ML102871110
| ML102871110 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 02/23/2010 |
| From: | - No Known Affiliation |
| To: | Office of Information Services |
| References | |
| FOIA/PA-2010-0116 | |
| Download: ML102871110 (71) | |
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{{#Wiki_filter:A 6.3 Thermal Effects of Greasing I
Description:
The high-strength steel wires that make up the pre-stressing tendons are very sensitive to stress corrosion cracking while under tension. Corrosion protection was initially done by grouting the inside of the tendon sleeves after tendon original stressing. However, NRC Reg1.107 (FM 6.3 Exhibit 1 is NRC RegGuide 1.107 Rev.1 from February 1977) and NRC Reg1.90 (FM 6.3 Exhibit 2 is NRC RegGuide 1.90 Rev. 1 from August 1977) moved the industry towards non-grouted tendons in order to fulfil in-service periodic inspections (FM 6.3 Exhibit 3 is a 1982 published paper by H. Ashar and D.J. Naus on the topic). From that time on, grease has been used for corrosion inhibition of the stressed tendons. The procedure to grease the tendon during original installation is described in FM 6.3 Exhibit 4 (part of the documentation generated after the dome delamination event in 1976) and observed in the examples of FM 6.3 Exhibit 5 (typical pre-stressing field documentation including details of the greasing operation):
- 1. Install the tendons inside the sleeves (the sleeves themselves were installed as part of the concrete form-work and they are embedded in the concrete);
- 2. Tension the tendons to lock-off force (the details of the tensioning procedure are investigated in other failure modes);
- 3. Grease the tendons (basically done by filling the sleeves with grease, all around the tendons themselves);
The grease is injected in the tendon sleeves at a pressure up to 85psi and a temperature around 160oF (FM 6.3 Exhibit 4). The pressure and temperature cause thermal expansion of the duct and of the concrete surrounding the duct. Differences in expansion and/or rate of expansion can induce thermal stresses and possibly cause cracking. Additionally, the tendons are greased again during surveillance activities after they have been tested (FM 6.3 Exhibit 15). 2/23/10 G"
. f. .- i... Page 1 of 4 craf...t.1 L Ur...... ..
Data to be collected and Analyzed:
- 1. Details of the original greasing procedure (FM 6.3 Exhibit 4 and FM 6.3 Exhibit 5);
- 2. Materials properties comparison (FM 6.3 Exhibit 6 is pp. 88-89 of P.K. Mehta reference book on concrete "Concrete: Structure, Properties, and Materials" and FM 6.3 Exhibit 7 is the summary of Coefficient of Thermal Expansion (CTE) values and FM 6.3 Exhibit 8 is a summary of Thermal Conductivity values);
- 3. Calculate the heat transferred from the grease to the sleeve during tendon greasing (FM 6.3 Exhibit 9 is a thermal transfer analysis done by P11);
- 4. Calculate pressure capability of the tendon sleeves (FM 6.3 Exhibit 10 is a sleeve pipe pressure calculation done by Progress energy);
- 5. Calculate additional stress created by the grease injection at high temperature and pressure using first principles (FM 6.3 Exhibit 12 is a P11 calculation of the stresses generated by the hot grease);
- 6. Investigate grease additions during surveillance activities (FM 6.3 Exhibit 15);
Discussion: The files exampled in FM 6.3 Exhibit 5 are from the original installation of the post-tensioning tendons. They are the "Crystal River 3 Reactor Building Pre-Stressing System Tendon History" files. The identification number is the number of the tendon in question. The first example in FM 6.3 Exhibit 5 is tendon 12V2:
- 1. Tendon 12V2 is the second (2) Vertical tendon (V) between buttresses 1 and 2 (12), hence 12V2;
- 2. The tendon was received on-site on 1/16/1974;
- 3. And installed in the conduit (sleeve) on 7/3/1974; 2/23/10 Page 2 of 4 Draft 1 _ t "ion
- 4. No wires were removed or replaced;
- 5. The field anchor-head was button-headed on 8/27/1974;
- 6. And subsequently stressed on 10/14/1974;
- 7. All the elongation is on the same side as the vertical tendons are accessible only on the dome side for tensioning;
- 8. The total elongation is 12.5". This is the elongation from 1,500 psi (FM 6.3 Exhibit 5) or "an initial force that will remove all slack" (FM 6.3 Exhibit 13 chapter 1.0 Purpose), which was taken as 360 kips in practice (FM 6.3 Exhibit 13 chapter 3.0 Design Inputs).
The theoretical elongation of 14.94 inches (FM 6.3 Exhibit 14) is longer than the actual elongation because of the wobble friction in the wires (FM 6.3 Exhibit 13);
- 9. The grease is then filled on 10/23/1974; 10.At a pressure of 112 psi and a temperature of 126 0 F; An important point to remember is that the issue of differential thermal expansion in this case is NOT associated with different Coefficient of Thermal Expansions (CTE) between the two materials but with different Thermal Conductivity Coefficients between the steel sleeve and the concrete. The sleeve expands much faster initially and this creates a load on the slowly heating and expanding surrounding concrete (see FM 6.3 Exhibit 4 from the dome analysis).
We made the conservative assumption that all the heat~from the grease was transferred to the sleeve rather than using the study on heat transferred from the grease to the tendon sleeve (FM 6.3 Exhibit 9). From observation of the tendon surveillance data, the number of greasing cycles is under 4 for all tendons, and it is 1 for most tendons in the structure. Note that an analysis of potential tensile strength degradation due to thermal effects is included in FM 4.8. 2/23/10 Draft 1e -' , Page 3 of 4
Verified Supporting Evidence:
- a. The Thermal Conductivity Coefficient of the steel and concrete are very different so that the sleeve expands much faster than the concrete and this creates a force from the hot sleeve to the still-cold surrounding concrete (concrete 1 btu/ft/h/°F and steel 25 btu/ft/h/°F from FM 6.3 Exhibit 8);
Verified Refuting Evidence:
- a. Once the temperature has equilibrated at the sleeve/concrete interface, there is no thermal stress because the coefficient of thermal expansion of the sleeve steel material and of the concrete are very similar (FM 6.3 Exhibit 6);
- b. The pressure capability of the tendon sleeves is high enough to support the 85 psi grease injection pressure (FM 6.3 Exhibit 10);
- c. Stress analysis demonstrates that the additional stresses added due to thermal effects of greasing in the concrete do not exceed the concrete tensile capability (FM 6.3 Exhibit 12);
== Conclusion:==
The stresses due to high-temperature greasing did not lead to the delamination. They may have contributed to localized micro-cracking around the tendon sleeves. 2/23/10 PH1Przprieta F~rif"ft'd 7 )p4-27fl--2 Page 4 of 4 Draft1
Revision I FM 6.3 Exhibit 1 page 1 of 7 U.S. NUCLEAR REGULATORY COMMISSION Rev1ion7
'REGULATORYGUIDE 47OFFICE OF STANDARDS DEVELOPMENT REGULATORY GUIDE 1.107 QUALIFICATIONS FOR CEMENT GROUTING FOR PRESTRESSING TENDONS' IN -CONTAINMENT STRUCTURES A. INTRODUCTION B. DISCUSSION General Design Criterion 1. "Quality Standards The recommend&,tions of this guide are applieable and Records." of Appendix A, "Gencral Design when portland cement grout is used as the corrosion a-Criteria for Nuclear Power Plants," to 10 CFR Part inhibitor for the highly stressed tendons of prestres-50, "'Licensing of Production and Utilization sed concrete containment structures. The rcommen-Facilities," require that structures, systems, and dations of the guide are not intended for use in rela-components important to safety be designed, tion to the grout for foundation anchors.
fabricated, and erected to quality standards commen. surate with the.importance of the safety functions to To date, the staff has evaluated applications be perf6rmed. proposing grout as the corrosion protection system for both bar tendons and strand tendons. The recom-The prestessing tendon system of a prestressed con. mendations of this regulatory guide therefore apply crete containment structure is a principal strength to a grouted tendon system when the tendon is element of the structure. Since the ability of the con- fabricated from either bars or strands. For grouting tainment structure to withstand the events postulated of wire tendons, a program based on similar quality to occur during the life of the smtcture depends on standards may be developed and submitted to the 1. the functional reliability of the structure's principal staff for evaluation. strength elements, any signiicant deterioration of the prestressed elements due to corrosion may present Unlike greased tendons, pouted tendons are not Totential risk to the public safety. Hence it is impor.. available for direct inspection after they an grouted. tent that any system for inhibiting corrosion of the It is therefore essential that the proposed grout and prestressing elements possess a high degree of grouting procedure be thoroughly evaluated before it reliability in performing its intended function. is used in the construction of the containment struc-ture. An advantage of grouting, in addition to This guide describes quality standards acceptable providing corrosion protection. is that a well-to the NRC staff for the use of portland cement grout designed and well-constructed grouted tendon system as the corrosion inhibitor for prestressing tendons in provides a degre of bond between the tendons end 1 prestressed concrete containment structures. The Ad- the surrounding concrete. This bond in turn helps the visory Committee on Reactor Safeguards has. been anchorage system to resist the fluctuating stresses consulted concerning this guide and has concurred in that arise after construction of the structur. the regulatory position.
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FM 6.3 Exhibit 1 page2 of7 ...... physical and -chemical properties of grout. The limits recommended for chlorides, nitrates, Regulatory Position C.I of this guide briefly sulfates, and sulfides in Regulatory Position C.I.e describes minimum quality standards for grout should not be exceeded in the overall composition of materials, referencing the ASME Code Articles the grout. The quantities of these substances in the where applicable and acceptable to the NRC staff. grout constituents should be determined individually The regulatory position also outlines important con- for each of the constituents by the applicable ASTM siderations affecting proper grouting. References 2,3. (American Society of Testing and Materials)' and 4, as well as data furnished by applicants who methods and expressed in parts per million parts of have proposed grout as the corrosion inhibitor for water in the grout composition. prestressing steel, have been used to arrive at this position. In general, portland cement conforming to ASTM CISO Type I or Type IL is suitable for the grout. Appendix A to this guide provides a list of relevant However, grouting under certain climatic or en-literature that may be used by the applicant to es- vironmental conditions may dictate the use of other tablish procedures and criteria for the specific types of cements. Chlorides are normally present in grouted tendon program. However, the listing of cement, but the amount is usually not reported. The these references does not constitute a blanket en- determination of chlorides in cement should be a re-dorsement by the staff of their content. quirement when specifying the cement for grout. Specific areas of concern that should be given proper attention during the development of a grouted Admixtures should be free of any substance likely tendon system are discussed 4n the following to damage the prestressing steel. Use of aluminum paragraphs. powder to produce expansion has been viewed by many engineers as having possible deleterious effects. The effectiveness of grout in performing its in- Under an alkaline environment (pH >9), the tended function of inhibiting corrosion depends aluminum powder generates minute bubbles of mainly on two characteristics: hydrogen gas (Hj)that would not endanger the ten-sioned steel at the prevailing range of pressures and I. The grout (whether freshly mixed or hardened) should not cause chemical attack on the prestressing temperatures. However, the potential danger of hydrogen attack on steel does exist if the tensioned' elements through its interaction with the material of steel elements or stressed anchorage components con-the tendon steel, the material of the anchor hardware, tain surface flaws. The parameter affecting the use of or the material of the duct.: aluminum powder are described in Reference 9.
