ML14079A532

From kanterella
Jump to navigation Jump to search
ULNRC-06092 Enclosures Part 2 - 10 CFR 50.55a Request Number I3R-16 Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(ii) --Hardship or Unusual Difficulty Without Compensating Increase in Level of Quality or Safety--
ML14079A532
Person / Time
Site: Callaway Ameren icon.png
Issue date: 03/20/2014
From:
Ameren Missouri, STARS Alliance
To:
Office of Nuclear Reactor Regulation
References
ULNRC-06092
Download: ML14079A532 (16)
v • d • e


Text

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002 DISPOSITION TYPE: D Design change 0 Configuration change SAFETY r:l SR CLASSIFICATION: ~ Safety Related D 55 Special Scope D NSR Non-Safety Related Special Scope Category:

D Fire Protection D Quality Group D (augmented) systems D Non-Category I Seismic and Seismic 11/1 D Station Blackout ATWS Mitigation System Actuation Circuitry D (AMSAC) D Non Special Scope Category:

D Security Systems I Plan D Contains Safe Guards Information CORRECTIVE ACTION DISPOSITION CATEGORY:

r:1

~ Repair D Rework D Use as is D Other D N/A Prepared by Bryan Sprock Date 1-21-14 Reviewed by Nikki Green Date Qualification Required for change package review Approved Bruce Huhmann Date DOCUMENT CONTROL RELEASE: DATE:

1 of 16 STARS- ENG -5001-8.1 09/04/1 2 Page 23

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002

1. ENGINEERING CHANGE

SUMMARY

ADCN CAR 201307879 documented a pinhole leak on the plant south manway of EEG01A. This modification will design and install a leak repair device that can be credited in Operability space.

The pinhole leak is located on a ASME Section III Class III 24 inch T-bolt closure designed by Tube Turns and given serial number 8616. The hub and head of the closure is SA516 Grade 70 with a nominal thickness of 0.5 inches and a 0.125 inch corrosion allowance.

The leak repair device will consist of square stock welded between existing hub nut mounts of aT-bolt closure. The square stock will be drilled and tapped to accept a threaded rod or bolt that will push a gasketed steel block over the pinhole leak. All materials will be procured safety-related and the resulting repair credited for maintaining pressure boundary at the pinhole leak location. The gasket will measure 1" x 1" such that it is engaging portions of the closure hub beyond the pinhole leak.

Upon restoration of the degraded condition to a Code-compliant condition, this Modification will be made non-functional and at least partially removed. The hub nut mount to swing nut weld, standoffs and crossmember may remain in place.

2 of 16 STARS- ENG -5001-8.1 09/0411 2 Page 24

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair MP 14-0002 Mod No./Rev FRONT VIEW SIDE VIEW

) I 1 Orossmember I I Existing Structure Existing Structure OBJECTIVE Purpose Reduce the leakage that must be assumed in assessing Operability of EEG01A with a pinhole leak on the plant south manway.

Scope The scope of this modification is the pinhole leak identified in ADCN CAR 201307879 on EEG01A.

Initiating Document RFR CAR 201309376 and ADCN CAR 201307879.

Background

3 of 16 STARS - EN G - 5001- 8 .1 09/04/ 12 Page 25

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002 ADCN CAR 201307879 documented a pinhole leak on the plant south manway of EEGOlA. In accordance with the operability guidance of RIS 2005-20 Rev.l, leakage from an ASME Code Class 1, 2, or 3 component must be volumetrically characterized in assessing the operability of the component. An area 112" in diameter cannot be volumetrically examined and was therefore assumed to fail when assessing the postulated leakage due to the through wall leak. This postulated leakage rate has significantly reduced the volume margin in the Ultimate Heat Sink (UHS).

This modification will design and implement a temporary leak mitigation device that can be credited in Operability space. This is a "repair" as defined in ANSI/ANS-3.2-1994 section 2.2 which defines a repair as: "The process of restoring a non-conforming characteristic to a condition such that the capability of an item to function reliably and safely is unimpaired, even though the item still does not conform to the original requirement".

