ML102920170

Email - Attachments: Response to NDT Question from Nrr.Pdf 059169_NDT Qualification Letter_1 1-11-09. Pdf Request 10.docx, Request 11 .Docx, Request 16.docx

ML102920170
Person / Time
Site:	Crystal River
Issue date:	11/24/2009
From:	Lake L NRC/RGN-II
To:	Ali Rezai Office of Nuclear Reactor Regulation
References
FOIA/PA-2010-0116
Download: ML102920170 (20)

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r-Lake. Louis From: Lake, Louis Sent: Tuesday, November 24, 2009 8:23 AM To: Rezai, Ali Cc: Chan, Terence; Franke, Mark Attachments: Response to NDT Question from NRR.pdf; 059169NDT Qualification Letter_1 1-11-09.pdf; Request 10.docx; Request 11 .docx; Request 16.docx I ,' / ).J 7 Ali;

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I understand that you have been assigned to review the NDT activities at Crystal River.

To facilitate your re~iew, attached are the responses provided by Crystal River staff to your questions on the NDT techniques used for identification of the de-lamination in the CR containment. I included responses I received to some of the related questions asked by the SIT team and on the personnel qualification issue. I have resumes/individual qualification information (not attached) for each NDT technician that was on site. Let me know if you need this info.

Note that there is no industry standard on how to qualify these NDT techniques. The NDT results were subsequently confirmed by core bores in the containment surface.

If needed, we can set up a conference call next week to resolve any questions you may have. I will out of the office beginning today at 11:00am and will return on Monday, Nov. 30.

Louis Lake SIT lead Louis.Lake@nrc.gový 404-562-4683 I

~IP (9~

Reply to NRC Questions provided from Lou Lake on 11/13/09 to Condition Assessment Team Lead.

1. Technical Justification:

General Impulse Response (IR) technique was developed from the vibration method for pile integrity testing and has been known variably as the transient dynamic response (TDR),

mobility or impedance method for many years. The method has been extended to the inspection of concrete structures other than piles, particularly plate-like elements such as floor slab, walls and large cylindrical structure. Theoretical researches and application case studies about Impulse Response method have been well published. A list of recent publication references about IR method for concrete structural evaluation is attached. A recent research in theoretical interpretation of IR method is presented by Ottosen, N.S.,

M. Ristinmaa and A.G. Davis in 2004 (Ref 1)

Average Mobility is a principal parameter that IR test produces. The Average Mobility is defined as the structural surface velocity responding to the impact divided by the force input [a measure of flexibility]. The mean mobility value over the 0.1-1 kHz range is directly related to the modulus, density and most importantly the thickness of a plate-like element. In general, presence of significant voiding or an internally delaminated or unbonded layer will result in an increased average mobility value. On the other hand, a sound concrete element without distress will produce a relatively low average mobility value. The test results can be analyzed and presented in the form of contour plots. The suspect areas can be identified through a scaled color scheme. In practice, the IR method is utilized on a comparative basis, which allows the engineer to compare the difference in dynamic responses between test areas within the same structure or between similar structures. The different responses are correlated to the condition via intrusive sampling such as core bore or chipping at the beginning stage of the test program for the specific structure.

The IR test method for concrete structure evaluation is in the process of being standardized by ASTM Committee C09 (Concrete & Concrete Aggregate) and its sub-committee C09.64 (Nondestructive In-place Testing). In addition, ACI Committee 228 (Nondestructive Testing) is revising the committee report 228.2R "Nondestructive Test Methods for Evaluation of Concrete in Structures" which will include IR testing for concrete structure evaluation in addition to pile integrity evaluation.

Impact-Echo (IE) testing is well known NDT method in concrete industry. Besides hundreds of published papers in 1980s and 1990s, its theory and application are collectively summarized in a book by Prof. Sansalone, M. and W.B. Streett of Connell University in 1997, "Impact-Echo: nondestructive evaluation of concrete and masonry,"

published by Bullbrier Press, Ithaca, NY. The IE test method is included in ACI report 228.2R-98, and also ASTM ASTM C1383 - 04 "Standard Test Method for Measuring the P-Wave Speed and the Thickness of Concrete Plates Using the Impact-Echo Method".

When evaluating presence of delamination in a plate-like structure, the stress wave generated by the impact will be reflected by the boundary such as a delamination or back wall of the structure and the echo signal received by the transducer. The typical

speed of stress wave transmission in modern concrete is approximately 4,000 m/s.

Therefore by obtaining the resonant frequency of the effective thickness under the test point, the depth of the thickness can be calculated. If no delamination is present, the full wall thickness is obtained.

a. Detection of delamination in a plate-like concrete element is one principal application of IR and IE methods. The application of these methods to detect delaminations is directly analogous to thickness evaluation. When a plate like structure contains a significant delamination it behaves like two independent plates. The effective thickness is defined as distance from the test surface to a crack parallel to the surface if delaminated, or the full structural thickness if no internal separations exist. The average mobility value of a structure is somewhat proportional (inversely) to the cube of the thickness (moment of inertia 1/12bh 3), making the response from an area with a delamination at 10 inches several times higher than the response from a 42 inch thick structure. The presence of delamination will effectively reduce the thickness of wall or slab responding to the impact, which results in a drastically increased average mobility value. This is in consistence with the test results obtained on the containment wall structure in Crystal River. The typical mobility value in areas where delaminations were noted typically exceeded 1.0 (up to about 15 or so depending on the depth of delamination) while in solid concrete areas the value is typically below 0.4. There is large difference in structural response to the hammer impact when comparing a 42 inches wall in solid concrete area to an approximately 6 to 12 inches thick delaminated layer. The difference in effective thickness resulted in an approximately 5 to 10 times difference in average mobility values.