- 2. The grout should completely fill the tendon duct on hardening. The protective mechanism of grout is primarily dependent on its ability to provide a continuous Various deleterious substances have been reported alkaline environment around the tensioned steel ele-as potential sources of corrosion of prestressing steel. ments. The natural alkalinity of the primary product Most of the reported failures of prestressing elements of cement hydration (i.e., calcium hydroxide) tends to have been attributed (a) to the presence of chlorides be at a pH value of 12.5. The effectiveness of the in the atmosphere or in the constituents of grout or alkaline environment may be reduced by the leaching (b) to the presence of hydrogen sulfide in the at- of alkaline substances with water, by reaction in an mosphere (Refs. 5, 6. and 7). Nitrates and sulfates acidic or sulfide-containing environment, or by the generally found in mixing water have been theorized presence of oxygen and chloride ions. It is reported in to be potential sources of stress corrosion of Reference 10 that the ability of chloride ions to prestressing steel. However, it has been reported develop corrosion increases with decreasing (Ref. 8)'that. in a concrete environment, oxygenated. alkalinity of the calcium hydroxide solutions. Thus it anions such as sulfates and nitrates do not exhibit in- is advisable to monitor the pH value of'the in-place tense corrosion properties. It has also been reported grout under actual field conditions and ensure that it (Ref. 3) that most of the chlorides are neutralized remains above a value where the passivating effect of during the hydration of portland cement. The the grout is not reduced by the available chloride ions threshold values below which these substances will in the composition of the grout.
not participate in initiating corrosion have not been established. Henc a safe and prudent approach Section CC-22432 of the ASME Code (Ref. 1) re-would be to make sure that these substances are quires the use of flow cones with the limits on efflux limited to the lowest practical levels in grout con. times at the specific quiescent times to ensure ade-stituents. The use of water contaminated with quate fluidity of the grout. However, for certain types I hydrogen sulfide should. be prohibited. of grouts (in particular, one with a thixotropic ad-ditive), these requirements may not be appropriate to "For the purposes of this guide. a "duct" is a hole or void define their pumpability. Applicants in such cases provided in the conetes for the post.tensioning tendon. A duct may be provided by emaedding meai .heahinI in cat-in-place 3A lin of rlmivn ASTM standards b provided in Appendix B of concrete. this gide. 1.107-2
FM 6.3 Exhibit 1 page 3 of 7 should propose alternative means of quality control 1. Materials to accomplish the same objective. Also, a general practice is to limitthe pumping presur during a. Portland Cemenet.'Cement should conform to grouting to 300 psi (set Refa. 2 and 3). However, the requirements of ASTM C150. The type to be I, grout with a thixotropic additive may need higher selected should be suitable for the intended use. pumping pressures for long vertical tendons. In such cases. it should be demonstrated through tests that b. Fbu Aggeqate. Fine aggregate-filler may be high pressures will not deteriorate the quality of used when permitted by the requirements of Article grout; damage the duct, duct splices, or surrounding CC-2243.1 of the ASME Boiler and Pressure Vessel concrete; or deform the containment line. Code. Section I1i, Division 2 (Ref. 1). In addition to the control on grout materials and on mixing and injecting the grout to ensure the in- c. Water. The water should not contain In-tended protection of the prestressing steel, it is impor. gredients harmful to the prestressing steel or the tant to take other precautions directly related to the grout. Water contaminated (I ppm) with hydrogen corrosion protection of the prestressing steel: sulfide (sulfide ion) should be prohibited. The water to be used for grouting should be qualified for use by
- 1. It is necssay that the tendon remain clean, dry, making comparative tests in accordance with the test free from deleterious corrosion, and undamaged up methods and tolerance levels described in Article CC-to the time it is grouted. Specific protection measures 222.3.2 of the ASME Code.
should be provided at coastal sites, at sites having a high moisture level, and at sites near industrial areas. d. AdmUteu . Acceptable admixtmures may be used if tests have demonstrated that their use
- 2. When a preassembied tendon-sheathing as-sembly is to be placed before concreting, the tendon improves the properties of grout, -e.g., increases should be protected against corrosive environment during assembly, handling, storing. transporting, workability, reduces bleeding, prevents water separa-tion when pumped at high pressure, entrains air, ex-pands the grout, or reduces shrinkage. The quantities I
placing, and tensioning. of harmful substances in the admixture should be
- 3. Before placing the tendon in the duct, it is im- kept to a minimum. Use of calcium chloride should portant to ascruin that the duct is free of obstuc- be prohibited.
tions, moisture, and other deleterious substances.
- r. limits on Deleterious Substsns and pH.
- 4. Ferrous metal sheathing is galvanized to protect it against corrosion before grouting of the tendon. (i) The quantity of the following substances However, the contact surfaces of the tendons and the (added Individually for each constituent and expres-sheathing are potential areas for the formation of sed as parts per million parts of water) in the overall corrosion cells and hydrogen evolution. From the grout composition should not exceed the following tendon corrosion point of view, this is critical if the limits:
time between the tensioning and grouting is long and the duct contains moisture with or without Chloride 100 ppm deleterious substances. (200 ppm if pH is maintained above 12)
- 5. In general, the period between tensioning and grouting is critical from the standpoint of stress cor- Nitrates 100 ppm rosion or hydrogen strs cracking. Steps should be taken to minimize this time period. Sulfate 250 ppm Effective corrosion protection of prestressing Sulfides 2 ppm (test method of Ref. 15) tendons can be provided by portland cement grout if appropriate precautions are taken to eliminate the potential sources of corrosion. To this end, close (2) The pH value of th grout at inlet and outlet quality control is necessary for each constituent of the grout, the tendon material, and the tendon duct of the duct should be maintained above 11.6 (12 if the allowable chloride content is 200 ppm). I material and for the method of mixing and pumping the grout and ensuring that the tendon is surrounded (3) During the gpouting period, the amount of from end to end with qualified pout. deleterious substances in the grout constituents should be checked weekly and whenever the composi-C. REGULATORY POSITIoN tion of the constituents is changed or is suspece of The following minimum quality standards should having changed.
be maintained when portland cement grout is to be
- SuIwam in ft form of sulfur *wmid =a omponent used for the corrosion protection of prestressing steel. ned not be eonsidcr=
1.107-3
FM 6.3 Exhibit 1 page 4 of 7
- 2. Physical Properties of the Grout should be protected from inclement weather and other adverse environmental conditions during this The physical properties of the cement grout should period. If an additional delay is expected, the tendons satisfy the requirements of Article CC.2243.2 of the should be protected by methods or productfithat ASME Code. Adequate tests should be carried out in would not jeopardize the effectiveness of the grout as accordance with the test methods described in that a corrosion inhibitor. In any case, the tendoil' article to demonstrate that the grout satisfies these re- anchorages should be visually examined just prior to quirements. gpouting to detect any. breakage or degradation of prestressing elements as evidenced by the movement
- 3. Duct or dislocation of anchoring hardware.
- a. The duct size should be adequate to allow the insertion and tensioning of tendons without undue b. Fltshing before grouting is not recommended.
difficulty. The area of the grout that penetrates and When flushing has to precede the grouting, ap-surrounds the tendon at any section should be at least propriate measures should be taken to ensure that: equal to the cross-sectional area of the tendon. The duct sheathing and its splices should be of ferrous (1) The level of harmful substances in the in-metal and should be protected to prevent corrosive place grout does not increase above that in the deterioration prior to the grouting of tendons. The designed grout. and duct sheathing and its splices should be sufficiently tight that a thin cement slurry cannot pass through (2) The properties of the injected grout satisfy while the surrounding concrete is being placed. The the recommendations in Regulatory Position C.2. duct sheathing and its splices, when surrounded by hardened concrete, should be capable of c. Tests should establish the length of time that the withstanding the maximum grouting pressure grout can be used after mixing. The tests should without leakage. verify that:
*b. Vents should be provided at any major changes (1) The intended reaction of such admixtures as in section of the duct, as well as at the high points. expansive agents continues when such a grout is in-Drains should be provided at the low points. Vents jected in the duct, and and drains should be checked for possible- obstruc-
- i. tions prior to grouting. (2) This time is less than that required for the in-itial set of the grout as determined by the method of
- 4. Equipment for Grouting ASTM C191.
- a. The gpouting equipment should include a mixer that is capable of continuous mechanical mixing and d. The temperature along the entire length of the I that can produce a grout free of lumps and un- tendon duct duinng grouting should be above 359F.
dispersed cement. To this end, tests should be per- This temperature should be maintained until the formed to demonstrate the optimum range of mixing minimum (2-inch cube) strength of the job-cured time and the sequence of placing the constituent grout exceeds 800 psi. The grout temperature should materials in the mixer under extreme anticipated en- not exceed 900F during mixing and pumping unless it vironmental conditions. can be established by test that a higher temperature will not adversely affect the grouting operation.
- b. The pump should be of the positive displace-ment type and should be capable of exerting the re- e. The. development of the grouting procedure quired maximum pressure. A safety device should be should consider the extremes of anticipated en-provided to guard against exerting a pressure that vironmental conditions. The procedure should ensure could damage the duct, duct splices, or surrounding that the ducts will be filled and that the tendon steel concrete or deform the containment liner. The pumps will be completely surrounded by grout.
should not suck air in with the grout.
- f. Aliaopenings, air vents, and drains should be
- c. A screen having clear openings not more than hermetically sealed after prouting to prevent the in-1/1 inch (1/4 inch for grout with a thixotropic ad- gress of water and other corrosive agents.
ditive) should be provided between the mixed grout and the pump to ensure that the grout does not con- g. If an applicant chooses to provide permanent tain lumps. If an excessive amount of lumps remain protection of the anchor hardware by means of on the scren, the batch should be rejected. qualified grout or concrete, the protection should be provided on the following bases:
- 5. Grouting
- a. Grouting should be carried out immediately (1) Ali exposed anchor hardware should be after tensioning. The period between tensioning and thoroughly examined before being provided with the grouting should be kept below 72 hours. The tendon .permanent protection.
1.107-4
FM 6.3 Exhibit 1 page 5 of 7 Except in those cases in which the applicant
.1
'I (2) The permanent protection should be designed and constructed in a manner that would prevent the intrusion of water and deleterious sub-stances to the anchorage components.. proposes an acceptable alternative method for com-plying with specif*ed portions of the Commission's regulations. the guide will be used by the NRC staff on the following bases:
- 6. Tendon The tendon should be clean, dry, 'free from deleterious corrosion, and undamaged up to the time 1. Submittals in connecion with construction per-when it is grouted. The pressembled tendon mit applications docketed after February 14. 1977.
sheathing assembly should be protected against cor- will be evaluated on the basis of this guide. rosive influences from the time of assembly to the time of grouting.
- 2. Submittals in connection with operating license D. IMPLEMENTATION applications for plants whose construction permit ap-The purpose or this section is to provide informa- plications were docketed prior to February 14. 1977.
tion to applicants and licenses regarding the NRC will be evaluated in accordance with the commitment staff's plans for using this regulatory guide. made by the applicant in the construction permit. 2 1.107-5
FM 6.3 Exhibit 1 page 6 of 7 APPENDIX A FtEFERENO!S
- 1. "Code for Concrete Reactor Vessels and Con- Aug. 1965. Copies may be obtained from the tainments," American Concrete Institute Committee American Water Works Association, 2 Park Avenue, 359 and American Society of Mechanical Engineers New York, N.Y. 10016.
Subcommittee on Nuclear Power, 1975. Copies may be obtained from the American Society of 9. "Admixtures for Concrete," American Mechanical Engineers, 345 E. 47th St., New York, Concrete Instituts Committee 212. Copies may be N.Y. 10017 or from the American Concrete Institute, obtained from the American Concrete Institute. P.O. P.O. Box 19150. Redford Station, Detroit, Mich. Box 19150, Redford Station. Detroit, Mich. 48219. 48219.