This modification is a Compensatory Measure as defined in RIS 2005-20 Rev. 1 section 7.3 which in part defines a Compensatory Measure as an action that:

"Maintain(s) or enhance(s) an operable but degraded or nonconforming SSC's capability to perform its specified safety function, or as the next logical step in support of corrective maintenance or to compensate for the degraded or nonconforming condition."

RIS 2005-20 Rev. 1 section C.ll states that: "The NRC expects that components be restored to ASME Code or Construction code acceptance standards by the end of the next refueling outage." PerRIS 2005-20 Rev. 1 section C.12: " .. all such flaws in these components must be repaired in accordance with ASME Code requirements, or relief from ASME Code requirements must be requested of and approval obtained from the NRC."

While the structural integrity of the pinhole leak is determined herein to meet approved Code case N-705 (attached) with or without the repair device in place, the repair implemented via this modification does not meet Construction Code, nor does it comply with an NRC endorsed Code case. Additionally Code case N-705 may only be applied for a maximum of 26 months since discovery of the condition, which was October 14th of 2013 in this case.

2. ENGINEERING DISPOSITION System Description and Configuration 4 of 16 STARS- ENG -5001-8.1 09/04112 Page 26

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002 The Component Cooling Water (CCW) system transfers heat from numerous safety-related sources to the ESW system. EEGOlA is the "A" train Component Cooling Water Heat Exchanger. CCW is circulated through the shell side of EEGOlA and the cooler ESW is circulated through the tube side of the heat exchanger. The pinhole leakage is on the tube side of the heat exchanger thus any leakage results in a loss from the Essential Service Water (ESW) system and ultimately volume loss from the UHS .

Alternative Solutions Considered Performing a temporary or permanent Code repair was considered. Engineering has been directed to prepare a temporary non-code repair option.

5 of 16 STARS- ENG -5001-8.1 09/04112 Page 27

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002

3. DESIGN EVALUATION Essential Design Inputs (Ref: APA-ZZ-00600)

The following table lists the design inputs identified in APA-ZZ-00600 that must be reviewed and evaluated for applicability to the proposed change.

Item Design Input Potentially No. Impacted?

1. Basic functions of each structure, system and component. (discussion required)
2. Performance requirements such as capacity, rating and system output. (discussion required)
3. Codes, standards and regulatory requirements including the applicable issue (discussion and/or addenda. required)
4. Design and operating conditions such as pressure, temperature, fluid (discussion chemistry, and voltaqe; includinq normal and abnormal conditions. required)
5. Loads such as seismic, wind, thermal, dynamic, pressure, thermal expansion, y thermal transients, anchor and support movement, and reactions of supportinq luqs rinqs saddles or other types of supports.
6. Environmental conditions anticipated during storage, construction and N operation (including postulated accident conditions) such as pressure, temperature, humidity, corrosiveness, site elevation, wind direction, nuclear radiation, electromagnetic radiation and duration of exposure.
7. Interface requirements including definition of the functional and physical N interfaces of structures, systems and components such as stiffness, electrical requirements (voltage, phase, conduit size), piping connections (size, schedule) , etc., physical interfaces involving structures, systems and components interface loads.
8. Material requirements, including such items as compatibility, electrical (discussion insulation properties protective coatinq and corrosion resistance. required)
9. Mechanical requirements such as vibration stress shock and reaction forces. y
10. Structural requirements covering such items as equipment foundations and N pipe supports.
11. Hydraulic requirements such as pump net positive suction head (NPSH), N allowable pressure drop and allowable fluid velocity.

12 . Chemistry requirements such as provisions for sampling and limitations on N water chemistry.