Limitations:

The potential limitations about IR testing in detecting delamination in plate-like structure include: 1) the absolute size or width of the crack could not be evaluated, other method such as core hole examination using boroscope shall be used; 2) the absolute depth of the delamination from surface can not be readily determined, the depth can only be ascertained by coring or other NDT method; 3) The depth of influence is typically around 20 inches.

b. The submitted method description was an outdated document and shall be replaced.

Use of IR testing to evaluate concrete structure has been constantly used in the industry in the past 15 years. A list of more recent publications related to its application (evaluating presence of delamination or other internal defects) is located in Enclosure 1.

c. Use of IE testing to evaluate delamination is analogousto thickness measurement.

When delamination is present, instead of measuring the full wall thickness, the test measures the thickness of the delaminated layer which is separated from the substrate concrete.

Since its inception, the IE test theory has not changed, the book by Sansalone and Streett is still the most complete reference to this technique. The potential limitations of IE testing in evaluating the delamination in containment wall structure include: 1) relative slow process which requires laying out the PT ducts and reinforcement prior to testing; 2) the test data is affected by the surrounding tendons in the vicinity of test points which frequently cause false-positive indications of delamination. Due to this limitation, core bore sampling, instead of IE testing, to verify / confirm the IR test results are constantly used in this testing program.

2. Qualifications:

a. Separate files provided with qualifications for individuals from CTL.

b. Honggang Cao, PE, possesses certificate of ASNT Level III in Ultrasonic Testing (No.

148008, expires Sep, 2012).

c. Honggang Cao, PE, has more than 12 years experience using IE and 8 years experience using IR techniques. (Sample of previous report will be made available to NRC once the client approves the release.)

d. See enclosure 2 3, Currently there is no agency in industry responsible for approving concrete NDT equipment.

4. The IR test method for concrete structure evaluation is in the process of being standardized by ASTM Committee C09 (Concrete & Concrete Aggregate) and its sub-committee C09.64 (Nondestructive In-place Testing). In addition, ACI Committee 228 (Nondestructive Testing) is revising the committee report 228.2R "Nondestructive Test Methods for Evaluation of Concrete in Structures" which will include IR testing for concrete structure evaluation in addition to pile integrity evaluation. The IE test method is included in ACI report 228.2R-98, and also ASTM ASTM C1 383 - 04 "Standard Test Method for Measuring the P-Wave Speed and the Thickness of Concrete Plates Using the Impact-Echo Method". Application of both methods include detection of delamination.

5. a Interaction of propagating stress wave with reinforcing steels and / or tendons are not significant factors to IR testing on this containment wall structure, comparing to the influence from a delamination at 6 to 14 inches depth. Trial testing along known tendon lines or between a pair of two circumferential tendons using IR indicated marginally higher mobility values (0.2 to 0.6 or so). The influence of reinforcement and tendons in the structure has generally less impact for IR than it would for IE test. The signal response in IR testing will be dominated by presence of delamination, if any. It makes it ideal to evaluate the presence of delamination without having to layout locations of tendon and reinforcing bars prior to the testing in a time critical project. As stated previously, the IE testing will be affected by presence of tendons in the vicinity of test point. It may be difficult to analyze a complex signal obtained near unbonded tendons or false positive may result. Therefore, it is important to layout locations of both circumferential tendons and vertical tendons prior to the IR testing. This is also one of the main reasons that IR was chosen as a primary method to evaluate delamination in the containment wall structure. A large number of core samples removed from the structure based on the IR test results have strongly supported the accuracy of the technique in this application.

b. No stress wave methods are effective to detect multiple layers of delamination in concrete. Essentially all energy is reflected back at the first delamination, making detection of lower delaminations unlikely.

c. The IR test is particularly sensitive to delaminations because it does not rely on the presence of an air gap to cause a reflection. The flexural response of the delaminated layer will change significantly even if the structural sections are in intimate contact.

According to Sansalone and Streett, the minimum delamination size which will interrupt the stress propagation in IE testing is approximately 0.08 mm.

d. The useful frequency range for IR testing is approximately 0.1 kHz to 1 kHz. The important frequency range for IE testing is typically between 2 kHz and 40 kHz.

6. b. type of impactor: IR - 1 kg hammer with load cell from PCB (model # 086D20 or 086M91); IE - ball bearing size range from, 5mm to 12 mm.

" Distance range: not critical. Typically from 18 to 24 inches.

Geophone: SM-6 o Power sources: power from laptop computer through USB connection o Max depth: IR - approximately 20 inches.

IE - by changing the size of impactor, the delamination is detectable within 42 inches wall o Environmental conditions will not significantly affect the IR or IE results.

Ref: 1: Ottosen, N.S., M. Ristinmaa and A.G. Davis. "Theoretical Interpretation of Impulse Response Tests of Embedded Concrete Structures". Journal of Engineering Mechanics, ASCE September 2004.

Enclosure 1

IMPULSE RESPONSE REFERENCES Significant and more recent references:

1. Paquet, J. 1968. "btude vibratoire des pieux en b~ton: r~ponse harmonique. (Vibration study of concrete piles: harmonic response)." Annls. Inst. Tech. Bdtim., (France), 2 1st year, 245, 789-803. English translation by Xiang Yee in Master of Eng. Report, University of Utah, 1991, 33-77.

2. Briard, M., 1970. "Contr6le des pieux par la mithode des vibrations (Pile Control by the Vibration Method)," Annls. Inst. Tech. Bdtim., (France), 23rd Year, 270, June, 105-107.

3. Gardner, R.P.M. and G.W. Moses, 1973. "Testing Bored Piles formed in Laminated Clays", Civ. Engrg. And Public Works Rev., 68 (Jan.), London, England, 60-83.

4. Davis, A.G. and C.S. Dunn, 1974. "From Theory to Experience with the Nondestructive Vibration Testing of Piles". Proc. Inst. Civ. Engnrs. Part 2, Vol. 57, paper 7764, 571-593.