- 10. Hausman, D. A., "Steel Corrosion in
- 2. "Recommended Practice for Grouting of Post. Concrete," Materlb Protection. November 1967.
Tensioned Concrete," Prestressed Concrete Institute Copies may be obtained from the National Associa-Committee on Post-Tensioning. published in PCI tion of Corrosion Engineers, 2400 West Loop S., Journal. Nov./Dec. 1972. Copies may be obtained Houston, Texas 77027. from the Prestressed Concrete Institute, 20 North Wacker Drive, Chicago, IlL. 60606. 11. Hartead, 0. A,, et aL "Testing for Large Curved Prestessing Tendons," Proceedings of the
- 3. "Report on Grout and Grouting of Prestressed American Society of Civil Engineemr Power Division.
Concrete," Proceedings of the Seventh Congress of March 1971. Copies may be obtained from the the Federation Internationale di la Precontraints. American Society of Civil Engineers, 345 E. 47th 1974. Copies may be obtained from the Federation Street, New York, N.Y. 10017. Internationale do ta Precontrainte, Terminal House., Grosvenor Gardens. London SWIW OAU. 12. Lange, H-, "The Vacuum Process, A New Method for Injecting Prestressing Tendons," paper
- 4. "Specifications for Structural Concrete for submitted for the Seventh Congress or the Federation Buildings." American Concrete Institute Committee Internationale de Ia Precontrainte, New York, N.Y.
301. 1972. Copies may be obtained from the 1974. Copies may be obtained from the Federation American Concrete Institute` P.O. Box 19150, Red- Internationale do Is Precontrainte, Terminal House. ford Station. Detroit. Mich. 48219. Grosvenor Gardens. London SWIW OAU. S. Leonhardt F.. PrutressedConcrete Design and 13. Schupack, M., "Development of a Water Retentive Grouting Aid to Control the Bleed in Ce-Constinction. Wilhelm Ernst & Sohn, Berlin, Second ment Grout Used for Post-Tensioning," presented at Edition. 1964. the Seventh Congress of the Federation Inter-nationale de Is Precontrainte, New York, N.Y., 1974.
- 6. Szilard, RL "Corrosion and Corrosion Protec- Copies may be obtained from the address shown in tion of Tendons in Prestressed Concrete Bridges," Reference 12.
ACI Journal, Jan. 1969. Copies may be obtained from the American Concrete Institute, P.O. Box 14. Kajfasz, S.. at al, "Phenomena Associated with 19150, Redford Station, Detroit, Mich. 48219. Grouting of Large Tendon Ducts and Morphology of Defects," technical contribution to the Seventh
- 7. Monfore, G. E., and Verbeck, G. J, "Corrosion Congress of the Federation Internationale de la of Prestressed Wire in Concrete," ACI Journal, July Precontrainte, New York, N.Y. 1974. Copies may be 1960. Copies may be obtained from the address obtained from the address shown in Reference 12.
shown in Reference 6.
- 15. "Standard Method for the Examination of
- 8. Scott. G. N., "Corrosion Protection Properties Water and Waste Wata"-1971. Copies may be ob-of Portland Cement Concrete," Journal of the tained from American Public Health Association, American Water Works Association, Vol. 57, No. 8, 1015 18th Street NW., Washington, D.C. 20036.
,\
1.107-6
-FM 6.3 Exhibit 1 page 7 of 7 APPENDIX B LIST OF RELEVANT ASYM STANDARDS
'I C109-73, "Standard Method of Test for Compressive C494-71, "Standard Specification for Chemical Ad. Strength of Hydraulic Cement Mortars (Using mixtures for Concret" 2-in. Cube Specimens)" D512-67. "Test for Chloride Ion in Industrial Water C1S0-74, "Standard Specification for Portland Ce- and Industrial Waste Watee" ment Concrete" D992-71. "Test for Nitrate Ion in Water" C191-74, "Standard Method of Test for Tune of Set- D516-74, "Tests for Sulfate Ion in Water" ting Hydraulic Cement by Vicat Needle" D596-74. "Pepordng Results of Analysis of Wate"" C260-74, "Standard Specifications for Air- D! 129-74. "Terms Relating to Water" Entraining Admixtures for Concrete" D1293-65. "pH of Water and Waste Water" 1.107-7
FM 6.3 Exhibit 2 page 1 of 12 Revision 1I U.S. NUCLEAR REGULATORY COMMISSION August 1977 REGULATORY GUIDE OFFICE OF STANDARDS DEVELOPMENT REGULATORY GUIDE 1.90 INSERVICE INSPECTION OF PRESTRESSED CONCRETE CONTAINMENT STRUCTURES WITH GROUTED TENDONSt A. INTRODUCTION deleterious environment, (3) the extent of temperature variations, and (4) the quality of the General Design Criterion 53, "Provisions for Con-. grout and its installation. Following the recommen-tainment Testing and. Inspection," of Appendix A, dations of Regulatory Guide .1.107, "Qualifications "General Design Criteria for Nuclear Power Plants," for Cement Grouting for Prestressing Tendons in to 10 CFR Part 50, "Licensing of Production and Containment Structures," could significantly reduce Utilization Facilities," requires, in part, that the con- the danger of widespread corrosion. However, the tainment be designed to permit (1) appropriate mechanism of corrosion in all conditions and situa-periodic inspection of all important areas and (2) an tions is not fully understood. Because many appropriate surveillance program. This guide parameters can influence the development of corro-describes, bases acceptable to the NRC staff for sion or stress corrosion, there is always an area of un-developing an appropriate surveillance program for certainty with regard to the corrosion of tendon steel, prestressed concrete containment structures with and it is necessary to monitor the structure in a man-grouted tendons. The Advisory Committee on Reac- ner that would reveal the existence of widespread cor-tor Safeguards has been consulted concerning this rosion. guide and has concurred in the regulatory position This guide outlines the recommendations for inser-B. DISCUSSION vice inspection of containments having grouted Inservice inspection of prestressed concrete con- tendons of sizes up to an ultimate strength of approx-tainment structures with grouted tendons is needed to imately 1300 tons (11,000 kN) and consisting either verify at specific intervals that the safety margins of parallel wires or of one or several strands. The provided in the design of containment structures have detailed recommendations of the guide are not direct-not been reduced as a result of operating and en- ly applicable to grouted tendon containments having vironmental conditions. Grouting of tendons to bar tendons. However, the inservice inspection protect them against corrosion is a proven program for grouted tendon containments with bar technology in other types of structures. However, tendons may be developed using the principles in this there is as yet no real experience to adequately define guide and will be reviewed by the NRC staff on a the long-term characteristics of containment struc- case-by-case basis. This guide does not address the in-tures with grouted tendons. The major concern in service inspection of prestressing foundation anchors. containment structures with grouted tendons is the If they are used, the inservice inspection program will possibility that widespread corrosion of the, tendon be reviewed by the N RC staff on a case-by-case basis, steel may occur and remain undetected. The major Inservice inspection of the containment liner and factors influencing the occurrence of corrosion are (1) penetrations is also not addressed in this guide. the susceptibility of the tendon steel to corrosion, (2) The simplest means of monitoring these prestres-the degree of exposure of the tendon steel to a sed concrete structures would be to ascertain the
- The substantial number of changes in this revision has made it amount of prestress at certain strategically located impractical to indicate the changes with lines in the margin. sections in the structure. However, it is generally felt that available instrumentation for concrete, i.e.,
t For the purpose of this guide, a tendon is defined as a tensioned steel element consisting of wires, strands, or bars anchored at each strain gages, stress meters, and strain meters, is not end to an end anchorage assembly. reliable enough to provide such information. When USNRC REGULATORY GUIDES Comments should be sent to the Secretary of the Commission, US. Nuclear Regu. Regulatory Guides are issued to describe and make available to the public methods latory Commission, Washington. D.C. 20555. Attention: Docketing and Service parts of the Commission's acceptable to the NRC staff of implementing specific regulations. to delineate techniques used by the stall in evaluating specific problems The guides are issued in the following ten broad divisions: or postulated accidents, or to provide guidance to applicants. Regulatory Guides are not substitutes for regulations, and compliance with them is not required. I. Power Reactors 6. PrOducts Methods and solutions different from those set out in the guides will be accept- 2. Research and Test Reactors 7. Transportation able if they provide a basis for the findings requisite to the issuance or continuance 3. Puels and Materials Facilities a. Occupational Health of a per 4 r.nEironmental and Siting 9. Antitrust Review mit or license by the Commission. 5. Materials and Plant Protection 10. General Comments and suggestions for improvements in these guides are encouraged at all Requests for single copies of issued guides (which may be reproduredl or for place-times, and guides will be revised, as appropriate. to accommodate comments and ment on an automatic distribution list for single copies of future guides in specific to reflect new information or experience. This guide was revised as a result of divisions should be made in writing to the US. Nuclear Regulatory Commisson., substantive comments received from the public and additional staff review. Washington, D.C. 20555, Altentioný Director. Division of Document Control.
FM 6.3 Exhibit 2 page 2 of 12 instrumentation that either can be recalibrated or concrete creep and shrinkage and relaxation of the tendon steel. replaced in case of a malfunction or is proven to be sufficiently reliable is developed, monitoring the prestress level would be a desirable means of assess- The measurement of forces in ungrouted test tendons would provide a quantitative means of I ing the continuing integrity of prestressed concrete structures with grouted tendons. verifying the design assumptions regarding the volumetric changes in concrete and the relaxation of Another means of monitoring the functionality of prestressing steel. If some lift-off readings (or load the containment structure would be to subject it to a cell readings) indicate values lower than the expected pressure test and measure its behavior under pres- low values, checks should be made to determine if sure. Industry comments indicate that an inservice in- such values are due to corrosion of wires of un-spection program based on the test of overall func- grouted tendons or to underestimation of prestress-tionality is preferable. ing losses. The plant need not be shut down or main-tained in a shutdown condition during such an This regulatory guide provides two acceptable evaluation period. These tendons may also serve as alternative methods of inspecting containment struc- an investigative tool for assessing the structural con-tures with grouted tendons: (1) an inservice inspec- dition after certain incidents that could affect the tion program based on monitoring the prestress level containment. by means of instrumentation, and (2) an inservice in- 2. MONITORING ALTERNATIVES FOR spection program based on pressure-testing the con- GROUTED TENDONS tainment structure.
- a. Monitoring of Prestress Level (Alternative A)
The detailed inspection program outlined in this guide is applicable to a sphere-torus dome contain- After the application of prestress, the prestressing ment having cylindrical walls about 130 feet (40 m) in force in a tendon decreases owing to the interaction diameter and an overall height of about 200 feet (61 of such factors as: m) with three groups of tendons, i.e., hoop, vertical, (1) Stress relaxation of the prestressing steel; and dome. For the purpose of this guide, such a con-tainment is termed the "reference containment." The (2) Volumetric changes in concrete; recommendations in the guide may be used for similar containments with cylindrical walls up to 140 (3) Differential thermal expansion or contraction feet (43 m) in diameter and an overall height up to between the tendon, grout, and concrete; and 210 feet (64 m). (4) Possible reduction in cross section of the wires For containments that differ from the reference due to corrosion, including possible fracture of the containment or are under a controlled environment, wires. the inservice inspection program may be developed using the concepts evolved in this guide and the In this alternative, the prestress level is monitored guidelines in Appendix A. at certain strategically located sections in the contain-ment. Thus it is a sampling procedure in which The inservice inspection program recommended in degradation in the vicinity of the instrumented sec-this guide consists of: tion will be detected by evaluation of the instrumen-tation readings. However, if corrosion occurs at loca-
- 1. Force monitoring of ungrouted test tendons; tions away from the instrumented sections, it would
- 2. Monitoring performance of grouted tendons by have to produce gross degradation before the in-strumentation readings would be affected.