13. Electrical requirements such as source of power, voltage, raceway N requirements, electrical insulation and motor requirements.
14. Layout and arrangement requirements including equipment access within the N plant.
15. Operational requirements under various conditions, such as plant startup, N normal plant operation, plant shutdown, plant emergency operation, special or infrequent operation and system abnormal or emerqency operation.
16. I&C requirements including indicating instruments, controls and alarms N required for operation, testing and maintenance. Other requirements such as the type of instrument, installed spares, range of measurement, interlocks, remote local control and location of indication should also be included .

6 of 16 STARS- ENG - 5001- 8.1 09/0411 2 Page 28

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002 Item Design Input Potentially No. Impacted?

17. Access and administrative control requirements for plant security and N safeguards information.
18. Redundancy, diversity and separation requirements of SSCs. N
19. Failure effects requirements of SSCs, including a definition of the events and y accidents which they must be design to withstand.
20. Test requirements including in-plant tests and the conditions under which they (discussion will be performed. (Also discuss acceptance criteria .) required)
21. Accessibility, maintenance, repair & inservice inspection requirements for the y plant including the conditions under which these will be performed.
22. Personnel requirements and limitations including the qualification and number N of personnel available for plant operation, maintenance, testing and inspection and permissible personnel radiation exposures for specified areas and conditions.
23. Transportability requirements such as size, shipping weight, limitations, and N Interstate Commerce Commission regulations.
24. Fire Protection or resistance reg uirements. N
25. Handling, storage, and shipping Requirements.
26. Other requirements to prevent undue risk to the health and safety of the N public.
27. Materials, Processes, Parts and Equipment Suitable for the Application . N Discuss references to any design procurement or fabrication specification.
28. Safety requirements for preventing personnel injury, including such items as N radiation hazards, volatile chemicals, restricting the use of dangerous materials, escape provisions from enclosures, grounding of electrical systems and including OSHA requirements.
29. ALARA requirements. (Refer to ZZ-003) N
30. Special Installation Requirements (FME etc.) N
31. Special Processes including welding and painting . y
32. Overpressure protection . N
33. Human factors. N
34. Reliability requirements. N
35. Requirements for criticality control and accountability of nuclear materials. N
36. EPRI Report NP-5479 should be consulted for all modifications involving N existing or new check valves.
37. Basis for selection of setpoints and setpoint margins. For safety related N instruments, address the methodology for accounting for instrument uncertainties.
38. Approval to cut reinforcing steel obtained from Civil Engineering Design prior N to designating a required opening as a designed penetration.
39. All non-grouted penetrations through safety related fire barriers given N penetration numbers and updated on the M-2X and M-2Y drawings. All penetrations closures around field routed items though seismic block walls installed utilizing flexible materials per Note 4 of M-2Y001.
40. Any attachment to a large motor or generator has been analyzed. N 7 of 16 STARS- ENG - 5001- 8.1 09/0411 2 Page 29

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002 Item Design Input Potentially No. Impacted?

41. All designs which affect Motor Operated Valves (MOV) covered in Generic N Letter 89-10 should have as a minimum the following design inputs reviewed:
  • Configuration changes which may affect DP determinations
  • Electrical changes which may affect degraded voltage, running current or other electrical or actuator characteristics of the MOV
  • Actuator chanqes in confiquration which may affect valve loadinq
42. The above should be done to ensure that original assumptions and design N bases for 89-10 valves have not been affected.
43. The ICES Database maintained by INPO should be reviewed for applicable (discussion Industry Operating Experience. required)
44. All Engineering Design Changes that may introduce a new failure mode or may affect a design function MUST include documentation of a Failure Modes and Effects Analysis. The level of effort and discussion should be commensurate with the potential impact of the change.

For additional guidance on preparation of FMEAs, Refer To:

  • ZZ-006, Engineering Changes, Failure Modes and Effects Analysis Guidelines
  • INPO 92-014 Good Practice for Preventive Maintenance Program (discussion Enhancement required for
  • IEEE Standard 352- "IEEE Guide for General Principles of Reliability design Analysis of Nuclear Power Generating Station Safety Systems" changes)
  • EDP ZZ 04056, Development and Configuration Management of Digital Plant Systems
45. Consider if the design change introduces or increases the potential for gas N accumulation as described in the NRC Generic Letter (GL) 2008-01: "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" and provide the necessary justification.
46. Ensure compatibility of all petroleum-based products (i.e., hydraulic oil, N grease, lubricants, etc.) with any sse that will contain or interface with them .

