the same material and has the same effective spring rate and free length as the original single spring configuration.

A silicone rubber pad was added between the solenoid and baseplate to damp high frequency vibration. The originally tested actuator included a generic red rubber gasket at this location, later removed from the design. Silicone rubber has been evaluated for other silicone and silicone rubber components that exist in the solenoid assembly, effectively pre-qualifying it for this application.

Modification to the new actuator included reinforcement material that increased weight by approximately 6 lbs. As demonstrated by vibration testing, the increased weight does not impact the actuator assembly itself. Effect of increased weight on other components is beyond the scope of this analysis, being considered separately.

4. EVALUATION:

The actuator has evolved from improvements and replacement of obsolete parts since it was originally qualified for nuclear service. The original actuator, as it was originally qualified, is described in the Reference 2.3 and 2.4 qualification reports. The actuator configuration that is being replaced is as shown in the Reference 2.2 documents. The replacement actuator is as shown in the Reference 2.1 assembly drawing and parts list. contains a tabularized comparison of the Reference 2.2 actuator to be replaced and the Reference 2.1 replacement actuator on an equivalent part by part basis. Differences between the two configurations are further described and evaluated in detail in the following.

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GENE-0000-0051-3159 Rev. 0 DRF 0000-0049-8118 4.1 Retained Parts Not Included In Modified Actuator ERV parts modified or replaced by installation of the Reference 2.1 configuration are defined in the Power Actuator Group defined by 2heets 6A and 6E of the Reference 2.2 document. Some of the parts identified as part of the Power Actuator Group in sheets 6A and E are still required, but not assembled into the new actuator as defined in the Reference 2.1 document. These parts are the Bracket, Lever, and associated hardware, identified as parts 41, 42, 43, 44, 45, 46, 47, 58 and 59.

4.2 Solenoid The original solenoid, qualified per the Reference 2.3 and 2.4 documents, was commercially identified as GE CR9503-213CAT55. The reference 2.2 document identifies the safety related designation for the solenoid as DD23343620P001. The correct part number is DD233A3620P001. Qualification of the DD233A3620P001 solenoid is linked to the original Reference 2.3 and 2.4 qualification documents by the Reference 2.5 similarity analysis.

The GE DD233A3620P001 design solenoid is retained in the replacement design, further modified in the new actuator to include bottom angle bracket gussets and hardened pivot pins with associated bushings.

Gussets were found prudent for the lower angle brackets during vibration testing (Reference 2.6).

Cracking occurred in one of the lower angle brackets during lg sine dwells applied near the actuator natural frequency. The cause of cracking was considered to be due to concentration of stress at the angle bracket corners from the addition of the rubber pad, as described in Paragraph 4.4. The effectiveness of the gussets was demonstrated by successful testing after installation of gussets for longer periods at higher loads - - up to 4g sine dwells at the actuator natural frequency.

The cutout switch actuating lever pivot screws and mating holes in the solenoid frame demonstrated significant wear in service. During vibration testing, the pivot screws showed sufficient wear to prevent proper cutout switch operation (Reference 2.6). Both the original pivot screws and solenoid frame materials are low carbon steel. The solenoid assembly in the replacement actuator is modified to include Nitronic 60 pins and bushings to replace the low carbon steel wear couple. Nitronic 60 is the trade name for a special stainless steel alloy known to have excellent wear characteristics.

Changes to the solenoid are limited to structural improvements. The solenoid assembly's electrical characteristics (e.g. insulation class, resistances, inductances, and current vs. voltage characteristics) are not changed.

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GENE-0000-0051-3159 Rev. 0 DRF 0000-0049-8118 4.3 Guidepost and Brace Assembly The originally qualified actuators contained stainless steel guideposts welded to relatively thin stainless steel plates later changed to nickel alloy X-750 posts welded to the same stainless steel plates. The original guideposts are identified as parts 64 and 65 in the Reference 2.2 document.

The replacement actuator design utilizes cobalt alloy 6B guideposts threaded into a relatively thick, rigid stainless steel bracket, identified as parts 11 and 12 in Reference 2.1. The rigid single-bracket construction allows the guideposts to be precisely located a fixed distance from each other, with a high degree of parallelism. The threaded rod attachment avoids welding distortion. Furthermore, the /2 inch length of threads in the new design bracket provides a stronger joint configuration than the simple fillet weld of the original welded design.