- a. Monitoring of prestress level, or
- b. Monitoring of deformation under pressure; The prestressing force imparted to the structure by and a grouted tendon system could be monitored by an
- 3. Visual examination. appropriate combination of the following methods:
- 1. FORCE MONITORING OF UNGROUTED (I) Monitoring the tensile strains in the wires of a TEST TENDONS tendon; Some tendons (otherwise identical) are left un- (2) Evaluating the prestress level at a section in the grouted and are protected from corrosion with structure from readings of appropriately located grease. The changes observed in these tendons are not strain gages or strain or stress meters at the section intended to represent the changes due to environmen- (see Refs. I through 7).
tal or physical effects (with respect to corrosion) in the grouted tendons. Instead, these test tendons will Method (1) above is useful for direct monitoring of be used as reference tendons to evaluate the extent of prestressing force in a tendon. However, the installa-1.90-2
page 3 of 12 FM 6.3 Exhibit 2 lion of the instrumentation required for this method anchorage takeup, and friction. The 8% bandwidth needs careful attention during installation and would amount to between 40% and 70% of the total grouting of the tendons. Moreover, strain gages in- time-dependent losses. stalled on the prestressing wires of a tendon will not detect the loss of force due to relaxation of prestress- Alternative A is based on the use of instrumenta-ing steel. Allowance for this can be based on relaxa- tion. Many of these instruments have to be built into tion data for the prestressing steel used. the structure in such a manner that they can be neither replaced nor recalibrated. It is quite likely Evaluation of strain gage and stress meter readings that such built-in instrumentation may not remain requires a full understanding of what makes up the reliably operable throughout the life of the structure. readings, e.g., elastic, creep, and thermal strain or Recognizing such a possibility, the guide provides for stress components. Strain gage readings will consist an alternative of pressure testing (Alternative B) of elastic strains corresponding to the prestressing when the data obtained from instrumentation stress in concrete and strains due to creep and readings are found to be questionable. shrinkage of concrete.. Strains from creep and b. Monitoring of Deformation Under Pressure shrinkage of concrete can vary between 1.5 and 2.5 (Alternative B) times the elastic strains in concrete. However, there are methods that can be used to isolate these effects. Testing the containment under pressure and Three such methods are: evaluating its elastic response has been proposed as a means of assessing the integrity of the containment. (1) Calculate average creep and shrinkage strains The elastic response under pressure testing is primari-from the time-dependent losses measured on the un- ly a function of the stiffness of the structure. Any grouted tendons. significant decrease in the stiffness of the structure due to loss of prestress would be the result of crack-(2) Use stress meters at sections where strain gages ing of the structure. Because of the insensitive and in-are used. direct relationship, between the prestressing force and the elastic response of the structure, such a method (3) Use special strain meters that respond only to cannot be used to establish the existing prestress level volumetric and temperature changes in concrete at various sections. However, comparison of the con-(Ref. 7). dition and deformation of the structure during the ISI (Inservice Inspection) pressure testing with those A sufficient number of temperature sensors instal- during the ISIT (Initial Structural Integrity Testing) led at the sections where instrumentation is located pressure testing could provide a basis for evaluating can be useful in isolating the thermal effects. It is the functionality of the structure. This method has recognized that the raw instrumentation readings can been accepted* previously by the NRC staff on the be deceptive, and adjustments may be necessary to condition that the containment be designed conser-account for the calibration constants and vatively so that there will be no cracking (or only temperature effects. The interpretation and evalua- slight cracking at the discontinuities) under the peak tion of the results will be simplified if the instrumen- test pressure. Section III, Division 2, of the ASME tation is provided at sections away from structural Code (Ref. 8) allows a 33-1/3% increase in the al-discontinuities. The applicant should provide suf- lowable stress in tensile reinforcement under a test ficient redundancy in the instrumentation to permit condition. The NRC staff has accepted this al-the evaluation of anomalous readings and the isola- lowance on the assumption that it is only a one-time tion of a malfunctioning gage. One such combination loading (i.e., during the ISIT). However, if such would be two strain gages and one stress meter at each face of a section. testing is to be performed a number of times during the life of the containment structure, it is prudent not to use this allowance in order to avoid or minimize After appropriate use has been made of the methods and instruments available, an average stress gradual propagation of cracking during subsequent and an average prestressing force at a section can be pressure tests. evaluated. Even though the predicted prestressing The locations for measuring the deformations un-force corresponding to a specific time may include der pressure should be based on the recommenda-adequate consideration for creep of concrete and tions of this guide. For a meaningful comparison of relaxation of prestressing steel, the chance that the the deformations, it is recommended that the loca-value based on measurements will compare well with tions where the deformations are to be recorded have the predicted value is small. Hence it is recommended deformations larger than 0.06 inch (1.5mm) under the that an applicant establish a band of acceptable calculated peak containment internal pressure as-prestress level similar to that illustrated in Figure 1. It sociated with the design basis accident and that these is also recommended that the bandwidth not exceed 8% of the initial prestressing force at a section after
- Three Mile Island Nuclear Power Station Unit 2 and Forked considering the loss due to elastic shortening, River Nuclear Power Station.
1.90-3
FM 6.3 Exhibit 2 page 4 of 12 F. - Initial prestressing force at a section considering the losses due to elastic shortening. anchorage takeup, and friction. I PREDICTED PRESTRESS FORCE (CONSIDERING LOW TIME-DEPENDENT LOSSES) 0 Uj 0o 1 3 5 10 15 20 25 30 35 40 TIME IN YEARS Figure 1. Typical Band of Acceptable Prestress Level
/
/
FM 6.3 Exhibit 2 page 5 of 12 locations be approximately the same during the ISIT 3. The inservice inspection program should consist and the subsequent ISIs. This will require these loca- of: tions to be away from the areas of structural discon-tinuities. Thus the number of locations for measure- a. Force monitoring of ungrouted test tendons; ment of deformations in typical cylinder and dome areas will be in excess of those recommended in b. Periodic reading of instrumentation for deter-Regulatory Guide 1.18, "Structural Acceptance Test mining prestress level (Alternative A) or deforma-for Concrete Primary Reactor Containments." tions under pressure (Alternative B) at preestablished sections; and If an analysis of the effects of such parameters as normal losses in prestressing force, increase in c. Visual examination. modulus of elasticity of concrete with age, and dif-ferences in temperatures during various pressure tests 4. The inservice inspection should be performed at indicates that they could affect the deformations of approximately 1, 3, and 5 years after the initial struc-the selected points, these parameters should be con- tural integrity test and every 5 years thereafter. sidered in comparing the deformations during However, when an applicant chooses pressure testing various pressure tests. (Alternative B) as a part of the inspection, the fre-quency of inspections should be as indicated in
- 3. VISUAL EXAMINATION Figure 2.
Visual examination of structurally critical areas consisting of the areas of structural discontinuities 5. Alternative B may be substituted for Alternative and the areas of heavy stress concentration is recom- A by the applicant if, at some time during the life of mended. Reference 9 provides excellent guidance for the structure, the inspection based on Alternative A reporting the condition of concrete and should be does not provide satisfactory data. The details of used whenever applicable for reporting the condition such a substitution will be reviewed by the NRC staff of examined areas. on a case-by-case basis. There are numerous examples of the use of pulse velocity technique to obtain information concerning 6. If the containment base mat is prestressed, its the general quality level of concrete. Based on ex- proposed inspection program will be evaluated by the perience and experimental data (Refs. 10, 11, 12), a NRC staff on a case-by-case basis. pulse velocity of 14,000 ft/sec (4300 m/sec) or higher indicates a good to excellent quality of concrete. For normal weight concrete, a pulse velocity of 11,000 2. UNGROUTED TEST TENDONS ft/sec (3400 m/sec) or lower indicates concrete of questionable quality. Thus the technique can be used 1. The following ungrouted test tendons should be as part of the inspection of concrete containments installed in a representative manner: when the visual examination reveals a high density of wide (>0.01 in. or 0.25 mm) cracks or otherwise a. Three vertical tendons, heavy degradation. The detailed procedure and limitations of the techniques are described in b. Three hoop tendons, and Reference 13. c. Three dome tendons for the design utilizing three 600 families of tendons. C. REGULATORY POSITION
- 2. The ungrouted test tendons need not be in'addi-I. GENERAL tion to the design requirements.
- 1. All prestressed concrete containment structures with grouted tendons should be subjected to an inser- 3. The ungrouted test tendons and their vice inspection (ISI) program. The specific guidelines anchorage hardware should be identical to the provided herein are for the reference containment grouted tendons and their hardware.
described in Section B.
- 4. The ungrouted test tendons should be subjected
- 2. For containments that differ from the reference to force measurement by lift-off testing or load cells containment, the program described herein should to assess the effects of concrete shrinkage and creep serve as the basis for developing a comparable inser- and relaxation of the tendon steel. These data should vice inspection program. Guidelines for the develop- be evaluated in conjunction with the overall struc-ment of such a program are given in Appendix A to tural condition of the containment evident from the this guide. other examinations.
1.90-5
FM 6.3 Exhibit 2 page 6 of 12 I LRT dlcrt II a - I1 I 0 1 -1 -1 -- amj ý I -A DoI . -1 1 - I (10 CFR Part 50, I I I r I I 1* ____________ - 1-1-I APP. J) ISI SCH. 11111i=I- i PRESSURE I 1. I PN 15
-I I PA PD I
LEVELS I I L__________ __________£ ________A._ 0 1 5 10 15 20 25 30 35 TIME AFTER ISIT - YEARS 9* KEY PN - Normal Operating Pressure or Zero PO - Containment Design Pressure PA - Calculated Peak Internal Pressure Associated with the Design Basis Accident ILRT- Integrated Leak Rate Testing ISIT - Initial Structural Integrity Testing IS[ - Insece Inspection Figure 2. Schedule for Inservice Inspections (Alternative B)
FM 6.3 Exhibit 2 page 7 of 12
- 3. MONITORING ALTERNATIVES FOR c. Cyclic loading: 500 cycles of 600 psi (4.2 GROUTED TENDONS MPa) stress variation in compression.