Review such items as gasket integrity, suitability of the product for the environment they will operate, material interactions, lubrication frequency, etc.

47 . EVALUATE impact of the design change on the reactor vessel embrittlement N requirements, i.e., charpy upper- shelf energy and pressurized thermal shock screening criteria, and the P-T limit curves, including the effect of lower cold leo temperature or hioher fluence.

Essential Design Input Discussion

1. Basic Function EEGOlA is a shell and tube heat exchanger that transfers heat from numerous safety and non-safety related loads to the Essential service water and ultimately the Ultimate Heat Sink. Component cooling water is circulated through the shell side of EEGOlA and the cooling medium essential service water is circulated through the tube side of EEGOlA.

8 of 16 STARS- ENG - 5001- 8.1 09/0411 2 Page 30

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002

2. Performance and other requirements The temporary repair must provide a credited pressure boundary for EEG01A in the vicinity of the pinhole leak. In order to be credited, a seal must be generated outside the area which could not be volumetrically characterized. The repair must allow for continued monitoring of the degraded condition . When the repair device is partially removed for UT, the reduction in postulated leakage due to MP 14-0002 obviously cannot be credited .

The repair device was evaluated in regards to Code case N-705 and it was determined that gasket stress should be limited to ensure margin remains in the N705 evaluation. The N705 analys is attached to this MP limited gasket stress to 1300 psi over the same 1" by 1" square gasket area. Therefore, the force applied at the pinhole leak is limited to 1300 pounds force. Gaskets performing best in this regime will likely be rubber material. EPRI Technical Report 1000922 "Assembling Bolted Connections Using Sheet Gaskets" concluded that assembly stresses for rubber gasket should be in the 400-900 psi range with 750 being a reasonable target. Garlock's current guidance for homogenous rubber is a minimum of 600 psi stress and a maximum of 900 psi for Shore A durometer of less than 70, and a maximum of 1200 psi for durometer 70 or greater. EG-57 determined 224 in - lbs was necessary to generate 2800 psi stress. By ratioing 600, 900 and 1200 pounds to EG- 57's 2800 pounds, the torque to generate 600 psi is 48 in-lbs, to generate 900 psi is 72 in-lbs, and for 1200 psi is 96 in-lbs.

3. Codes and Standards EEG01A is an ASME Section III Class III vessel. This temporary repair is a non-Code repair thus Code requirements are not incorporated into this design.

Code case N-705 does not disallow the use of non-Code repairs to reduce leakage.

4 . Design and Operating Conditions The leak being stopped is on the tube side of EEG01A. The des ign pressure and temperature are 200 psi and 200°F respectively per M-072-00022 Rev. 001.

All materials selected herein are acceptable for these service conditions.

EEG01A is located in a mild environment thus the design temperature and pressure are adequate parameters for the design of the temporary repair device.

9 of 16 ST ARS - ENG - 5001- 8.1 09/04112 Page 31

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002

5. Loads and React1ons Calculation EG-57 Rev. 000 has calculated very conservative bounding loads and reactions based upon a 4200 pound point load versus the N705 limiting load of 1300 pounds. All materials selected have tensile strength in excess of the calculated loads. Additional load on existing structures was also calculated and found acceptable in EG-57 Rev. 000.

The application of up to 1300 pounds at the pinhole leak location will not create any significant deflection. The closure hub has a bevel on the end to act as a seating surface for the closure 0-ring. The direction of the bevel is such that any deflection will immediately start to transfer load to the closure head and thereby the remainder of the closure structure which is very rigid due to the dished head design and short hub length.

