ULNRC-05529, CFR50.55a Request: Proposed Alternative to ASME Section XI Requirements for Replacement of Class 3 Buried Piping

CFR50.55a Request: Proposed Alternative to ASME Section XI Requirements for Replacement of Class 3 Buried Piping

ML082140282
Person / Time
Site:	Callaway
Issue date:	07/24/2008
From:	Graessle L AmerenUE, Union Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ULNRC-05529
Download: ML082140282 (13)

Text

AmerenUE P0 Box 620 Cal/away Plant Fulton, MO 65251 July 24, 2008 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 ULNRC-05529 g meen Ladies and Gentlemen:

DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.

FACILITY OPERATING LICENSE NPF-30 10CFR50.55a REQUEST: PROPOSED ALTERNATIVE TO ASME SECTION XI REQUIREMENTS FOR REPLACEMENT OF CLASS 3 BURIED PIPING - (TAC NUMBER MD6792)

References:

1. ULNRC-05434 dated August 30, 2007

2. ULNRC-05490 dated April 17, 2008

3. ULNRC-05517 dated July 10, 2008 In Reference 1 cited above, Union Electric Company (AmerenUE) submitted Relief Request 13R- 10 regarding paragraph IWA-422 1(b) of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI. The relief request, which is still under review by the NRC staff, was requested to support the planned replacement of buried steel piping in Callaway's essential service water (ESW) system with high-density polyethylene (HDPE) piping.

In References 2 and 3, AmerenUE responded to various questions and requests for additional information received from various NRC Branch reviewers. More recently, during a teleconference between AmerenUE and the NRC held on July 17, 2008, the NRC reviewers requested additional clarifying information. In responding to these requests, AmerenUE has revised a few pages of Enclosure 5 that was transmitted to the NRC as part of the letter submitted on July 10, 2008 (Reference 3). In the July 10, 2008 letter, Enclosure 5 provided the NRC with an updated and final version of the relief request document itself, 10CFR50.55a Request Number I3R-10, that had been provided in the initial relief request letter submitted to the NRC on August 30, 2007 (Reference 1). As agreed upon in the July 17, 2008 teleconference (and in lieu a subsidiary of Ameren Corporation

ULNRC-05529 July 24, 2008 Page 2 of resubmitting Enclosure 5 in its entirety), only the revised pages are hereby provided as Attachment 1 to this letter. Note that the revisions on each page have been highlighted.

Subsequent to the teleconference held on July 17, 2008, AmerenUE received an e-mail dated July 21, 2008 from the NRC requesting an additional clarifying information item. The response to this e-mail is also attached to this current letter as .

There are no additional commitments made within this submittal.

If you have any questions on this letter or its attachments, please contact Mr. Scott Maglio at (573) 676-8719.

Very truly yours, Luke H. Graessle Manager, Regulatory Affairs DJW/TBE/nls Attachments: 1 - Revised Pages of Enclosure 5 to letter ULNRC-05517 dated July 10, 2008 2 - Improved Hydraulic Performance Attributed to Use of HDPE Piping

ULNRC-05529 July 24, 2008 Page 3 cc: U.S. Nuclear Regulatory Commission (Original and 1 copy)

Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 Mr. Elmo E. Collins, Jr.

Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Mohan C. Thadani (2 copies)

Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop O-8G14 Washington, DC 20555-2738

ULNRC-05529 July 24, 2008 Page 4 Index and send hardcopy to QA File A160.0761 Hardcopy:

Certrec Corporation 4200 South Hulen, Suite 630 Fort Worth, TX 76109 (Certrec receives ALL attachments as long as they are non-safeguards and may be publicly disclosed.)

Electronic distribution for the following can be made via Responses and Reports ULNRC Distribution:

A. C. Heflin F. M. Diya T. E. Herrmann S. M. Maglio T. B. Elwood L. H. Graessle S. L. Gallagher L. M. Belsky (NSRB)

R. D. Myatt w/o C. R. Kiefer w/o M. D. Brandes w/o J. E. O'Sullivan w/o G. G. Yates w/o D. J. Walker w/o Mr. Ron Reynolds, Director (SEMA)

Mr. Edward Gray, Senior REP Planner (SEMA)

Mr. John Campbell, REP Planner (SEMA)

Ms. Diane M. Hooper (WCNOC)

Mr. Dennis Buschbaum (TXU)

Mr. Scott Bauer (Palo Verde)