3.1 Instrumentation for Monitoring the Prestress 2. The instruments should be protected against adverse effects of the expected environment in which Level (Alternative A) they will be located, e.g., electrolytic attack, including the effects of stray electric currents of a magnitude 3.1.1 Installation that may be encountered at the particular site and structure. They should be protected against
- 1. The prestressed cylindrical wall and dome temperature extremes to which they may be exposed should be instrumented. This instrumentation may be while the containment is under construction.
either embedded in the concrete or inserted into the structure so that it can be maintained or replaced. 3. The sensitivity of strain gages should be Instrument types, locations, and quantities should be specified; the drift or stability under the conditions in selected to provide the best representation of I and 2 above should be accounted for in the prestress level in the structure. A sufficient number of specified limits, or the gages should be subject to temperature sensors should be installed to isolate and recalibration in service. evaluate the effects of variations in temperature 4, The stress meters should be able to measure gradients on the instrument readings and observa-tions. Redundancy of the embedded instrumentation compressive stresses up to 2500*psi (17.2 MPa). should be based on a conservative estimate of the 3.1.3 Monitoring Instrumentation Operability probability of malfunction of the instrumentation to be installed. After the installation of the instrumentation, all embedded strain gages and stress meters should be
- 2. The instrumentation in the concrete should be read every two months until the initial structural in-arranged and distributed in such a manner as to per- tegrity test (ISIT) is performed. The response of the mit evaluation of the prestressing levels and should instrumentation during prestressing and pressure be located: testing (ISIT)' should be used, to confirm their operability. After the ISIT, the monitoring of the in-
- a. At.six horizontal planes to measure the hoop strumentation should be continued every two months prestressing levels; to confirm operability of the instrumentation until the first inservice inspection. The monitoring fre-
- b. Along three vertical tendons to measure ver- quency may be reduced to once every six months tical prestress levels; thereafter unless local conditions or special circum-stances dictate more frequent readouts. The
- c. Along three dome tendons for the design us- operability of the instrumentation should also be ing three families of 60' tendons. confirmed during subsequent pressure tests. If anomalous readings are obtained, the reason for such
- 3. Sections through the structure should be readings should be determined. If it is determined selected- at a minimum of four locations in each that they result from defective gages, 'the basis for horizontal plane, three locations along each vertical such a determination should be justified.
tendon, and two locations along each dome tendon (see Figure 3). At these sections, the prestress level 3.2 Monitoring Deformation Under Pressure (Alter-should be monitored by (a) a combination of stress native B) meters or strain gages in concrete or on rebar at a minimum of two points through the section or (b) When it is planned to use this alternative as a part strain gages directly on tendon wires with a minimum of the total inservice inspection program, it is recom-of 3% of the tendon wires instrumented. mended that the design of the containment structure include the following considerations: 3.1.2 Characteristics
- 1. Membrane compression should be maintained
- 1. Instrumentation provided for the determination under the peak pressure expected during the ISI tests.
of concrete prestress level should be capable of effec-tive use over the life span of the containment struc- 2. The maximum stress in the tensile reinforcing ture within specified operational limits under the fol- under the peak pressure expected during the ISI test lowing conditions, unless otherwise defined by the should not exceed one-half the yield strength of the designer and approved by the NRC staff: reinforcing steel (0.5fy).
- a. Humidity: 0% to 100%; 3.2.1 Pressurization
- b. Temperature: 00 F (-18°C) to 200'F (93*C); 1. During the first inspecticn, the containment and structure need not be pressurized.
1.90-7
FM 6.3 Exhibit 2 page 8 of 12 DT-1 DT-2 DI-2 DT-3 DOME TEND ONS AT 600 o0 VI-1 VT-1 VI-2 VT-2 VI-3 VT-3 KEY
- ~HI-1 -- I - -- I~m.I-I HT, VT, DT - HOOP, Vertical, Dome HI-2 I- -.- i HT-1 Ungrouted Test Tendons.
1112 -I -- I,- -- HI - Horizontal Planes to be Selected
- HI-3 - I I for Instrumentation.
VI & DI - Vertical & Dome Tendons HT-2 to be Identified for Instrumentation. HI-4 - I Four Sections Along HI Planes, Three Sections Along VI Tendons, Two Sections Along DI Tendons to be Selected for Monitoring Prestress Level. HT-3 *- Shows Selection of Sections Along HI-6 One Horizontal Plane, One Vertical Tendon, and One Dome Tendon. 7 2700 300 1500 CONTAINMENT CYLINDER - DEVELOPED Figure 3. Containment Diagram Showing Typical Locations of Test Tendon'>-=-I Instrumentation
FM 6.3 Exhibit 2 page 9 of 1-2
- 2. During the second and third inspections, the 3. Local areas around penetrations that transfer containment structure should be subjected to a max- high loads to the containment structure (e.g., around imum internal pressure, of 1.15 times the containment high-energy fluid system lines).
design pressure.
- 4. Other areas where heavy loads are transferred
- 3. During the fourth and subsequent inspections, to the containment structure (crane supports, etc.).
the containment structure should be -subjected to a maximum internal pressure equal to the calculated A visual examination of structurally critical areas peak internal pressure associated with the postulated should be scheduled during all pressure tests while design basis accident. the containment is at its maximum test pressure, even if visual examinations of these areas have been con-ducted at other times. 3.2.2 Instrumentation and Deformations 4.2 Anchorage Assemblies
-1. Instrumentation similar to that used during the ISIT should be installed prior to the pressure testing Exposed portions of the tendon anchorage as-for measurement of 'overall deformations at the sembly hardware or the permanent protection selected points. thereon (whether it be concrete, grout, or steel cap) should be visually examined by sampling in the fol-
- 2. The limit of accuracy of readings of the instru- lowing manner:
ments to be used should be specified by means of an error band so that a meaningful comparison of defor- 1. A minimum of six dome tendons, two located in mations measured during the ISIT and ISI can be each 600 group (three families of tendons) and ran-made. domly distributed to provide representative sampl-ing,
- 3. The points to be instrumented for the measure-ment of radial displacements should be determined in 2. A minimum of five vertical tendons, randomly six horizontal planes in the cylindrical portion of the. but representatively distributed, shell, with a minimum of four points in each plane (see Figure 3). 3. A minimum of ten hoop tendons, randomly but representatively distributed.
- 4. The points to be instrumented for the measure-ment of vertical (or radial) displacements should be For each succeeding examination, the tendon determined as follows: anchorage areas to be examined should be selected on a random but representative basis so that the sample
- a. At the top of the cylinder relative to the base, group will change each time.
at a minimum of four approximately equally spaced azimuths. The inservice inspection program should define the defects the inspector should look for during visual ex-
- b. At the apex of the dome and one intermediate amination of the exposed anchor hardware and point between the apex and the springline, on at least protection medium and should establish the cor-three equally spaced azimuths. responding limits and tolerances. Special attention should be given to the concrete supporting the anchor
- 5. The intermediate pressure levels at which the assemblies, and any crack patterns at these points deformations at the selected points are to be should be observed and analyzed.
measured should correspond to those for the ISIT.
- 5. REPORTABLE CONDITIONS 5.1 Inspection Using Alternamive A
- 4. VISUAL EXAMINATION If the average prestress force along any tendon falls 4.1 Structurally Critical Areas below the acceptable band (see Figure I), the condi-tion should be considered as reportable.
A visual examination should be performed on the following exposed structurally critical areas: If the prestress force determined at any section falls below the design prestress force, the condition should
- 1. Areas at structural discontinuities (e.g., junction be considered as reportable.
of dome and, cylindrical wall or wall and base mat). 5.2 Inspection Using Alternative B
- 2. Areas around large penetrations (e.g., equip-ment hatch and air locks) or a cluster of small If the deformation measured under the maximum penetrations. test pressure at any location is found to have in-1.90-9
FM 6.3 Exhibit 2 page 10 of 12 creased by more than 5% of that measured during the 6. REPORTING TO THE COMMISSION ISIT under the same pressure, the condition should be considered as reportable. The reportable conditions of Regulatory Position C.5 could be indicative of a possible abnormal de-I 5.3 Reportable Conditions for Visual Examinations gradation of the containment structure (a boundary designed to contain radioactive materials). Any such If the crack patterns observed at the structurally condition should be reported to the Commission.* critical areas indicate a significant decrease in the spacing or an increase in the widths of cracks com- D. IMPLEMENTATION pared to those observed during the ISIT at zero pres-sure after depressurization, the condition should be The purpose of this section is to provide informa-considered as reportable. tion to applicants and licensees regarding the NRC staff's plans for using this regulatory guide. If the visual examination of the anchor hardware indicates obvious movements or degradation of the Except in those cases in which the applicant anchor hardware, the condition should be considered proposes an acceptable alternative method for com-as reportable. plying with specified portions of the Commission's regulations, the method described herein will be used If the anchor hardware is covered by permanent in the evaluation of submittals in connection with protection and the visual examination reveals a construction permit applications docketed after degradation (e.g., extensive cracks or corrosion October 1, 1977. stains) that could bring into, question the integrity and effectiveness of the protection medium, the con- If an applicant wishes to use this regulatory guide dition should be considered-as reportable. in developing submittals for applications docketed on or before October 1, 1977, the pertinent portions of 5.4 Reportable Conditions for Ungrouted Test the application will be evaluated on the basis of this Tendons guide. When the force monitoring (by liftoff or load cell)
- The report to the Commission should be made in accordance of ungrouted test tendons indicates a prestress force with the recommended reporting program of Regulatory Guide below the acceptable band (see Figure 1), the condi- 1.16, "Reporting of Operating Information-Appendix A tion should be considered as reportable. Technical Specifications."
1.90-10
page 11 of 12 FM 6.3 Exhibit 2 APPENDIX A GUIDELINES FOR DEVELOPING THE INSERVICE INSPECTION PROGRAM FOR CONTAINMENTS (OTHER THAN REFERENCE CONTAINMENT DISCUSSED IN THE GUIDE) WITH GROUTED TENDONS Ungrouted Tendons Monitoring Deformations Under Pressure (Alternative B) Three ungrouted tendons should be provided in The number of locations (N) to be selected for each group of tendons (e.g.,vertical, hoop, dome, in- measuring the deformations under pressure should be verted U). determined as follows: Instrumentation (Alternative A) For radial deformations of cylinder, The following criteria should be used to determine Surface Area of Cylinder injsquare feet the number of sections (N) to be monitored for each (square meters)I group of tendons: N =2700 (250) Actual Area Prestressed by a Group of Tendons K x Area Monitored by a Set of Instruments but not less than 12.. at a Section (determined as SxL) where For vertical deformations, of cylinder, S = spacing of tendons in feet (meters) N-=4 L = length of a tendon monitored by a set of For radial or vertical deformations of dome, instruments- may be considered as 12 ft (3.66m) and K is determined as follows: For containments under uncontrolled environment Surface Area of Dome in square feet N =(square meters) and having continuous tendon curvature, 2700 (250) K !S100 but not less than 4 For containments under uncontrolled environment and having essentially straight tendons, K<160 For containments under controlled environment and having either straight or curved tendons. K<200 1.90-11
FM 6.3 Exhibit 2 page 12 of 12 APPENDIX B REFERENCES I. Jones, K., "Calculation of Stress from Strain in 6. Carlson, R. W., "Manual for the Use of Stress Concrete," U.S. Department of Interior, Bureau of Meters, Strain Meters, and Joint Meters in Mass Reclamation, Oct. 1961. Copies may be obtained Concrete." Copies may be obtained from Ter-from the Bureau of Reclamation, Denver Federal rametrics, A Teledyne Company, 16027 West 5th Center, Denver, Colorado. Avenue, Golden, Colorado 80401.
- 2. Irving, J., "Experience of In-service Surveillance 7. Raphael, J. M., Carlson, R. W., "Measurement and Monitoring of Prestressed Concrete Pressure of Structural Action in Dams," 1965. Copies may be Vessels for Nuclear Reactors," a paper presented at obtained from Terrametrics, A Teledyne Company, International Conference on Experience in the 16027 West 5th Avenue, Golden, Colorado 80401.