The "Code acceptable" structural integrity of the degraded heat exchanger both with and without the temporary leak repair device installed is documented in accordance with Code case N-705 which is attached to this MP. Therefore the N-705 Code case ensures acceptable structural integrity of the degraded component even when the gasketed plate is removed during UT to monitor degradation as well as when the leak repair device is fully installed.

Calculation EG-57 stresses are shown in the table below. The table also shows that selected materials are of adequate strength to resist the loads imposed.

10 of 16 STARS- ENG -5001-8.1 09/04112 Page 32

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002 Loads and Material Strength Table Item EG-57 Size Material chosen Material Strength Comments Stress Ex isting hub nut -11,969 psi NA Ex isting base Tensile strengths are Material strength is not mount to hub materials are SA-106 60 ,000 psi and 70 ,000 psi exceeded welds Gr Band SA-515- GR respecti vely for base 70 . material ensuring weld strength is at least 60,000 psi New hub nut 13 ,560 psi 1/8 " minimum Hub nut mounts are Tensile strength is 60,000 Material strength is not mount to swing crossection SA-106 Gr Band the psi for the SA-106 Gr B. exceeded nut welds sw ing nuts are A325 Any weld filler selected will or A193 Gr B7 exceed the calculated material stresses.

Standoffs 18,641 psi V2' thick, 1.5" SA-36 36,000/ 58,000 psi Material strength is not wide and not exceeded greater than 1.5" high Crossmember 15,456 psi 1.25 " square SA-36 36 ,000/ 58,000 psi Material strength is not bar by ~9 " exceeded overall length Crossmember 3105 psi Entire 1.25" SA-36 36 ,000/ 58,000 psi Material strength is not threads shear thickness of exceeded bar is threaded Rod 26,271 psi 112 diameter 11 A-193 B7 125,000 psi minimum Material strength is not by 20 threads tensile strength exceeded per inch Plate 11,683 psi 5/8 " thick by SA-36 36 ,000/ 58,000 psi Material strength is not 1.25" height exceeded and width

8. Material Requirements For optimum sealing a soft gasket should be used due to the slight curvature of the manway hub and roughness in the area of the pinhole leak. In order to meet the low load requirements of N705 1 rubber is the first choice of materials. Other gasket materials may be used provided they meet temperature and pressure requirements 1 compatibility/ will not compress below the recess in the face of the gasket plate/ and will seal with a load not exceeding 1300 pounds. The gasket may be adhered to the gasket plate with a quick drying gasket adhesive (e.g. 3M Super 77 MIN 6371763) to enhance gasket stability. The gasket material 1 as with all the materials in use for this MP will be procured safety-related.

The threaded rod will be carbon steel or an alloy steel. All other structural components of this temporary closure will be carbon steel per the table above.

9. Mechanical Requirements 11 of 16 STARS- ENG -5001-8.1 09/0411 2 Page 33

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002 The temporary repair structure has been evaluated to determine the mechanical loads as documented in item 5 above. The temporary repair device has been evaluated for loads in excess of that allowed by the N705 evaluation load of 1300 pounds.

Calculation EG-57 Rev 000 determined that the temporary repair device is seismically rigid with a natural frequency much greater than 33 hertz.

19. Failure Effects The temporary repair device must meet all the events and accidents for which EEG01A is designed. The forces, including seismic loading, have been calculated in EG-57 and the strength requiremements incorporated into this design.

The potential failures of the temporary repair device include threaded fastener failure, gasket failure, and failure of the welds that hold the device together and attach it to the hub of the closure. The Plant North end cover for this heat exchanger already relies upon threaded fasteners to load a gasket and prevent leakage. Likewise there are numerous existing welds that woud result in leakage should they fail. It is therefore concluded that every one of these failure modes already exist within the current design and the effect of the failure is unchanged when applied to the temporary repair device - a leak.