Mr. Stan Ketelsen (PG&E)

Mr. Scott Head (STP)

Mr. John O'Neill (Pillsbury Winthrop Shaw Pittman LLP)

Mr. Floyd Gilzow (DNR) to ULNRC-05529 ATTACHMENT 1 REVISED PAGES OF ENCLOSURE 5 TO LETTER ULNRC-05517 DATED JULY 10, 2008

P = internal gage pressure coincident with given service level or loading, psi PD= internal design gage pressure at the specified design temperature. psi lb/ft2 PE = vertical soil pressure loads due to weight cover of earth, Phydro = external hydrostatic pressure, equal to earth plus groundwater pressure plus surcharge load, psi 2 PL = vertical soil pressure due to surcharge loads, lb/ft R = buoyancy reduction factor S = allowable stress, psi, Table 3021-1 TD= Design Temperature, deg F t = nominal pipe wall thickness, in tdesign = minimum required wall thickness, in t fab min = minimum thickness in accordance with ASTM F-714 tmin = pressure design thickness, in W, = weight of contents (equals 0 when empty), lb/ft Wp = weight of pipe per unit length, lb/ft (exclude weight of contained liquid to represent the worst case of an empty pipe)

Ww = weight of water displaced by pipe, per unit length, lb/ft c = coefficient of thermal expansion, 1/°F CSW= circumferential compressive stress in the sidewalls, psi AP = differential pressure due to negative internal pressure, psi ATeq = equivalent temperature rise, deg.F Esoil = maximum soil strain due to seismic wave passage Q = ring deflection

= maximum allowable change in diameter as a per cent of the original diameter, commonly called the change in ring diameter, 3 Table 3031-1 Psaturated = density of saturated soil, lb/ft 3

Pdry = density of dry soil, lb/ft v = Poisson ratio (0.35 for short duration loads (5 min. or less) to 0.45 for long duration loads(greater than 5 min.))

-3012 Design Life (a) The Design Specification shall specify the design life of the system, not to exceed 50 years.

(b) The duration of load shall be specified for each load case, and the HDPE pipe physical and mechanical properties shall be based on the duration of load.

-3016 Design and Service Loading Design loads shall be as defined in ASME Section III, ND-3112.1 through ND-3112.3, except the design factor shall be 0.50. Miner's Rule in accordance with ISO 13760 shall be used to account for operation for 30 days at post-accident conditions and normal operating conditions for the balance of the 40 year design life. Loads applied to buried HDPE pipe shall be defined in the Design Specification, and shall include, as a minimum, the following:

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FaE = axial force range due to the combined effects of seismic wave passage, seismic soil movement, and building seismic anchor motion effects, lb A = cross-section area of pipe at the pipe section where the force is calculated, in ME = resultant moment range due to the combined effects of seismic wave passage, seismic soil movement, and building seismic anchor motion effects, in-lb Z = section modulus of pipe cross section at the pipe section where the moment is calculated, in' S = allowable stress, psi, Table 3021-1 Seismic wave passage, seismic soil movement, and building seismic anchor motions shall be combined by square root sum of the squares or by algebraic sum.

Supplement 3 provides a non-mandatory method for the analysis of seismic wave passage, seismic soil movement, and building seismic anchor motion effects,

-3060 Design for Future Internal Access Removable spools will be installed that would provide future access to the ID surfaces in each replacement line should suitable remote examination equipment be developed.

-4000 FABRICATION AND INSTALLATION

-4100 GENERAL REQUIREMENTS

-4110 Scope This Article provides the requirements for the installation of PE piping and fittings. Methods of installation shall be by thermal fusion and flanged fittings. Use of threaded or adhesive joints with HDPE material is not permitted. All metallic interface components will be installed following the requirements of ASME Section III, Subsection ND.

-4120 Examinations

[Deleted]

-4130 REPAIR OF MATERIAL HDPE material originally accepted on delivery in which defects exceeding the limits of -2300 are known or discovered during the process of fabrication or installation is unacceptable. The HDPE material may be used provided the defective area can be physically removed from the material or repaired in accordance with -2300.

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AmerenUE shall maintain records of qualified fusing procedures and the fusion machine operators qualified by them, showing the date and results of tests and the identification mark assigned to each fusing operator. These records shall be reviewed, verified, and signed by an authorized individual and they shall be accessible to the Authorized Nuclear Inspector.