The original guides that ran over the guideposts were bronze bushings brazed to stainless steel brackets, later changed to nickel alloy X-750 bushings welded to stainless steel brackets. The guide configuration being replaced is the spring bracket assembly, identified as part 71 in the Reference 2.2 document.

The Reference 2.1 replacement actuator utilizes cobalt alloy 6B spring guides mounted with a toleranced fit into a rigid bracket assembly. The parts are securely held in place by spring force, thereby avoiding distortion that is characteristic of a welded assembly. The upper guide and bracket are identified as parts 19 and 20 in the Reference 2.1 documents.

Cobalt alloy 6B was chosen for the guides and guideposts due to its exceptional wear resistance.

The alloy is commonly used in applications in the nuclear industry where a high degree of wear and corrosion resistance is necessary. Cobalt alloy 6B is commonly known by the trade name Stellite 6B. Cobalt alloy 6B is also corrosion resistant, which is important for the guides and guideposts, considering the need for smooth, clean sliding surfaces.

A stainless steel brace assembly is attached to the guideposts to further improve its rigidity and resistance to vibration. The brace assembly consists of parts 22, 23, and 24 as identified in Reference 2.1. The bracing is an addition to strengthen the new actuator and there are no equivalent parts in the Reference 2.2 assembly being replaced.

Replacement associated bolting is the same as in the original (zinc plated or plain steel screws, nuts and lockwashers), with screw lengths adjusted where necessary to accommodate the thicker bracket attachments. In some cases equivalent socket head screws are used. Although not necessary, the socket head screws are stronger than the original hex head screws.

The guideposts and bolting used in the guidepost bracket and brace assemblies are installed with application of a thread-lock compound (part 35 of Reference 2.1) for further resistance to vibration.

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GENE-0000-0051-3159 Rev. 0 DRF 0000-0049-8118 4.4 Springs To avoid rubbing contact with the guideposts and buckling, the replacement actuator design utilizes shorter, larger diameter springs. The original actuator springs were sized slightly larger than the guideposts and rode on the guideposts to prevent buckling. As described in the Reference 2.6 vibration report, spring contact with the guideposts during high vibration damaged both the springs and posts.

The larger diameter of the replacement springs avoids contact with the guideposts. To prevent buckling, two half-length springs are mounted in series with an intermediate cobalt alloy 6B guide. The new configuration (2 springs in series) was sized to provide same effective spring rate and free length as the original single spring configuration.

The springs are identified as part 70 for the actuator being replace per the Reference 2.2 document, and part 17 of the Reference 2.1 document for the replacement actuator. Both springs are high strength steel. The replacement actuator springs are specified for zinc plating to ensure corrosion resistance to prevent relaxation due to material thinning during high humidity conditions typically postulated for abnormal and DBE conditions.

4.5 Rubber Gasket/Pad The DBE tested actuator, tested per the original Reference 2.3 qualification test, included rubber gaskets between the solenoid and baseplate, and between the cover and baseplate. The gaskets were intended as environmental seals but did not provide positive sealing. They were considered ineffective and later removed from the design.

A rubber gasket between the solenoid and baseplate was re-added in the replacement actuator, as a rubber pad, identified as part 25 in Reference 2.1, to damp high frequency vibration. The replacement gasket is the same basic geometry as that in the originally tested actuator, except thicker (1/8" new vs. 1/16" original) to provide better damping characteristics. As noted previously, the actuator being replaced, as identified in Reference 2.2, does not have an equivalent rubber gasket.

The original gasket was manufactured from red rubber, which is generic for any synthetic rubber dyed red. The replacement rubber pad is made of high temperature silicone foam rubber.

A problem associated with rubber gaskets in bolted connections is that bolts can loosen with vibration as the gasket ages and exhibits compression set. To prevent fastener loosening with compression set of the gasket in the new actuator, potentially affected bolts are lockwired and have thread lock compound applied to their threads. The original split lockwashers are ineffective with the rubber gasket and are replaced with hardened flat washer equivalents in the new design. The original hex cap screws are replaced with drilled socket head cap screw equivalents for lockwiring purposes. The original bolting, identified as parts 61 and 62 in Reference 2.2, are replaced with screws, flat washers, and lockwire identified as parts 26, 27 and 28, respectively, in the Reference 2.1 document.