20. Test Requirements CPCTP) including acceptance criteria Testing and acceptance criteria are provided in the PCTP. The post change testing consists of an Engineering review of "critical" dimensions that ensure EG-57 Rev 000 is bounding before loading the temporary repair device. The acceptance criteria is given in the PCTP. An In-service Leak Test will be performed post installation.
21. Accessibility A portion of this temporary modification will have to be removed for periodic inspection of the degraded pinhole location. Accessibility was discussed with those that will be doing the inspection and ample access is available when the rod and gasket plate are removed to facilitate the inspection.

If the nub nut mount to swingnut welds are left in place, the two affected swingnuts will no longer swing out to the way to facilitate quick head removal. The only impact will be the necessity of completely backing out 12 of 16 STARS- ENG -5001-8.1 09/0411 2 Page 34

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002 the hold down bolt rather than JUSt loosen1ng 1t and sw1ng 1t out of the way to remove the closure head during maintenance. Should the standoffs and crossmember remain in place there is no impact on accessibility due tho them remaining in place.

31. Special Processes Welding will be in accordance with applicable Callaway procedures and the ASME Section XI Code.
43. Operating Experience (External and Internal)

CARS system Review over the past 10 years reveals that there have been many pinhole leaks in the ESW system. This pinhole leak developed from a degraded area that had been noted in a prior heat exchanger inspection. Raw water corrosion of carbon steel piping systems is not unexpected.

INPO An ICES search utilizing "Temporary" and "leak repair" resulted in 236 Operating Experience items. Only #306638 seemed relevant. The incident involved an attempt to use a soft material to stop a small through-wall leak that was unsuccessful and an encapsulation was ultimately installed to stop the leak.

The leak was near a weld joint of an elbow and flange. Due to the location of this leak, there is confidence that the temporary repair device will be successful.

Hazards Review Question # 4 "Seismic" was answered "yes" because a seismic component is being modified. The weight and seismic forces anticipated for this temporary repair is less than 10 pounds and less than 50 pounds static equivalent force. The flooded weight of the heat exchanger is greater than 200,000 pounds. The heat exchanger is therefore not adversely affected. The temporary structure added is rigid per EG-57 Rev 000 and has been designed to meet the bounding conditions of EG-57 Rev. 000.

Question # 10 "ALARA" was answered "yes" because work will take place in the RCA. The work will be on a non-contaminated system and in a low dose area.

Normal work and RP planning is sufficient for installation of this MP.

Programs Review 13 of 16 STARS- ENG -5001-8.1 09/04112 Page 35

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002 Quest1ons # 12 & 13 were marked "yes" because a "Mamtenance Rule" component is being modified. However neither the Maintenance Rule nor the "Equipment Reliability" program is affected and component reliability is not reduced.

Operational and Design Margin With the modification in place, design margin is increased over the current degraded condition because the temporary repair can be credited for leak mitigation restoring UHS volume margin. There is no effect on the operation of EEG01A or any other sse whether the remporary repair is installed or not. Thus it can be concluded that there is no effect on operational margin.

When the temporary repair is partially removed for regular inspection of the pinhole leak location, the plant cannot credit the leak reduction provided by the temporary repair.

Design Basis, ULDBD Review The CCW Heat Exchanger EEG01A transfers all heat absorbed by the CCW system to the ESW system and is listed as "Mission Critical" in the ULDBD. EEG01A is safety-related and thus seismic category I. The heat exchanger is located in a mild environment. EEG01A serves the following passive functions per Director:

  • Transfers heat from Emergency Safety Features systems during LOCA and MSLB
  • Provides safety-related cooling for normal operation and during shutdown
  • Provides cooling to RCP thermal barriers to preclude seal failure WCNOC Applicability Does not apply.
5. FIELD WORK NOTE: There are numerous "critical" dimensions that must be verified by Engineering to ensure the final installation is within the bounds of calculation EG-57 Rev 000. Engineering should be closely consulted as the repair device is being fabricated and installed to ensure final design is acceptable.