-4323 Fusing Prior to Qualification Fusing Procedure Specification (FPS) shall be qualified as required by Supplement 9 prior to their use. Only fusing operators who are qualified in accordance with -4320 and Supplement 9 shall be used.

-4324 Transferring Qualifications The FPS qualifications and performance qualification tests for fusion machine operators shall not be transferred to another organization.

-4330 Requirements for Fusing Procedure Qualification Tests

-4331 Conformance to Supplement 9 Requirements All fusing procedure qualification tests shall be in accordance with the requirements of Supplement 9 as supplemented or modified by the requirements of this document.

-4332 Preparations of Test Coupons and Specimens Removal of test coupons from the fusion test coupons and the dimensions of specimens made from them shall conform to the requirements of Supplement 9.

-4340 Performance Demonstration

-4341 AmerenUE will produce six (6) fusion joint test coupons of 36NPS DR 9.5 and six (6) fusion joint test specimens of 4NPS DR 9 material on each model of fusion machine carriage expected to be used in production for the respective size of piping as a performance demonstration. Three (3) of these fusions on each machine will target minimum temperature and interfacial pressure using maximum heater removal times, and three (3) will target maximum temperature and interfacial pressure using minimal heater removal times - considering production limits, machine capabilities and the limits of the AmerenUE Fusion Procedure Specification.

-4342 A minimum of four (4) specimens will be cut from each fusion joint coupon approximately 90 degrees apart and tensile-tested to verify that the fusion joint is stronger than the pipe. Testing will be performed by commercial plastics industry suppliers without a 10 CFR 50 Appendix B quality program, but all testing will be overseen by AmerenUE representatives, and the test records will be retained in permanent Callaway records.

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-4343 High speed impact tensile testing for the 4NPS and 36 NPS specimens will be performed in accordance with QF-131. If this testing is determined to be inconclusive for the 36NPS specimens due to fast tensile machine capability and the need to test segmented specimens, tensile testing for the 36 NPS specimens will be performed with full-section specimens consistent with ASTM Specification D638, "Standard Test Method for tensile Properties of Plastic."

-4400 RULES GOVERNING MAKING FUSED JOINTS

-4410 General requirements

-4411 Identification, Storage, and Handling of HDPE Materials AmerenUE is responsible for control of the HDPE materials that are used in the fabrication and installation of components (-4120). Suitable identification, storage, and handling of HDPE material shall be maintained.

-4412 Cleanliness and Protection of Surfaces to Be Fused The surfaces of the heater used for fusing shall be free of scale, rust, oil, grease, and other deleterious material. The work shall be protected from deleterious contamination and from rain, snow, and wind during fusing operations. Fusing shall not be performed on wet surfaces.

Fusing will not be performed below 50 deg F. Any fusing performed below ambient temperature of 50'F will require an environmental enclosure to be placed over the work area to control temperature.

-4420 Rules For Making Fused Joints

-4421 Fused Joint Fit-up Requirements (a) Components of different outside diameters shall not be fused together.

(b) The alignment of components for open butt fusion joints will be held in position by the fusing machine, allowable surface mismatch shall be less than 10% of the minimum wall thickness of the components being fused, and the remaining joint thickness shall not be less than the required as-fabricated minimum wall thickness per ASTM F714 - unless evaluated and determined to be acceptable considering the remaining wall thickness c) To fuse components with differing DR's, the component with the smaller DR shall be countered-bored and tapered to meet the wall thickness of the component with the larger DR and shall comply with Figure -4421.3-1 18

dimensions and relative locations, simulating flaws expected to occur in unacceptable joints.

(c) Personnel performing TOFD examinations will be qualified in accordance with SNT-TC-1A (Level II, minimum) or equivalent, as determined by AmerenUE.

(d) Acceptance criteria will be evaluated and refined by AmerenUE, and will be based on industry standards (e.g. B31 piping codes). The current acceptance criteria require that any unbonded area in the joint, found as a result of the TOFD, is cause for rejection.

(e) All TOFD joint examination records shall be retained as permanent records.

-5300 ACCEPTANCE STANDARDS

-5310 General Requirements Unacceptable joints shall be removed. Repair of unacceptable joints is not permitted.

-5320 VisualExamination Acceptance Criteria of external surfaces

-5321 Thermal fusion butt joints shall meet the following:

(a) Joints shall exhibit proper fusion bead configuration, see Supplement 5.

(b) There shall be no evidence of cracks or incomplete fusion.