5. Discussion published in Proc. Inst. Civ. Engnrs. 1975, Part 2, Vol. 59, 867-875.

6. "Esso's Giant Oil Tanks - a question of more haste, less speed', New Civ. Engr., 1974, Inst. Of Civ. Engrs., London, England, 81(Feb.), 28-38.

7. Davis, A.G. and S.A. Robertson, 1975. "Economic Pile Testing". Ground Engng Vol. 8, No. 3, 40-43.

8. Robertson, S.A., 1976. "Vibration Testing", The Consulting Engineer (UK), Jan. 1976, 36-37.

9. Davis, A.G. and S.A. Robertson, 1976. "Vibration Testing of Piles". Struct. Engnr. Vol.

54, No. 6, A7.

10. Paquet, J. and M. Briard, 1976. "Contr6le non destructif des pieux en baton (Nondestructive Control of Concrete Piles)", Annls. Inst.Tech. Bdtim., (France), 2 9 th year, 337, 50-79.

11. Weltman A.J., 1977. "Integrity Testing of Piles: A Review", Construction Industry Research and Information (UK), Report PG4, Technical Guide No. 18, Sept. 1977, 36 pp.

12. Document Technique Unifid (D.T.U.), 1978. "Travaux de FondationsProfondes pour le Bdtiment (Deep Foundation Works for Buildings)", French Building Code D.T.U. 13.2, Centre Scientifique et Technique du Batiment, Paris, France.

13. Higgs, J.S. and S.A. Robertson, 1979. Integrity Testing of Concrete Piles by Shock Method", Concrete (UK), 13, No. 10, Oct., 31-33.

14. Guillermain, P. 1979. Contribution 6 l'interprbtation g~otechnique de 1'essai d'imp~dance mdcanique d'un pieu (Contribution to the Geotechnical Interpretation of the Mechanical Impedance Test on a Pile)", Ph. D. Thesis, Universitd Pierre et Marie Curie, Paris, France.

15. Davis, A.G. and P. Guillermain, 1979. "Interpretationg~otechnique des courbes de response d'une excitation harmonique d'un pieu" (The Geotechnical Interpretation of the Response of a Pile to Harmonic Excitation). La R6vue Frangaise de Gdotechnique (France) No. 8, 15-2 1.

16. Davis, A.G. and P. Guillermain, 1980. "La vibration des pieux: interpretations g~otechniques" (Pile Vibration: Geotechnical Interpretation.) Annales de 1'ITBTP (France) No. 380, 71-96.

17. Davis, A.G., 1981. "The Nondestructive Testing of Piles by Mechanical Impedance",

Proc. 10th Int. Conf. Soil Mech. & Found. Engng., Stockholm, July 1981, Session 8 Vol.

2.

18. Robertson, S.A., 1982. "Nondestructive Control ofDeep Foundations- New Techniques and Recent Experiences", Regional Symposium on Underground Works and Special Foundations, Singapore, March 1982, 7 pp.

19. Stain, R.T., 1982. "Integrity Testing", Parts I and II, Civil Engineering (UK), Apr., 55-59

& May, 77-87.

20. S.A. Robertson, 1982. "Integrity and Dynamic Testing of Deep Foundations in S.E.

Asia", Proc 7th Southeast Asian Geotechnical Conf., Hong Kong, Nov. 1982, 403-421.

21. Stain, R.T. and A.G. Davis, 1983. "Nondestructive Testing of Bored Concrete Piles -

Some Case Histories",Proc. Int. Conf. on Nondestructive Testing, London, Nov. 1983, 77-87.

22. Swann, L.H., 1983. "The Use of Vibration Testing for the Quality Control ofDriven Cast In-situ Piles ", Proc. Int. Conf. on Nondestructive Testing, London, Nov. 1983, 113-123.

23. Davis, A.G., 1985. "Nondestructive Testing ofPiles Founded in Glacial Till - Analysis of over 30 Case Histories", Proc. Int. Conf. Construction in Glacial Tills & Boulder Clays, Edinburgh, March 1985, Vol. 1, 193-212.

24. Forde, M.C., H.F.C. Chan & A.J. Batchelor, 1985. "Acoustic and Vibration NDT Testing of Piles in Glacial Tills and Boulder Clay", Proc. int. Conf. Construction in Glacial Tills

& Boulder Clays, Edinburgh, March 1985, Vol. 1.

25. Pederson, C.M. and L.J. Senkowski, 1986. "Slab Stabilization of PCC Pavements",

Paper presented at TRB Annual Conference, Washington, D.C. Jan. 1986.

26. Davis, A.G., 1987. "Application of Dynamic Test Methods to the Evaluation of Bridge Structures", 1st NATO USA-European Workshop on Bridge Evaluation, Repair &

Rehabilitation, St. Rdmy-les-Chevreuses, France, July 1987, 11 pp.

27. Davis, A.G. and B.H. Hertlein, 1987. "Nondestructive Testing of Concrete Pavement Slabs and Floors with the Transient Dynamic Response Method" Proc. Int. Conf.

Structural Faults & Repair, London, July 1987, Vol. 2, 429-433.

28. Lilley, D.M., W.M. Kilkenny & R.F. Akroyd, 1987. "Investigation of Pile Integrity of Pile Foundations using a Vibration Method", Proc. Int. Conf. Found. and Tunnels, Engrg. Tech. Press, Edinburgh, Scotland, Vol. 1, 177-183.

29. Williams, H. and R.T. Stain, 1987. "Pile Integrity Testing - Horsesfor Courses", Proc.

Int. Conf. Found. and Tunnels, Engrg. Tech. Press, Edinburgh, Scotland, Vol. 1, 184-191.

30. Ellway, K., 1987. "PracticalGuidance on the use of Integrity Tests for the Quality Control of CastIn-situ Piles ", Conf. Found. and Tunnels, Engrg. Tech. Press, Edinburgh, Scotland, Vol. 1, 228-234.