General steps:

14 of 16 STARS- ENG -5001-8.1 09/0411 2 Page 36

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002

1. Cut a piece of 1-1/4" square stock 5/8" (+1/16", -0/16") thick and machine gasket recess and drill centering pocket per sketch.
2. Drill and tap a length of 1-1/4" square crossmember at a 4° angle per attached sketches to accept V2" by 20 TPI threaded rod. Drill hole should be precisely centered front-to-back in the square crossmember.
3. Machine flat spot at corresponding 4° angle for jam nut fitup.
4. Cut standoffs and machine/fit them up in the field to keep the crossmember and thus the rod centered over the pinhole leak. The longest edge of the standoff should not exceed 1-1/2" to stay within current stress analysis.
5. Cut V2" x 20 TPI threaded rod and machine tip to an inclusive angle 10 degrees less than that of the centering pocket. (This ensure the tip will bottom in the centering pocket even with some misalignment). Slightly radius the tip to fit the bottom of the centering pocket in the plate.
6. Weld V2" x 20 TPI hex nut to opposite end of threaded rod.
7. Weld standoffs to crossmember. Standoffs should be precisely centered on and perpendicular to the face of the square crossmember they are welded to.
8. Weld the hub nut mount to the swing nuts on the two affected hub nut mounts as shown in attached sketches.
9. Remove paint in the area surrounding the pinhole leak where the gasket will contact the closure hub.
10. Weld crossmember and standoffs to the hub nut mounts maintaining the pointed rod tip centered over the pinhole leak. (Final location of rod tip should be within 3/32" of pinhole leak center upon final assembly and rod must be within 3 degrees of perpendicular to the closure hub surface).
11. Thread a jam nut on to the threaded rod and thread rod into crossmember.
12. Cut and attach a piece if 1" wide by 1" long gasket material to fit the recessed side of the gasket plate. Use an approved adhesive to adhere the gasket to the gasket plate.
13. Place gasketed plate over the pinhole leak and hold it from rotating while the threaded rod is torqued. Tighten the rod to an initial torque of 48 in-lbs if using a rubber gasket. If leakage persists, continue to increase the torque in 12 in-lb increments until leakage stops. DO NOT EXCEED 96 in-lbs. During torquing, stop if any leakage occurs at the closure head 0-ring fit or excessive gasket bulging occurs (rubber gasket material concern only).

Record final torque.

14. Lightly tighten the jam nut on the threaded rod.

Planned FCNs An FCN will revise design documents once this modification is no longer needed to reflect the as-left condition of EEG01A. Additionally, an FCN will be processed if 15 of 16 STARS- ENG -5001-8.1 09/0411 2 Page 37

Attachment B of Enclosure to ULNRC-06092 STARS ENGINEERING DISPOSITION Title EEG01A Temporary Non-Code Leak Repair Mod No./Rev MP 14-0002 the fmal f1eld f1tup of the repa1r dev1ce does not conf1rm to the conceptual des1gn used formulating EG-57 Rev 000 and requires revision to EG-57.

6. CONFIGURATION CONTROL Documentation Updates (Drawings, Calculations, Manuals, Procedures)

Drawing M-072-00001 will be revised to reflect installation of the leak repair modification. Once removed, either completely or partially, the same drawing will be revised via FCN.

Design Integration- (review open mods for potential overlap/impact)

No additional mods were identified that are impacted by MP 14-0002 Equipment Database (Director) Updates None.

Preventative Maintenance (PM) Changes None.

Procurement/Warehouse Changes (Parts Q List)

None.

7.REFERENCES Documentation

References:

M-072-00001 Rev 018 M-072-00022 Rev 001 Equipment Database Component

References:

EEG01A

8. COORDINATION This design has been coordinated with input from planners, construction supervisors and craft personnel.

16 of 16 STARS- ENG -5001-8.1 09/0411 2 Page 38

Retrieved from "https://kanterella.com/w/index.php?title=ML14079A532&oldid=2453387"