Design, Construction and Operation of Prestressed Concrete Pressure Vessels and Containments for 8. "Code for Concrete Reactor Vessels and Con-Nuclear Reactors, University of York, England, tainments," American Concrete Institute Committee Sept. 1975. Copies may be obtained from J. C. 359 and American Society of Mechanical Engineers Mundy, Publication Liaison Officer, Mechanical Subcommittee on Nuclear Power, 1975. Copies may Engineering Publications Limited, P.O. Box 24, be obtained from the American Society of Northgate Avenue, Bury St. Edmunds, Suffolk, Mechanical Engineers, 345 E. 47th St., New York, IP326BW. N.Y. 10017 or from the American Concrete Institute, P.O. Box 19150, Redford Station, Detroit, Michigan
- 3. Hill, H. T., Durchen, N. B., Brittle, W. F., 48219.
"Structural Integrity Test of Prestressed Concrete Containments," a paper presented at. International 9. "Guide for Making a Condition Survey of Conference on Experience in the Design, Construc- Concrete in Service," Reported by A0 Committee tion and Operation of Prestressed Concrete Pressure 201. Copies may be obtained from the American Vessels and Containments, University of York, Concrete Institute, P.O. Box 19150, Redford Station, England, Sept. 1975. Copies may be obtained from J. Detroit, Michigan 48219.
C. Mundy, Publication Liaison Officer, Mechanical Engineering Publications Limited, P.O. Box 24, 10. Whitehurst, E. A., "Evaluation of Concrete Northgate Avenue, Bury St. Edmunds, Suffolk, Properties from Sonic Tests," ACI Monograph No. IP326BW. 2. Copies may be obtained from the American Concrete Institute, P.O. Box 19150, Redford Station,
- 4. Browne, R. D., Bainforth, P. B., Welch, A. K., Detroit, Michigan 4821'9.
"The Value of Instrumentation in the Assessment of Vessel Performance During Construction and Ser- 11. Leslie, J. R., Cheesman, W. J., "An Ultrasonic vice," a paper presented at International Conference Method of Studying Deterioration and Cracking in on Experience in the Design, Construction and Concrete Structures," ACI Journal, Proceedings V.
Operation of Prestressed Concrete Pressure Vessels 46, No. 1, Sept. 1949. Copies may be obtained from and Containments for Nuclear Reactors, University the American Concrete Institute, P"0. Box 19150, of York, England, September 1975. Copies may be Redford Station, Detroit, Michigan 48219. obtained from J. C. Mundy, Publication Liaison Of-ficer, Mechanical Engineering Publications Limited, 12. Van Zelst, T. W., "Concrete Quality Control P.O. Box 24, Northgate Avenue, Bury St. Edmunds, Instruments," ACI Journal, June 1975. Copies may Suffolk, IP326BW. be obtained from the American Concrete Institute, P.O. Box 19150, Redford Station, Detroit, Michigan
- 5. Arthauari, S., Yu, C. W., "An Analysis of the 48219.
Creep and Shrinkage Effects Upon Prestressed Concrete Members Under Temperature Gradient 13. "Standard Method of Test for Pulse Velocity and Its Application," Magazine of Concrete Through Concrete," ASTM Designation C597-71. Research, Volume 19, Number 60, Sept. 1967. Copies Copies may be obtained from the American Society may be obtained from the Cement and Concrete As- for Testing and Materials, 1916 Race Street, sociation, Wexham Springs, SLOUGH SL 3 6 PL. Philadelphia, Pennsylvania 19103. 0-12 I I
FM 6.3 Exhibit 3 page 1 of 10 H 1/1* Overview of the Use of Prestressed Concrete in U.S. Nuclear Power Plants H. Ashar Division of Engineering Technology. Q1.ice of Regulator,1 Research, LUS Nuclear Regulatori Conunission. W$ashington. D.C. 20555. U'.S.A. D.J. Naus Oak Ridge National Laboratory. P.O. Box Y, Bldg. 9204-1. MS /6, Oak Ridge, Tennessee 37830, U.S.A. Abstract The containment system of a nuclear power plant provides a key part of tile overall plant's engineered-safety features. The structure serves as the final barrier against release of any radioactive fission products to the environment and consideration of public safety is one of the primary criteria in providing such a barrier. Originally tle containment was envisioned as a static pressure envelope fabricated of steel and which would adequately contain the fission products released from the primary system during any credible accident scenario. As the size of the nuclear power plants increased, the costs of fabricating containment structures from stress-relieved steel plate became significant and it became advantageous to fabricate the containments of concrete. In addition to economic advantages, the concrete containments could be fabricated in vir-tually any size (thickness) and shape, they generally utilize indigenous materials for their construction, and they exhibit a ductile mode of failure (leak before break) which is pre-dictable and observable. The paper outlines the extent of the use of prestressed concrete containments in nuclear power plants. However, the accident at Three Mile Island has changed the design parameters associated with the containment. In addition to containing the radio-activity during a postulated maximum LOCA, future containment designs should also provide for pressures generated during degraded core accidents. The change might give a slight edge to the application of prestressing in containmant design. The evolution of large size prestressing systems in the United States and abroad has been the result of the need to resist high pressures with the minimum number of tendons. Furthermore, corrosion inhibiting materials evolved simultaneously with the use of large size prestressing tendons. Cement grout and organic-petrolatum-based compounds needed to be specially formulated to assure thorough penetration through the tendon elements. Early in the development of prestressed concrete containments extensive dialogue occurred between the Nuclear Regulatory Commission (known then as the Atomic e use ot port an cement grout as a corrosion inhibitor. Concern by the regulators relative to the inability to inspect the prestressing tendons to insure their structural integrity resulted in the issuance of two regulatory guides (RGs) by the NRC: (i) "Qualifications for Cement Grouting for Prestressing Tendons in Containment Structures (RG 1.107)" and (2) "Inservice Inspection of Prestressed Concrete Containment Structures with Grouted Tendons (RG 1.90)." According to some observers this action eventually elimi-nated any incentives for the use of grouted tendons in prestressed concrete containments. I T the- 4oitzti*rtt a con I ion and functional capability of the ungrouted post-tensioning systems of prestressed concrete nuclear power plant containments be periodically assessed. This is accomplished, in part, systematically through an inset-vice tendon inspection program which must be developed and implemented for each containment. An overview of the essential elements of the inservice inspection requirements is presented and the effectiveness of these requirements is demonstrated through presentation of some of the potential problem areas which have been identified through the 'periodic assessments of the structural integrity of containments. Also, a summary of major problems which have been encountered with prestressed concrete construction at nuclear power plant containments in the United States is presented; that is, dome delamination, cracking of anchorheads, settlement of bearing plates, etc. The paper will conclude with an assessment of the over-all effectiveness of the prestressed concrete containments.
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FM 6.3 Exhibit 3 page 2 of 10
- 1. Introduction The principal use of prestressed concrete in the U.S. Nuclear Power Plants is in the construction of their containment structures. The containment structure (or containment) is-a vital engineering safety feature of a nuclear power plant. It encloses the entire reactor and reactor coolant system, and serves as the final barrier against release of radioactive fission products to the environment under postulated design basis accident (DBA) conditions.
To perform this function it is designed to withstand loadings associated with loss-of-coolant accident (LOCA) resulting from a double-ended rupture of the largest size pipe in the reactor coolant system. The containment is also designed to retain its integrity under low prob-ability (<10-4) environmental loadings such as those generated by earthquake, tornado and other site specific environmental events such as floods, seiche, and tsunami. Additionally, it is required to provide biological shielding under both normal and accident conditions, and is required to protect the internal equipment from external missiles, such as tornados or turbine generated missles and aircraft impact (where postulated). An additional functional requirement for containments has come into play since the accident at Three Mile Island. This requirement consists of maintaining the integrity of the containment under thermal and pressure loads (symmetrical or nonsymmetrical) ensuing from the detonation of hydrogen generated as a result of the metal-water (steam) reaction under degraded core conditions. Dry containments, such as the one at Three Mile Island, which are designed for high LOCA pressures, are not affected by this additional requirement; how-ever, the pressure suppression type containments (PWR ice-condenser, and some BWR contain-ments), designed for low LOCA pressures, are subjected to a thorough evaluation. This requirement may become one of the controlling criteria in the design of future containments. The functional requirements for containments are satisfied by various types of composite and hybrid steel-concrete constructions. Originally, the containment was envisioned as a static pressure envelope fabricated of steel with a separate radiation shield. As the size of the nuclear power plants increased, the costs of fabricating high pressure containment structures from stress-relieved steel plate became significant, and engineers started looking for alternatives such as steel-lined reinforced concrete which, in addition to economics, had advantages with respect to: improved construction schedules, earlier construction of interior containment structures and erection of equipment, and they can be designed to carry loads other than pressure and temperature (pipe anchors, equipment supports, etc.). Table I presents a distribution of construction types relative to various containment concepts utilized in the United States.
- 2. Evolution of Containment Configurations and Prestressing Systems 2.1 Containment Configurations The first prestressed concrete containments were partially prestressed in the vertical direction only with mechanically spliced reinforcing steel in the hoop direction and in the dome. Fully prestressed concrete containments were first built in the late 1960's being cylindrical in shape with shallow, dome and resting on a reinforced concrete slab. The dome is prestressed by three sets of tendons at 60' to each other and which are anchored at the side of the thickened dome-cylinder transition (ring girder). The cylinder walls are pre-stressed with both vertical and hoop tendons. The vertical tendons are anchored at the top to the ring girder and at the bottom of the foundation mat in specially constructed tendon galleries. Anchorage of the hoop tendons is to buttresses protruding from the cylindrical
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FM 6.3 Exhibit 3 page 3 of 10 wall. Initial containment designs used six buttresses with subsequent designs utilizing either three or four buttresses. Although anchorage of hoop tendons at three buttresses, as compared to six, increased the length of tendons and friction force, the combination of a low coefficient of friction (p<0.1) of pre-coated prestressing tendons and the reduced number of buttresses and anchorages produced cost savings. It was for these same reasons that the present-day prestressed concrete containment design evolved; that is, a cylinder with hemispherical dome using inverted-U tendons: 2.2 Prestressing Systems A posttensioned prestressing system consists of a prestressing tendon in combination with methods of stressing and anchoring the tendon to hardened concrete. Three general categories of prestressing systems exist, depending on the type of tendon utilized: wire, strand or bar. The wire systems utilize a grouping of parallel wires. Strand systems utilize groupings of factory-twisted wire. Bar systems utilize a grouping of high-tensile-strength steel bars. Anchorage is provided by wedges, button-heads, or nuts. The primary evolution in prestressing systems over the past few years has been with respect to system capacity. Prior to the advent of PCCs the prestressing systems were relatively small size; that is, less than 4.45 MN (500 ton) ultimate capacity. The require-ment to withstand high forces resulting from a combination of increased volumes and pressures of the dry pressurized-water reactor (PWR) containments necessitated the developinent of tendon systems with increased capacity [8.0 to 10.7 MN (900 to 1200 ton]. This development permitted increased spacing of tendons and reduced congestion by almost halving the number of tendons, tendon ducts and anchorages. The large size tendons were developed by using groupings of multi-wire, multi-strand, or bar systems. In the United States, the 8.9 MN (1000 ton) systems approved for use include: (1) BBRV (wire), (2) VSL (strand) and (3) Stressteel S/H (strand).
- 3. Evolution and Performance of Corrosion Inhibitors for Prestressing Tendons Prestressed concrete containments essentially are spaced steel structures since their strength is derived from a multitude of steel elements made up of deformed reinforcing bars and prestressing which are present in sufficient quantities to carry imposed tension loads.