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GENE-0000-0051-3159 Rev. 0 DRF 0000-0049-8118 4.6 Cover Modification The added brace assembly, described in Paragraph 4.3, increased the overall height of the actuator, requiring modification of the cover. The original cover, identified as part 82 of the Reference 2.2 document, is a painted carbon steel welded sheetmetal structure.

The modified cover, identified as part 8 in Reference 2.1, is the original cover modified by cutting a rectangle out of the top of the existing cover and welding a carbon steel sheetmetal extension, which is then repainted. During vibration testing described in Reference 2.6, cover screw attachment holes enlarged, with cracks growing around the holes, requiring repairs. The repairs consisted of steel strips welded over the holes, with the holes redrilled. The replacement covers are modified to incorporate this improvement. Basic materials for the original and replacement covers remain the same (painted steel).

4.7 Retained Parts Provided As Part Of New Actuator Parts from the original actuator that are incorporated into the new design actuator without modification include the plunger head (roller), solenoid baseplate, microswitch, and microswitch cover, identified as parts 63, 57, 78, and 77 in the Reference 2.2 document for the actuator being replaced, and as parts 3, 4, 29 and 30 in Reference 2.1 for the replacement actuator.

Bolting retained from the original actuator may be the same or better material (e.g. brass screws may be replaced with plated steel equivalents).

4.8 Parts Eliminated With New Actuator Design Parts not used with the actuator modification include flat washers under the cover screw lockwashers, and finger screws with associated lock nut. The cover hole reinforcement described in 4.6 removes the need for flat washers to protect the previously thinwall cover. Flat washers under lockwashers reduces the locking effectiveness, therefore the flat washers were eliminated as a design improvement. The finger screws provided adjustment to the microswitches. The replacement actuator configuration allows microswitch levers to be adjusted directly for contact with the plunger bracket eliminating the need for the finger screws and associated nuts. The original actuator cover included a nameplate that is not included with the new actuator 9

GENE-0000-0051-3159 Rev. 0 DRF 0000-0049-8118

5. ENVIRONMENTAL QUALIFICATION EVALUATION With the exception of the silicone rubber gasket and thread lock compound, all changes to the actuator were to metallic parts. Metallic components are not susceptible to normal or DBE radiation and temperature conditions. Replacement parts requiring corrosion resistance are manufactured from corrosion resistant materials: plated steel, stainless steel, or cobalt alloy 6B and are therefore compatible with normal, abnormal, and DBE environments.

The modifications added to the weight of the actuator, which may affect dynamic analyses. The original and replacement actuators were weighed during the Reference 2.6 vibration test program. The replacement actuator was found to be 6 lbs heavier. The increased overall weight does not affect actuator function. Effect of the increased weight on other components is beyond the scope of this document.

The thread locking compound (Loctite 242) serves as a redundant anti-loosening method for bolting. Properly torqued metal-to-metal joints are resistant to loosening. Additionally, bolted connections in the ERV actuator either have safety related lockwashers or lockwire. The thread locking compound is therefore not considered essential to the actuator integrity or function.

The original actuator, as described in the Reference 2.3 and 2.4 reports, contained a solenoid gasket manufactured from "red" rubber. Red rubber can be any rubber that is dyed red, but is typically natural or a synthetic equivalent (polyisoprene). The replacement actuator gasket is made of high temperature silicone foam rubber. While silicone rubber is generally considered environmentally superior to natural or synthetic (polyisoprene) rubber, it was primarily chosen for this application due to its usage in the originally tested and current actuator designs. Silicone and silicone rubber components are used in several locations in the solenoid assembly (e.g.

varnish and lead wires). Silicone rubber is evaluated in the Reference 2.3, 2.4, and 2.5 qualification documents, effectively pre-qualifying it for use in the actuator, with radiation and thermal capability determined acceptable.

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GENE-0000-0051-3159 Rev. 0 DRF 0000-0049-8118

6. CONCLUSIONS:

The replacement actuators are equal to or better than the original and interim actuator designs, both functionally and for environmental qualification.