31. Chan, H.F.C., C. Heywood & M.C. Forde, 1987. "Developments in Transient Shock Pile Testing", Conf. Found. and Tunnels, Engrg. Tech. Press, Edinburgh, Scotland, Vol. 1, 245-261.

32. Olson, L.D. and C.C. Wright, 1989. "Nondestructive Testing of Deep Foundationswith Sonic Methods ", Foundation Engineering: Current Principles and Practices, ASCE, Vol.

2,1173-1183.

33. Davis, A.G., "CEBTP and the English Channel Tunnel" TRB Annual Conf.,

Washington, D.C., Jan. 1990, 11 pp.

34. Davis, A.G. and B.H. Hertlein, "Assessment of BridgeDeck Repairs by a Nondestructive Technique", 2 nd NATO USA-European Workshop on Bridge Evaluation, Repair &

Rehabilitation, ASCE Struct. Conf., Baltimore, Apr. 1990, 229-233.

35. Scull, T.P. and A.G. Davis, 1990. "Experiences in Nondestructive Testing by Impulse Radar and Impedance Methods in the Evaluation of Concrete Highways ", 6 th Int Symp.

on Concrete Roads, Madrid, Oct. 1990, 103-112.

36. Hertlein, B.H. and A.G. Davis, 1991. "Pavement Performance Data: an attempt to relieve the Log Jam ", Paper presented at TRB Annual Conf., Washington, DC, Jan. 1991, 26 pp.

37. Davis, A.G. and B.H. Hertlein, 1991. "The Development of Nondestructive Small Strain Methods for Testing Deep Foundations", Paper No. 910243 presented at TRB Annual Conf., Washington, D.C., Jan. 1991, 23 pp.

38. Paquet, J., 1991, "A New Methodfor Testing Integrity of Piles by Dynamic Impulse: The Impedance Log" (in French), Int. Colloquium on Deep Foundations, Ecole des Ponts et Chaussres. Paris, France, March, 1-10.

39. Nazarian, S., M. Baker and R. Smith, 1991. "Measurement Concepts and Technical Specifications of Seismic Pavement Analyzer". Strategic Highway Research Program, Washington, D.C.

40. Reddy, S. 1992, "Improved Impulse Response Testing: Theoretical and Practical Validations", Master of Science Thesis, University of Texas at El Paso (Director, S.

Nazarian), 219 pp.

41. Nazarian, S and M. Baker, 1992 "A New Nondestructive Testing Device for Comprehensive Pavement Evaluation". Proc. Conf. Nondestructive Evaluation of Civil Structures and Materials, University of Colorado at Boulder, May 1992 (Ed. Suprenant, Noland & Schuller), 437-452.

42. Rix, G.J., L.J. Jacobs & C.D. Reichert, 1993. Evaluation of Nondestructive Test Methods for Length, Diameter and Stiffness Measurements on DrilledShafts ", Paper No. 930620 presented at Transportation Research Board Annual Meeting, Washington, D.C., Jan., 19 pp.

43. Davis, A.G., 1993. "Evaluationof the Integrity of Some Large Concrete Structures using NDT", A.C.I. Spring Convention, Vancouver B.C., Committee 228 Session on Location of Flaws in Concrete using NDT, March 1993, 17 pp. published in: Innovations in Nondestructive Testing of Concrete, ACI SP-168, Ed. S. Pessiki & L.Olson, 1997, 333-356.

44. Baker, C.N. Jr., Drumwright, E.E., Briaud, J-L., Mensah-Dumwah, F. and Parikh, G.,

1993. "Drilled Shafts for Bridge Foundations." FhwA Pub. No. FHWA-RD-92-004.

Federal Hwy. Administration (FhwA), Washington, D.C.

45. Nazarian, S, M.R. Baker and K. Crain, 1993. "Development and Testing of a Seismic Pavement Analyzer". Research Report H-375, Strategic Highway Research Program, Washington, D.C., 165 pp.

46. Davis, A.G., 1994. "Novel Nondestructive Techniques for the Evaluation of Large Concrete Structures", Struct. Mat. & Tech.: an NDT Conf., Atlantic City, February 1994,99-103.

47. Davis, A.G., 1994. "Nondestructive Testing of Wood Piles", Int. Conf. Wood Poles &

Piles, EDM and Colorado State University, Fort Collins, March 1994,94-101.

48. Davis, A.G., 1994. "The Integration of Nondestructive Evaluation in the Maintenance of our Concrete Infrastructure", XXIII Pan-American Engineering Convention - Theme:

Modernization of Engineering in the Conservation of Facilities. Pan-American Union of Engineers Association, Acapulco, Mexico, July 1994.

49. Davis, A.G., 1995. "NondestructiveEvaluation of Existing Deep Foundations".J. Perf.

Constr. Fac., ASCE, Feb. 1995, 9(1), 57-74.

50. Davis, A.G., 1995. "Evaluation of Deep Foundations Beneath Buildings Damaged during the 1994 Northridge Earthquake", Proc. 31st Symp. Eng. Geol. & Geotech.

Engng., Logan, UT, March 1995, 171-179

51. Davis, A.G. and B.H. Hertlein, 1995. "Nondestructive Testing of Concrete Chimneys and Other Structures ", Proc. Conf. Nondestructive Evaluation of Aging Structures and Dams, S. Nazarian & L. Olson, Ed., Proc SPIE 2457, 129-136, Oakland, CA, June 1995.

52. Davis, A.G., B.H. Hertlein, M.K. Lim and K. Michols, 1996. "Impact-Echo andImpulse Response Stress Wave Methods: Advantages and Limitations for the Evaluation of Highway Pavement Concrete Overlays ". Conf. Nondestructive Evaluation of Bridges and Highways, S.B. Chase, Ed., Proc SPIE 2946, 88-96, Scottsdale, AZ, December 1996.