The prestressing therefore plays a vital role in insuring the structural integrity of the containment throughout its 30- to 40-year design life. However, because the tendons are fabricated from high-strength steels [>1.6 GPa (230 ksi)] in the form of many relatively small-diameter wires or several strands fabricated from small-diameter wires, and the tendons can be subjected to sustained stresses up to 70% of their ultimate tensile strength, they are more susceptible to corrosion than ordinary reinforcing steels and must be pro-tected. Protection of the prestressing steel is generally provided by filling the ducts with portland cement grout or microcrystalline waxes (petrolatums) compounded using organic corrosion inhibitors. 3.1 Grouting The effectiveness of portland cement grout as a deterrent to corrosion of steel is evidenced by its performance history in prestressed concrete for over 50 years and its use in reinforced concrete construction for over 100 years. Corrosion of steel in correctly formulated concrete (cement) is prevented by the high alkalinity (p1 >12.5) of the Ca(OH) 2, which produces a passivating gamma iron oxide film on the steel surface [i, 2]. When corrosion does occur it is generally the result of a destruction of the passive layer. This
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FM 6.3 Exhibit 3 page 4 of 10 can result from reduction of the alkalinity associated with calcium hydroxide, calcium silicates, and aluminates [3]; from carbonation; or from the presence of high concentrations of chloride, sulfide or nitrate ions. Current grouting materials have evolved over the years to try to ensure that the prestressing materials are completely encapsulated to pre-vent corrosion; that is, grouts are specially formulated with water reducers and expansive agents to minimize the potentially deleterious effects of water separation and shrinkage. 3.2 Petrolatum-Based Coatings Although the introduction of petrolatum-based coatings as corrosion protection is much more recent than the use of portland cement grout, the coatings have gained prominence in PCCs in the United States because of their ease of inservice inspections. Additional advantages include: (1) encapsulation provides an approximate 50% reduction in friction factor which permits the use of longer tendons; (2) tendons may be relaxed, retensioned, and replaced as required; and (3)' during construction there is the possibility of more efficient scheduling of event sequence because the tendons are protected in the shop. Ths petrolatum-based coatings have evolved over the years to better attune the products to the nuclear unbonded tendon containment applications. Initially the product was a casing filler containing polar wetting agents, rust preventative additives, micro-crystalline waxes and proprietary items formulated to be water displacing, self-healing and resistant to electrical conductivity. The next generation of materials were formed by adding a plugging agent to the casing filler to increase the low flow point of the products (%39-C (lO0'F)] to keep them from seeking loose sheathing joints and flowing into concrete hairline cracks. A subsequent refinement involved incorporation of a light base number (3 mg KOH/gm of pro-duct) to provide alkalinity for improved corrosion protection. Finally, the current genera-tion of materials have evolved through a series of modifications to produce products which have been formulated to: increase the viscosity without sacrificing pumpability, raise the 0 0 congealing point to 57-63 C (135-145 F), increase the resistance to flow from sheathing joints, improve the water resistance, and raise the base number (35 mg KOH/gm product) to provide higher reserve alkalinity [4]. 3.3 Overview of the Performance of Prestressing Tendons [4-8] Prestressed concrete was first used for nuclear pressure vessels in 1960. As of April 1982, 27 prestressed concrete reactor vessels (PCRVs) were either in operation or scheduled for operation in Europe (France, United Kingdom, Spain and Germany) and the United States. In addition, there are 116 containments for pressurized water reactors (PWRs) and 33 con-tainments for heavy-water reactors (HWRs) commissioned or scheduled for commission through-out the world. Of the 116 containments for PWRs, 62 are in the United States. Reviews of the performance of the prestressing tendons in these structures have revealed that corrosion-related incidents are extremely limited. The evolution of corrosion inhibitors and the use of organic-petrolatum-based compounds designed especially for corrosion protection of pre-stressing materials have virtually eliminated corrosion of prestressing materials. The few incidences of corrosion that were identified, occurred early in the use of prestressed con-crete for containment structures. Where these failures involved tendons coated by .petroleum-based materials, the failures generally resulted from the use of off-the-shelf corrosion inhibitors that had not been specially formulated for prestressing materials. H H 1/1"
FM 6.3 Exhibit 3 page 5 of 10
- 4. Problems and Experiences During Construction of PCCs In general, the development of the various components of prestressing systems has been substantiated by careful study, testing and thorough evaluations by vendors, engineers and regulators. However, there have been a few occasions, either due to breakdown of the quality control, or due to nonscrutinized construction methods, where significant component failures have occurred. The following is a summary of such reported failures.
At Calvert Cliff nuclear plant (Units I and 2) some of the bearing plates under anchor heads of vertical tendons became depressed into the concrete [91. These depressions ranged in size from 0.8 mm (0.03 in.) to 4.8 mm (0.19 in.) and were generally on the inside edges of the plates. Removal of the plates identified the cause to be inadequate concrete com-paction under the plates which produced large size voids. The problem was corrected by detensioning the tendons of affected plates, reinstalling the plates, pressure grouting and retensioning. Failures occurred in the top anchor heads of 170-wire rock anchor tendons at Bellefonte nuclear plant (Units land 2) [10]. Anchorage of the 12.2 m (40 ft) long tendons to the rock was to be performed using a two stage grouting operation. Initially the tendons were td be grouted over about one-half their length to anchor the bottom heads. This was to be followed by addition of sufficient material to grout the tendons over their remaining length except for the final 0.9 to 1.5 m (3 to 5 ft.). Coupling of the containment vertical ten-dons to the rock anchors was to be by means of threaded coupling devices. However, during installation of the rock anchorages failures of the top anchor heads were observed just prior to the second stage of grouting. One anchor head failure was observed in which failure of 23 of 170 wires in a tendon occurred. (Figures 1-2 note some of the features of the anchor head cracking and fractures.) In-depth merallographical and fractographical examinations in conjunction with-the study of the environment indicated that the failures were the result of stress corrosion cracking of highly stressed AISI 4140 anchor heads in an aqueous environment of varying pH levels. In addition it was noted that during the period between the first and second stage grouting the top anchor heads were covered with grease cans filled with lime water having a pH of Ii to 13. In November 1979 four anchor heads of 179-wire tendons failed between 1 and 64 days after post-tensioning the Unit I containment at the Byron nuclear plant [11]. A thorough study of the chemistry, metallurgy and fracture phenomena indicated that the failure was due to tempered-martensite embrittlement. Failures were time delayed and occurred in a decreasing stress field. Concrete cracking and grease leakage were noted at various locations on the dome sur-face, predominately in the southern portion as shown in Fig. 3, after tensioning of approximately two-thirds of the dome tendons at Turkey Point Nuclear Power Plant (Unit 3) [12]. After a thorough examination of the concrete materials, construction method and pre-stress tensioning sequence, it was concluded that the dome delaminations were caused by the combined action of inadequate concrete consolidation and weakness at construction joints. Some engineers at NRC, however, believe that the delaminations were caused by exceeding the radial tensile strength of "weak" concrete and that well designed radial reinforcing would help prevent the situation from repeating in the domes of similar containments. In April 1976, surface cracking and voids in the dome concrete at Unit 3 of Crystal River Nuclear Power Plant were discovered (by accident) after the dome had been constructed
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FM 6.3 Exhibit 3 page 6 of 10 and fully post-tensioned (Fig. 4) [13]. Primary causes of the delaminations were thought to be the use of low quality coarse aggregate materials accompanied by high radial tension forces above the top tendons, and compression-tension interaction. Other potential contribut-ing factors were tendon misalignment and construction methods. Corrective measures included detensioning of some of the tendons, removal of the delaminated cap, installation of top orthogonal and radial reinforcing, and installation of a new cap concrete.
- 5. Regulatory Requirements and Effectiveness of Inservice Inspections of Prestressing Tendons 5.1 Background Early in the development of PCCs extensive dialogue occurred between the Nuclear Regula-tory Commission (known then as the Atomic Energy Commission) and industry relative to the use of portland cement grout as a corrosion inhibitor. Extensive tests were conducted to ensure adequate penetration of grout through vertical bar, hoop, and vertical strand tendons [14-16].
However, the regulators were concerned about not being able to positively check the integrity of the prestressing system throughout the life of the structure. As a result of discussions and public meetings, two regulatory guides were developed: (1) "Qualifications for Cement Grouting for Prestressing Tendons in Containment Structures (RG 1.107)" and (2) "Inservice Inspection of Prestressed Concrete Containment Structures with Grouted Tendons (RG 1.90)." This action permits the use of grouted tendons in containments without time consuming meetings and discussions. Though the intent was to thoroughly scrutinize grout material and installa-tion, and to periodicaily check the status of containment, these actions did not encourage the use of grouted tendons in PCCs. 5.2 Regulatory Requirements In the United States it is required that the condition and functional capability of the unbonded post-tensioning systems of prestressed concrete nuclear power plants be periodically assessed. This is accomplished, in part, systematically through an inservice tendon inspec-tion program which must be developed and implemented for each containment. The basis for conducting the inspections is presented in Regulatory Guide 1.35 "Inservice Inspections of Ungrouced Tendons in Prestressed Concrete Containment Structures (Rev. 2)." The intent of RG 1.35 is to provide utilities with a basis for developing inspection programs and to pro-vide reasonable assurance, when properly implemented, that the structural integrity of the containment was being maintained. The NRC does not require periodic reporting of inspection results except when the technical specification requirements (generally based on RG 1.35) of particular nuclear units are not met, or where there are obvious problems with materials, tendon prestress measurements, and/or an appreciable amount of cracking, grease leakage, etc. Because of the variety of factors such as tendon corrosion, anchorage failure, and material defects which can weaken the containment's structural integrity, the Guide has sought to examine all sources of potential problem areas before they become critical. Basic components ,covered by the Guide include: sample selection, visual inspection, prestress monitoring tests, tendon material tests and inspections, and inspection of the filler grease. Tendon sample selection criteria are specified for typical prestressed concrete contain-ments having a shallow dome-shaped roof on cylindrical walls. For the shallow-dome roof containment sample selection includes six dome tendons (two from each 600 group or three from each 90' group), five vertical tendons and ten hoop tendons. For the hemispherical dome-shaped roof containment sample selection criteria include 4% of the U-tendon population
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FM 6.3 Exhibit 3 page 7 of 10 (not less than four) and 4% of the hoop tendon population (not less than nine) with each result rounded to the nearest integer. If no problems are uncovered during the first three surveillances (scheduled 1, 3, and 5 years after the initial structural integrity test) then the criteria for sample selection are relaxed. For the shallow-dome roof containment the criteria become three dome tendons (one from each 60* group or one from each 90' group plus one additional randomly selected dome tendon), three vertical tendons and three hoop tendons. For the hemispherical-dome roof containment the criteria becomes: (1) 2% of the U-tendon population with results rounded off to the nearest integer, but not less than two; and (2) 2% of the hoop tendon population with the result rounded off to the nearest integer but not less than three. In all cases, the tendons are to be selected on a random but representative basis. Anchorage assembly hardware of all tendons selected for inspection are to be examined visually. The method used for removing grease in order to permit examination of the stress-ing washers, shims, wedges, and bearing plates should neither increase the effects of corrosion nor damage the steel. During integrated leak rate testing (ILRT), while the con-tainment is at its maximum test pressure, visual examination of the exterior of the concrete surface is performed to detect areas of widespread concrete cracking, spalling or grease leakage. Stress levels of each of the tendons in the sample selected for, inspection are monitored by performing lift-off or other equivalent tests. These tests include the measurement of the' tendon-force level with properly calibrated jacks and the simultaneous measurement of elonga-tions. Allowable elongations, jacking loads, tolerances, and the influences of such variables as temperature are to be predetermined. Acceptance criteria for the results state that the prestress force measured for each tendon should be within the limits predicted for the time of the test, No more than one tendon per sample may be considered defective or a reportable condition occurs, and the cause of the defect must be located and corrected. If only one tendon per sample is defective, then two additional tendons (one on each side of the defec-tive) are tested. If either or both of the two additional tendons are defective, a report-able condition occurs and the cause of the defect is located and corrected. Otherwise, the single defective tendon is considered unique and acceptable. Previously stressed tendon wires or strands from one tendon of each type are to be removed from the containment for examination over their entire length to determine if there is evidence of corrosion or other deleterious effects. At least three samples are to be cut from each wire or strand (each end and mid-length) and tensile tests conducted. Where either stress cycling is suspected or a potentially corrosive environment is thought to exist, tests simulating these conditions are to be conducted. At successive inspections, samples should be selected from different tendons. A sample of grease from each tendon in the surveillance is to be analyzed and the results compared to the original grease specification. The original grease specification is subject to the ASME Code which has limits on the amounts of impurities that may be present at the time of installation (10 ppm on the quantity of water-soluble chlorides, nitrates, and sul-fides, but no limit is specified for water content). Also the presence of voids in the grease is to be noted. The method for checking the presence of grease is to take into account: (1) minimum grease coverage needed for different parts of the anchorage system; (2) influence of temperatures variations; (3) procedure used to uncover possible voids in H I11"
FM 6.3 Exhibit 3 page 8 of 10 grease in trumpet; and (4) requirements imposed by grease specifications, qualification tests and acceptability limits. 5.3 Experiences from Inspections of PCCs [5, 71 Three instances of tendon force measurements (lift-off tests) have been reported where the force measured was lower than the minimum required prestress level (40 year losses con-sidered). Probably the most frequently found defect is missing buttonheads, but this problem is generally identified during construction or subsequent inservice inspections, and account is also taken in the design for a few non-effective wires in a tendon or group of tendons. Cracking of anchorheads of buttonhead systems made of AISI 4140 steel has also been reported (apparently due to hydrogen stress cracking); but these incidents also have been identified during construction. Two incidences have been reported of grease leakage through cracks to the exterior surface of the containment apparently due to a combination of inadequate duct joints and grease expansion due to thermal effects. There have also been two incidences of grease discoloration due to containments with the probable cause being entry of contaminated rain water into the tendon ducts during construction. Except for one instance in which a significant amount of water was found in several tendon ducts (despite presence of water, corrosion was found to be minor and steps were taken to eliminate recurrence), little water has been found during inspections. Only a few occurrences of wire corrosion have been identified, but these did not result in wire breaks and were so minor that component replace-ment was not required (it was concluded that the corrosion had occurred prior to filling the ducts with corrosion inhibitor). There have also been a few incidences of incomplete filling of the tendon ducts with corrosion inhibitors, but this has not caused any serious. diffi-culties and has been corrected.