Except for mitered joints, joints shall not be visually angled or off-set. The ovality offset shall be less than 10% of the minimum wall thickness of the fused components provided the remaining joint thickness is not be less than the required as-fabricated minimum wall thickness per ASTM F714 - unless evaluated and determined to be acceptable considering the remaining wall thickness.

(c) The cleavage between fusion beads shall not extend to or below the outside diameter pipe surface (see Figure -5321-1).

(d) For mitered joints, the beads may flare out instead of roll back to the pipe surface, and/or may exhibit multiple beads or heavy beads with no cleavage. In either case, there must be evidence of melt flow around the complete interior and exterior circumference of the joint. Refer to Supplement 5.

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((b)

Pipe (Cross Section Woew) HPEPipe (Cross Section View)

Visually Acceptable - Uniform Bead around pipe Visually Acceptable - Non-uniform Bead around pipe (c) (d) Cleavage tip shall 11o meet or extend t -DPE Pipe (Cross Section Wow) HOPE Pipe (Cross Section View)

Visually Acceptable - Non4m[foml Bead around pipe Visually Unacceptable - Now-uniform/Ualform Bead Localize diameter mismaltct less than 10% ol the wall around pipe - V-Groove too deep at pipe-tangent FIGURE -5321-1 (e) Review the data acquisition record for the joint and compare it to the Fusion Procedure Specification (FPS) to ensure the proper parameters and procedures were followed in making the fused joint, see paragraph -5330.

-5330 Process Verification The data acquisition record for each joint shall be reviewed and compared to the Fusion Procedure Specification (FPS) to ensure the proper parameters and procedures were followed in making the fused joint.

-5500 QUALIFICATION OF NONDESTRUCTIVE EXAMINATION PERSONNEL

-5510 General Requirements

[Deleted]

-5520 Personnel Qualification Requirements (a) Personnel performing visual examinations required by -5200 (a) and (b) shall be qualified and certified as a VT-I in accordance with IWA-2000 and shall receive the required training and evaluation in paragraph -5100(b) & (c).

24 to ULNRC-05529 Page 1 of 2 ATTACHMENT 2 Improved Hydraulic Performance Attributed to Use of HDPE Piping NRC Request for Additional Clarifying Information:

In the public meeting conducted at the NRC offices on July 1, 2008, there was discussion about the improved hydraulic performance that would be effected for the ESW system by the HDPE piping. Provide a summary/explanation of that improved hydraulic performance.

AmerenUE Response:

The following information is extracted from publicly available documentation (Plastics Pipe Institute - PPI- http://plasticpipe.org). The information supports the improved hydraulic performance of HDPE pipe.

1) From the PPI Handbook for HDPE piping: "Hydraulically Efficient - For water applications, HDPE pipe's Hazen Williams C factor is 150 and does not change over time. The C factor for other typical pipe materials such as PVC or ductile iron systems declines dramatically over time due to corrosion and tuberculation or biological build-up. Without corrosion, tuberculation, or biological growth HDPE pipe maintains its smooth interior wall and its flow capabilities indefinitely to insure hydraulic efficiency over the intended design life."

2) From PPI Technical Report TR-14, "Water Flow Characteristics Of Thermoplastic Pipe":

a. "During the past 30 years, the use of thermoplastic piping in water and sewer systems has increased significantly. There are many reasons for this wide acceptance, but one of the primary characteristics which makes thermoplastic piping attractive to designers is the low resistance to flow that this piping offers."

b. "...a Hazen-Williams Flow Factor of 150 is recommended for thermoplastic pipes. This value is based upon laboratory tests and field experience. Test results have yielded higher values in the range of 155 to 165, but the use of a value of 150 is conservative in nature and, therefore, aids in providing a further factor of safety to the design."

to ULNRC-05529 Page 2 of 2

c. "Contrary to the experience with some other piping products, no allowance for corrosion and, therefore, subsequent lowering of flow capacity, has to be included in the Tables that are used in this report. Field experience in North America and Europe over the past 30 years indicates that the flow characteristics in older thermoplastic lines are essentially unchanged over time.

The use of a higher Hazen-Williams coefficient of 150 for HDPE, versus the Hazen Williams coefficient of 100 for new steel piping (older piping with corrosion typically has a lower Hazen Williams coefficient of 80-90), and the lack of corrosion for the HDPE reveals the decreased resistance to flow afforded by the HDPE material.