53. Hertlein, B.H. and A.G. Davis, 1996. "Performance-basedand Condition-basedNDTfor Predicting Maintenance Needs of Concrete Highways and Airport Pavements". Conf.

Nondestructive Evaluation of Aging Aircraft, Airports and Aerospace HardWare, R.D.

Rempt and A.L. Broz, Ed., Proc SPIE 2945, 273-28 1, Scottsdale, AZ, December 1996.

54. S. Nazarian, S. Reddy, "Study of parameters affecting Impulse Response method",

Journey of Transportation Engineering, July/August, 1996.

55. Davis, A.G., 1997. "How NDE can help Adjusters in Property Loss and Construction Defects Cases ". Colorado State Loss Adjusters Journal, February 1997.

56. Davis, A.G., 1997. "EvaluationofDeep Foundationsbeneath Buildings damaged during the 1994 Northridge Earthquake". Innovations in Nondestructive Testing of Concrete, ACI SP-168, Ed. S. Pessiki & L. Olson, May 1997, 319-332.

57. Davis, A.G. and B.H. Hertlein, 1997. "Evaluation of the Integrity of some Large Concrete Structures using NDT". Innovations in Nondestructive Testing of Concrete, ACI SP-168, Ed. S. Pessiki & L. Olson, May 1997, 333-356.

58. Davis, A.G., J.G. Evans and B.H. Hertlein, 1997. "Nondestructive Evaluation of Radioactive Concrete Waste Tanks ". J. Perf. Constr. Facilities, ASCE, Vol. 11, No. 4, November 1997, pp. 161-167.

59. Davis, A.G., 1997. "A Place for Nondestructive Evaluation in the Maintenance of our Concrete Infrastructure".Materials Evaluation, Vol. 55 No. 11, 1234-1239, November 1997.

60. Davis, A.G. and J. Kennedy, 1998. "Impulse Response Testing to Evaluate the Degree of Alkali-Aggregate Reaction in Concrete Drilled Shaft Foundations under Electricity Transmission Towers ". Conf. Nondestructive Evaluation of Utilities and Pipelines, Proc SPIE 3398, Paper 21, San Antonio, TX, April 1998.

61. Hertlein, B.H. and A.G. Davis, 1998. "Locating Concrete ConsolidationProblems using the Nondestructive Impulse Response Test ", American Concrete Institute Fall Convention, Los Angeles, CA, October 25, 1998.

62. American Concrete Institute Report ACI 228.2R-98, "Nondestructive Test Methods for Evaluation of Concrete in Structures ". ACI, Farmington Hills, Michigan, 1998, 62 pp.

63. Davis, A.G., 1999. "Assessing the Reliability of Drilled Shaft Integrity Testing",

Transportation Research Board Record, February 1999.

64. Davis, A.G., "The Nondestructive Impulse Response Test in North America: 1985-2001 ".

NDT&E International, 36 (2003), 185-193.

65. Michols, K.A., A.G. Davis and C.A. Olson, "Evaluating Historic Concrete Bridges".

Concrete Repair Bulletin, Vol. 14, No.4, July/August 2001, 5-9.

66. Corley, W.G. and A.G. Davis, "Forensic Engineering Moves Forward". Civil Engineering, June 2001, Vol. 71 No. 6, 64-65.

67. Ottosen, N.S., M. Ristinmaa and A.G. Davis. "Theoretical Interpretation of Impulse Response Tests of Embedded Concrete Structures". Journal of Engineering Mechanics, ASCE, September, 2004.

68. Davis, A.G., and C. G. Petersen, "Nondestructive Evaluation of Prestressed Concrete Bridges using Impulse Response". International Symposium (NDT-CE 2003), Non-Destructive Testing in Civil Engineering 2003.

69. Davis, A.G., M.K. Lim and C. Germann Petersen, "Rapid andEconomical Evaluation of Concrete Tunnel Linings with Nondestructive Impulse Response and Impulse Radar".

Keynote Address, Conference on Structural Faults and Repair 2001, London U.K., July 2001.

70. Gentry, T.A. and A.G. Davis, "IntegratingAdvanced Evaluation Techniques with Terra Cotta Examinations". ASTM Symposium, STP 1444 Building Facade Maintenance, Repair and Inspection, October 12-13, 2002, Norfolk Virginia, 13 pp.

71. Farahmandpour, K., V.A. Jennings, T.J. Willems and A.G. Davis, "Evaluation Techniquesfor ConcreteBuildingEnvelope Components ". RCI Interface, Vol. XX, No. 3, March 2002, 3-15.

72. Davis, A.G., "NDE of Existing Transmission Tower Foundations". Conference on Structural Faults and Repair 2001, London U.K., July 2001.

73. A.G. Davis, "Rapid non-destructive test method at the Taiwan High-Speed Rail project",

Concrete Technology Today, Volume 3, 2004.

74. A. Davis, G. Seegebrecht, and H. Cao, "Concrete Bridge Deck Overlays Evaluated by NDT", Proceeding of ASNT Structural Materials Technology (SMT) Conference -

NDT/NDE for Highways and Bridges, Buffalo, New York, September, 2004.

75. Sansalone, M. and W.B. Streett, 1997, "Impact-Echo: nondestructive evaluation of concrete and masonry," Bullbrier Press, Ithaca, NY.

76. H. Cao, "Implementation of NDT techniques in an underground tunnel investigation",

Proceeding of 6 th International Symposium on NDE in Civil Engineering, St. Louis, Missouri, 2006.

77. E. Dodge, M. Sherman, "Structure evaluation and repair of internally damaged concrete",

Proceedings of Fourth Forensic Congress, Cleveland, Ohio, 2006.

CTLGroup: Nuclear Facility & Nuclear Safety Related Consulting Qualifications The recent Crystal River post-tensioned secondary containment structure incident is a significant concern to the owner-utility, and to the US NRC. The damaged concrete containment wall is 42 inches thick, contains mild reinforcement and un-bonded post tensioning tendons. It is lined with a mechanically-anchored steel liner plate.