The replacement actuator is specifically designed to be more resistant to environmental vibration. The increased resistance was verified by vibration testing in comparison to the interim actuator design.

Thread locking compound (Loctite 242) is incorporated only where it acts as a redundant locking feature in bolted joints and is not considered essential for actuator integrity or function.

The only nonmetallic material change requiring consideration for environmental qualification is the addition of a 1/8" thick silicone rubber gasket/pad for the purpose of damping high frequency vibration. Silicone rubber is evaluated in qualification documents for parts in the actuator's solenoid assembly, effectively pre-qualifying it for use in the actuator.

All other changed parts are metallic. Metallic components are not susceptible to normal or DBE radiation and temperature conditions. Replacement parts requiring corrosion resistance are manufactured from corrosion resistant materials: stainless steels, cobalt alloy 6B.

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VERIFIED DRAFT GENE-0000-0051-3159 Rev. 0 ATTACHMENT 1. TABULARIZED ACTUATOR PART BY PART COMPARISON DRF 0000-0049-8118 PIN REP.21)bESCIPTIN MATERIAL I(E~l EC%~U A E~

NA SOLENOID VARIOUS 2 SOLENOID - SAME, STRUCTURALLY REINFORCED 4.2 42 LEVER CARBON STEEL NA NOT REPLACED SAME 4.1 S, 7 T -t I - -7 44 LEVER PIN ASSY STEEL, PLATED NA NOT REPLACED SAME 41 Ia  ! .I - I f ,¶ !-I 46 LOCKNUT STAINLESS STEEL NA NOT REPLACED SAME 41

..... . M I- 4.7 57 SOLENOID PLATE STEEL, PHOSPHATED 3 SAME PART SAME 59 LOCKWASHER STEEL PLATED NA NOT REPLACED SAME 41 0 -rtny f~ 6ic.riiI E *

• 7U1RCI3. OtNV /H /~fJ~flEI¶j'rnI ~ q 62 LOCKWASHER STEEL, PLATED 27 FLAT WASHER STEEL, PLATED OR PLAIN 45 64 SPRING GUIDE, RIGHT SS/INCONELX750 11,12 BRACKET & GUIDEPOST SS BRACKET, STELLITE 61 GUIDES 4.3 66 CAP SCREW STEEL, PLATED 13 CAPSCREW STEEL, PLATED 43

"-7 -r IVti.,lllC:IE..flCVY E-E -3WV'- 7 1 -7 Tr E IJ¶,rrrrIc, 1w 68 LOCKWASHER STEEL, PLATED 15 SAME PART SAME 43

' 71t. ii..Tp ff -- in) Z111 -fIV~

'ml**~

1 4 70 SPRING MUSIC WIRE 17 SPRING MUSIC WIRE, PLATED 44 72 CAP SCREW STAINLESS STEEL 21 CAP SCREW STEEL. PLATED 43 74 NUT STEEL 6 SAME PART SAME 4 3, 4.7 76 LOCKNUT STAINLESS STEEL NA REMOVED FROM DESIGN NA 48 78 ENCLOSURE ALUMINUM 29 SAME PART SAME 4.7 81 LOCIGKWASHER STEEL 32 SAME PART SAME 4,7 Oy!j.a I. .. ... J1.... ,_,.. . . .......................... . . .. .. . . .... _...

84 MACHINE SCREW STEEL 9 SOCKET CAP SCREW STEEL 4.7 L fICNIT- IV I * !1 I 89 WASHER STEEL NA REMOVED FROM DESIGN NA 48

// r I- I II- - I1 -r IIr III 91 SCREW. MACHINE BRASS 33 MACHINE SCREW BRASS OR STEEL, PLATED 4.7

,'.,I n Is I.

NA NO EQUIVALENT 23 SIDE BRACE STAINLESS STEEL 4.3

~~~~~~~~

I)wW oZý$Ifl O.III VtICI - ,lVII- Z ~~e k-;; -- C -. 1-13~MFUO NA NO EQUIVALENT 28 LOCKWIRE STAINLESS STEEL 4.5

• Pn Wr rIJ l tuL**wCIntUM

• l , 1u/-,

7 = .C* t** 'rFM

,i- -, 77 5 12