During steam generator replacement construction, workers found a planar crack/delamination in the wall, about nine inches from the outer surface. Based on successful experience with services furnished at other Progress Energy plants, CTLGroup was asked to extend its assistance, related to demonstrating nondestructive test methodology-based definition of the extent of the delamination anomaly, as well as supplementary inspection services and testing and characterization of the concrete materials.

RELEVANT PROJECTS AND ACCOMPLISHMENTS CTL has successfully furnished a wide scope of assistance to the nuclear industry, encompassing projects at more than 20 nuclear generating stations nationwide, since 1978.

Additionally, CTLGroup has provided technical services and applied research solutions to EPRI and the US NRC, helping improve the safety, facility management and quality of commercial nuclear facilities. Historic accomplishments related to structural engineering, condition inspection and analysis, facility management consulting, and materials technology in the nuclear power & nuclear safety-related programs are illustrated based on a select project chronology below:

- 1978 - Grand Gulf Nuclear Generating Station's 520-ft tall cooling tower's crane is toppled by high winds while construction nears completion in Mississippi, leaving 100-ft-deep notch; CTL engineers use nondestructive diagnosis and structural analysis to advise contractors how to salvage tower.

• 1979 - Marble Hill Nuclear Generating Station safety and non-safety related structure construction was nearing completion in Indiana. Although the facility never is placed on line since management failures causes the utility, State and Federal regulators to terminate the project, US NRC requires that a comprehensive review of deficient reinforced concrete construction be addressed with a plant-wide concrete NDT and lab testing program, performed at the expense of the construction contractor, by CTL.

- 1979 to 1986 - EPRI Concrete Containment Wall Leakage Research was conducted nationally by several research firms and national laboratories,

including CTL following the TMI accident. It refined the structural design basis for containment wall element design. On the basis of this national engineering research effort, failure criteria and an analysis methodology for predicting concrete containment leakage was developed. CTL's Structural Engineering Laboratory and structural engineering experts conduct a series of complex full scale experiment under ultra high loading, exploring the inelastic behavior under over pressurization and seismic events, of containment walls and large penetrations.

- 1983 - Condition Assessment and Repair of Reactor Bldg Floor Slab, Monticello Nuclear Generation Station in Minnesota is needed when torus ring supplementary support installation reveals presence of severe voids and delaminating in the reinforced concrete base mat. Concrete NDT methods are adopted by CTL to define the complete extent of base mat planar defects, a repair procedure adopting pressure adhesive injection is designed and repairs are conducted. NDT methods are used to verify quality and comprehensiveness of repairs.

- 1991 - Databasing of Long Term Concrete Materials Property Data for Nuclear Generating Stations is performed by CTL to support the US NRC Structural Aging Program, under DOE contract. These data serve as the basis for future plant relicensing decisions.

• 1991 - In-Service Inspection and Structural Integrity Assessment Methods for NPP's - CTL reviewed and assessed nondestructive evaluation, sampling, and structural integrity testing techniques which have application to the evaluation of safety-related concrete components in nuclear power plants, as a component of the US NRC Structural Aging Program.

• 1995 - SELF-MONITORING SURVEILLANCE SYSTEM FOR PRESTRESSING TENDONS - CTL structural engineers/experts in behavior of post tensioning materials demonstrate feasibility of an autonomous prestressing tendon wire break detection system for continuous monitoring of post-tensioned concrete components of nuclear power plants. A one-tenth scale ring model of the Palo Verde nuclear containment structure is used. Strong and recognizable signatures were detected by the accelerometers used. It was concluded that the unbonded prestressing tendons provide an excellent path for transmission of stress waves resulting from wire breaks. Work is conducted under the US NRC SBIR program.

• 1996- Evaluation of Makeup and Blowdown Pipeline Ruptures, Illinois -

Multiple ruptures of the piping system experienced since 1980 resulted in unanticipated, costly emergency-basis repairs at the LaSalle Station. The disruptive nature of these failures prompted a CTL review of feasibility and cost of rehabilitation/replacement options. The objectives of CTL's work were (1) to evaluate theoretical strength and serviceability of the pipeline in its potentially deteriorated state, (2) to identify alternative remedial strategies, (3) to assess

technical feasibility and compare economic factors for available alternatives, and (4) to analyze and present effective rehabilitation methodologies.

• 2000 - Nondestructive Testing, Cook Nuclear Power Plant, Michigan - CTL performed nondestructive impulse radar testing in selected areas to locate horizontal and vertical embedded wall reinforcement.

• 2003 - Onsite Condition Assessment of Concrete, Davis Besse Nuclear Power Station, Ohio - CTL nondestructive inspection experts and concrete technologists evaluated the presence and extent of poor concrete consolidation and internal concrete cracking in concrete walls of the rod refueling area.

- 2004 - Nondestructive Evaluation of Reinforced Concrete Pump Pedestals -

CTL performed nondestructive testing on ten (reinforced concrete pedestal foundations to pumps in the Screen Building at Three Mile Island Nuclear Power Station. Excessive vibrations had been noted. CTL proposed a nondestructive test program comprising a combination of Ultrasonic Pulse Velocity (UPV), Pulseecho ultrasound (UT) and vibrationmeasurements to a) measure the integrity and quality of the concrete in the pedestals, b) evaluate the quality of the sole plate grout and its bond with the concrete substrate, and c) evaluate the mating of the steel top plate with the sole plate.

• 2005 - Nondestructive and Materials Evaluation of Cracking and Leakage Through Reactor Spent Fuel Pool Walls - The spent fuel pool walls are 5-ft thick, stainless steel-lined reinforced concrete. The plant owner has noticed water leakage associated with concrete cracking near the middle of this area. During the site visit, CTL visually and nondestructively examined spent fuel pool wall surfaces to evaluate its current condition for any signs of distress, such as cracking or poor consolidation. Conceptual repair recommendations were made.

- 2007 - Evaluation of 2 Natural Draft Cooling Towers at Byron Nuclear Station, Illinois - Evidence of concrete deterioration and aging in 22 and 24-year old, 495-ft tall cooling towers prompted durability evaluation. Byron incorporates the use of two reinforced concrete hyperbolic natural draft cooling towers for condenser cooling. Exelon retained CTLGroup to assist its staff in evaluating the existing condition of the structure and to provide recommendations for future evaluation and repair needs for the structures.

CONTINUITY OF TECHNICAL EXPERTISE & ADDITIONAL RESOURCES To augment project teams such as the one that is presently active at the Crystal River site, CTLGroup's key senior staff and management have historically sustained continuity of technical and project management expertise and innovation, contact with the power industry decision makers, and led professional development efforts needed to provide timely solutions associated with nuclear safety and facility management issues.

For example, CTLGroup Senior Principal Structural Engineer R.G. Oesterle, S.E.

who led the EPRI containment wall integrity research referenced in this document, is Chairman of the ASME/ACI Reactor Vessel Committee's Subgroup on Design Task Group on Shear, and a nationally recognized structural engineer expert in diagnosis and repair of structural failures.

Additionally, CTLGroup Senior Principal Engineer Adrian Ciolko, P.E. served the nuclear power utilities and regulatory agency at the Marble Hill, Monticello, Byron, US NRC Tendon Surveillance System and LaSalle projects referenced above, and is presently project manager for an EPRI project entitled, Concrete Aging Reference Manual for Long Term Operation. In this project, a review of degradation mechanisms has been conducted. Likely locations in plants have been identified. Individual structures and subcomponents will be prioritized based on degradation mechanisms and consequence and probability of failure. The scope of this analysis will include safety related structures, such as containments, spent fuel storage, auxiliary buildings and radwaste buildings, as well as balance of plant structures such as cooling towers, intake structures, intake canals, circulating cooling water lines, turbine pedestals and other key exterior structures, looking ahead the next plant relicensing interval.

When CTL is using IR and IE, can they determine relative concrete quality of locations tested as part of CTL NDE procedure?

In general, the Impulse Response (IR) test results is influenced by concrete quality and existence of defects at the test point. The aspects in concrete influencing IR results include presence of delamination, cracking, significant void or honeycomb and change in concrete properties. The most significant factor is the presence of delamination which effectively reduces the thickness of wall or slab responding to the impact. Considerable difference in quality of concrete is typically reflected in the test results. For example, a core removed from panel RBCN-0014-N (Core #13) where a higher mobility value was obtained by NDT, had less coarse aggregate in the concrete, which changed density and modulus in that localized area, no delamination was noted in these areas with subsequent boroscope examinations.

Discuss the planned NDE method, its reliability, industry experience and other pertinent information, B) discuss supplementary verification plans to ensure results are reliable.

A) Impulse Response (IR) test was chosen as the primary NDT technique to evaluate the extent of delamination. The IR method uses a low strain impact from a hammer equipped with a load cell to send a stress wave through the element under test. The response to the input stress is measured using a velocity transducer (geophone). Both the hammer and the geophone are linked to a portable field computer for data acquisition and storage. Time records for both the hammer force and the geophone velocity response are transformed into the frequency domain using the Fast Fourier Transform (FFT) algorithm.

Average Mobility is the key parameter that the dynamic IR test produces. It is defined as the structural surface velocity responding to the impact divided by the force input [(m/s)/N]. The mean mobility value over the 0.1-1 kHz range is directly related to the modulus, density and the effective thickness of the element. In general, presence of significant voiding or an internally delaminated or un-bonded layer will result in an increased average mobility value. On the other hand, a sound concrete element without distress will produce a relatively low average mobility value. The test results can be analyzed and presented in the form of contour plots. The suspect areas can be identified through a scaled color scheme.

Comparing to another well-known NDT method Impact-Echo (IE) test, the IR test uses a compressive stress impact approximately 100 times that of the IE test. This greater stress input means that the plate responds to the IR hammer impact in a bending mode over a very much lower frequency range (0-1 kHz for plate structures), as opposed to the reflective mode of the IE test which normally requires a frequency range of approximately 5 to 30 kHz, The influence of reinforcement and tendons in the structure has generally less impact than it would for IE test, while delamination at relatively shallow depth, if any, will dominate the signal response in IR testing. It makes it ideal to evaluate the presence of delamination without having to layout locations of tendon and reinforcing bars prior to the testing in a time critical project. However, the IR test cannot detect with high certainty the absolute depth of delamination; rather it's on a comparative basis. The width or size of crack cannot be determined in the IR testing.

The IR test method has been used to evaluate concrete structure condition in the past 20 years.

The test method is in the process of being standardized by ASTM. CTLGroup has extensive experiences in utilizing this method to characterize defects in concrete. IR test has been used in evaluating concrete structures in both nuclear and fossil power plants. CTL Group experience for nuclear related structures has been compiled (see attached).

B) According to the Progress Energy procedure PT-407T, Rev. 2, concrete core samples are removed in areas with high mobility values (greater than 1.0) to confirm the presence of delamination. Core samples are also removed in areas where mobility value is in the "Gray" (between 0.4 and 1.0) range to verify the condition, unless the slightly elevated values can be dispositioned through evaluation. Many cores have been removed based on the IR test results along the boundary of delamination in the section where steam generator opening is located. At this time, the approximate 20 cores so far removed indicated the IR results have been accurate in characterizing the extent of delamination in the steam generator opening area. Also according to the test procedure, a population of core samples is also removed from areas where low mobility values (less than 0.4) are obtained to confirm the sound concrete condition. Based on the core samples removed, the IR results have been accurate to detect a delamination in the concrete.

- .~ \.

C&TGROUP Building K ege. Deloverg Resultsm. www.CTLGroup.com November 13, 2009 Via e-mail: paul.e.fa-qan(,pqnmail.com Mr. Paul Fagan Tech Services Support Progress Energy Corp.

15760 West Powerline Rd.

Crystal River, FL 34428-6708 Crystal River Nuclear Plant: Engineering Consulting Related to Delaminations in the Primary Containment Concrete Wall, CR3 - Qualifications Statement CTLGroup Project No. 059169

Dear Mr. Fagan:

As you requested, CTLGroup has prepared nondestructive testing (NDT) qualification information for each member of our NDT team involved in the testing at the Crystal River Nuclear Power Plant, Florida.

Honggang Cao, CTLGroup Senior Engineer, is the NDT expert and a team leader for ground penetrating radar (GPR), impulse response (IR), and impact echo (IE). He has extensive knowledge and experience in various NDT methods for testing and evaluation of civil engineering structures. He is a voting member of the American Concrete Institute (ACI)

Committee 228, Nondestructive Testing of Concrete in Structures. He published 13 technical articles on nondestructive testing and evaluation.

Additional members of the CTLGroup NDT team are as follows:

• Team Leaders for GPR, IR, and IE:

o Salvador (Sal) Villalobos-Chapa, Associate II in Structural Evaluation Group o Jerry Harano, Senior Technical Specialist in Structural Evaluation Group o Muamer (Mike) Klaric, Technician in Structural Evaluation Group o Dean Adams, Technician in Structural Evaluation Group (GPR only)

• Team Support:

o Dean Adams, Technician in Structural Evaluation Group (also GPR Team Leader) o Michael Bonner, Associate I in Structural Evaluation Group

" Julia Johnson, Associate I in Materials Testing Group All NDT team members have undergone training in applications of different NDT techniques.

The training was lead by personnel experienced in NDT evaluation. The training took place either at the CTLGroup laboratory or in the field on specific projects. In addition, some of the team members received training from the NDT equipment manufacturers and some took Corporate Office: 5400 Old Orchard Road Skokie, Illinois 60077-1030 Phone: 847-965-7500 Fax: 847-965-6541 Washington D.C. Office: 9030 Red Branch Road, Suite 110 Columbia. Maryland 21045-2003 Phone: 410-997-0400 Fax: 410-997-8480 CTLGroup is a registered d/b/a of Construction Technology Laboratories, Inc.

Mr. Paul Fagan, Progress Energy Corp. Page 2 of 2 Crystal River Nuclear Plant November 13, 2009 CTLGroup Project No. 059169 academic level courses related to NDT. Information on the types of NDT training of our staff is provided in the attached CTLGroup Performance Based Training Records. These records were prepared specifically for the Crystal River Power Plant project. In addition to the training records, updated resumes for all NDT team members are also provided.

We appreciate the opportunity to work with you on this project. Should you have any questions concerning qualifications of our NDT team or this project please contact us at (847) 972-3150.

Very truly yours, 4

Jerzy Z. Zemajtis, Ph.D.

Senior Engineer1 and Project Manager izemaitis(@ctlqroup.com Tel. (847) 972-3150 Attachments 1 Registered Professional Engineer in Washington, British Columbia, Manitoba and Ontario

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Does the PGN Testing Procedure identify how CTL calibrates their equipment, qualification of personnel, and equipment set-up (i.e., frequencies)?

This question pertains to PGN procedure PT-407T, Reactor Building Concrete Examination and Testing, Revision 2.

The question is split into three areas with specific procedure steps stated to address each area.

Area 1 - Calibration Step 3.2 Responsibilities Step 3.2.1 The Condition Assessment Consultant is responsible for:

Provide equipment list and associatedcalibrationdocumentation Step 3.3 Limits & Precautions Step 3.3.2 The equipment utilized to perform the NDT was calibratedin the field during trial use by CTLGroup. This method of validating the test process and equipment for a specific application is standardpractice for concrete condition assessments utilizing NDT.

Step 5.3 Reports Step 5.3.1 An equipment list with calibrationdocumentation will be provided for the NDT used. The NDT process calibration/validationdocument will be included in the report.

For a criticalstructure of this scale, more correlationdata is desired in order to finalize a more comprehensive calibration.

Individual equipment packages have been established to track specific calibrated equipment in order to link individual NDT locations with a calibrated equipment package.

The Exterior Containment Inspection Log requires an Equipment Package Number to be recorded for each NDT location. The Equipment Package Number is traceable to a permanent plant record documenting the calibration records for the equipment.

Area 2 - Qualification Step 3.2 Responsibilities Step 3.2.1 Page 1 of 2

The ConditionAssessment Consultant,CTLGroup, shall be responsible for assuringthat all individuals under his supervision are properly trainedin the use of this procedureand associatedequipment.

Step 3.2.1 The Condition Assessment Consultant is responsible for:

Provide personnelqualification records for lead Engineer Step 3.5.2 Initial Conditions ENSURE that all personnel are familiarwith the operatingmanuals of the equipment to be used during the inspection.

Step 5.3 Reports Step 5.3.1 The report will include personnelqualification records of lead engineers who performed the NDT.

Area 3 - Equipment set-up Step 3.2 Responsibilities Step 3.2.1 The Condition Assessment Consultant is responsible for:

Provide calibration/validationdocumentation to substantiate the NDT methods to be used and to support the dedicationof the software (SMASH) being used to evaluate the NDT data.

Step 3.3 Limits & Precautions Step 3.3.2 The equipment utilized to perform the NDT was calibratedin the field during trialuse by CTLGroup. This method of validating the test process and equipment for a specific application is standardpractice for concrete condition assessments utilizing NDT. , page 1 TURN ON the computer to start setup process.

Enclosure 6, page 1 TURN ON the computer to start setup process.

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