- 6. Summary The evolution of containment systems in the-United States is presented as well as mcti-vations for changes. Prestressing systems and the mechanisms utilized for providing corro-sion protection of these systems are reviewed. A summary of experiences and problems during construction of PCCs is presented. Results obtained indicate that the few construction prob-lems which occurred were identified and remedied prior to a structure being placed in service.
A review of regulatory requirements relative to inservice inspections of prestressing tendons is presented. The few incidences of problems or abnormalities that were identified in these inspections were found to be minor in nature and did not threaten the structural integrity of the containments. In conclusion, the frequency of occurrence of incidences which could lead to a decrease in the functional capability of PCCs is small, especially considering the number of PCCs in service in the United States. Where problems did occur, they generally were the result of construction practices, and were identified and corrected during either the construction phase, the initial structural integrity test, or in subsequent inservice inspections. Thus it can be concluded that the inspections have been effective in achieving their desired objectives of uncovering and correcting potential problem areas.
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FM 6.3 Exhibit 3 page 9 of 10 References [I] SHALON, R., RAPHAEL, M., "Influence of Sea Water or Corrosion of Reinforcement," J. Am. Concrete Inst. 30 (12), 1251-68 (June 1959). [2] SCOTT, C.N., "Corrosion Protection Properties of Portland Cement Concrete," J. Am. Water Works Assoc. 57, 1038-52 (August 1965). [3] VERBECK, G. J., "Mechanisms of Corrosion of Steel in Concrete," Corrosion of Metals in Concrete, Am. Concr. Inst. Special Publication 49, 21-38 (1975). [4] NOVAK, C. W., Viscosity Oil Company, Chicago, personal communication to H. Ashar, Nuclear Regulatory Commission t(November 11, 1982). [5] Technical Report - An International Survey of In-Service Inspection Experience with Prestressed Concrete Pressure Vessels, FIP/3/6, F~d~ration Internationale de la Pre'contrainte, Wexham Springs, Slough, United Kingdom (April 1982). [6] NAUS, D. J., An evaluation of the Effectiveness of Selected Corrosion Inhibitors for Protecting Prestressing Steels in PCPVs, ORNL/TM/6479, Oak Ridge National Laboratory, Oak-Ridge, Tennessee (March 1979). (7] DOUGAN, J. R., Evaluation of In-Service Inspections of Greased Prestressing Tendons, ORNL/TM-8275, Oak Ridge National Laboratory, Oak Ridge, Tennessee (September 1982). [8] SCHUPACK, M., "A Survey of the Durability Performance of Post-Tensioning Tendons," J. Am. Concr. Inst. 75 (10), 501-510 (October 1978). [9] Study Report on Vertical Tendon Bearing Plates, Appendix 50 of Calvert Cliff Nuclear Power Plant Preliminary Safety Analysis Report, NRC-PDR Docket Nos. 50-317 and 50-319 (1972). [10] BERRY, W. E., STIEGELMEYER, W. N., BOYD, W. K., Examination of the Cracked Rock Anchor in the TVA Bellefonte Nuclear Power Plant, Battelle Columbus Laboratories, Columbus, Ohio (1976). [11] PRESSWALLA, S. E., Report on the Failure Investigation of Post-Tensioning Anchorheads Used in the Byron Nuclear Containment Structure, Inryco, Melrose Park, Illinois, NRC-PDR Docket Nos. 50-454 and 50-455 (1980). (12] Containment Dome Report Turkey Point Unit 3, Florida Power and Light Company, NRC-PDR Docket No. 50-250 (1972). [13] Reactor Building Dome Delamination Crystal River Unit 3, Florida Power Corporation, NRC-PDR Docket No. 50-302 (1976). [14] WERN, A. H., SCHUPACK, M., LARSEN, W., Prestressing System for H. B. Robinson Nuclear Power Plant, Proc. ASCE Power Division (March 1971). [15[ HAMSTEAD, G. A., et al., Testing of Large Curved Prestressing Tendons, Proc. ASCE Power Division (March 1971). [16] SCHUPACK, M., "Grouting Aid for Controlling the Separation of Water for Cement Grout for Grouting Vertical Tendons in Nuclear Concrete Pressure Vessels," Paper 151/75, Experienced in the Design, Construction and Operation of Prestressed Concrete Pressure Vessels and Containments for Nuclear Reactor, Institution of Mechanical Engineers, London (September 1975). Research sponsored by the Office of Nuclear Regulatory Research, U.S. Nuclear Regula-tory Commission under Interagency Agreements 40-551-75 and 40-543-75 with the U.S. Department of Energy under contract W-7405-eng-26 with the Union Carbide Corporation. By acceptance of this article, the publisher or recipient acknowledges the U.S. Government's right to retain a nonexclusive, royalty-free license in and to any copyright covering the article.
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FM 6.3 Exhibit 3 page 10 of 10 N m~7i 1t Z.9 Z ORNL PHOTO 0410-83 ORNL PHOTO 0411-83 119.1. Wpetne .o us frature facesoon o..f~ -ch., jA-BI-1: fot. Bs'e fc
- OFIN.DVVG 83-8792 Flt. 2. Sf51 photographs of5areas B. C and D in Fig. 1.
- 0 0
7Or ad lo Oransooio cu-ao aw 0 dOotnminmtion sc010 Fig. 3. EXtent of doeo do1ntratio55 io Unit 3 contatrsoe at Inijl Invetiogation detafl, 18 T.okey Point dimenSOIominm~co dotl[l a Fit. 4. Extent of do- d.1Inaoitiofl In Unit 3 contino-t at Crystal Riv-r
--10--H11 H I1 1"
FM 6.3 Exhibit 4 page 1 of 4 Florida Power CORPORATION
.1976 0...
5.1276-10 Mr. John Stol.z ..... Branch Chief Light Water Reactors 'Branch I Division of Project*'Management U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
Crystal River Unit #3 Docket No. 50-302
Dear Mr. Stolz:
We are today supplying you with our final"buiie if Dome Reactor '! to be incorporated in our interim report Delamination - June 11, 1976. 1.-.. These pages when properly inserted in the original. r'eport will provide you with a single document which will after'placemýnt become our final report on the-:dome delamination. In addition, we are furnishing a new cover insert-..*plac* the originIal, soas to more positively identif Y.fig doc;ument as the Final Report - Reactor Building Dome Di aitio -o " December 10, 1976. With this submittal, you have in your possession the required "final report regarding the repairs to the containment dome" called for on page 22-1, section 22 - Conclusions of the SER Supplement #2. Very truly yours, Asst. Vice President JTR/iw Attachment cc: Mr. Norman C. Moseley, Director w/Att. Region II, I&C Atlanta, GA General Office 3201 Thirty-fourth Street South
- P.O. Box 14042, St. Petersburg. Florida 33733 0! R210 21 ,
'io
FM 6.3 Exhibit 4. page 2 of 4 If the tensile capacity is based upon splitting tensile strength, the resulting value is about 8/f'. The maximum radial tension is around the top tendon layer where tLe meridional and hoop compression are less than 0.45 f'. Since the allowable tensile stress is 3/f&, the design criterion as shown in Figure 3-19 by the dashed line is well within the interaction curve. 3.3.4 Thermal Effects Two types of thermal effects considered were solar radiation (environmental) and tendon greasing (bulk filling).
- a. 'Solar Radiation The effect of solar radiation on the surface concrete temperature was calculated. In performing this calculation the initial condition assumed was 60°F throughout the dome thickness. The effect of solar radiation was calculated to heat the dome surface to 152 0 F. Subsequent to a six hour heat up period, the 6.0 hour gradient shown in Figure 3-20 was calculated. To determine if a thermal shock could have had a significant effect on the stress state in the dome, a sudden cool down due to a thunderstorm was postulated. Therefore, a step function of a six hour quench using a surface temperature of 50°F was assumed.
Figure 3-20 shows the gradients after the initial heat up (0.5 hr), just prior to quench (6.0 hr), after quenching (6.5 hr), and two points along the cooling period (8.0 hr and 12.0 hr). Using -the analytical model described in Section 3.3.2, and the gradients shown in Figure 3-20, the maximum tensile stress at the level of the centerline of the top tendon group was calculated to be 8psi. The solar radiational heat also had an affect at construction joint L-M during the three month construction delay. The conduit protruding from the joint had a different temperature than the surrounding concrete. This causes hoop tension around the conduit in the same way as that due to hot grease injection. The temperature gradient is as shown in Figure 3-21 and the maximum tension as calculated by plane strain element of computer program SAP IV (see Appendix D) is 280 psi. Based upon these studies it is unlikely that the solar effect by itself could have produced other than very limited cracking at the construction joint interface.
- b. Tendon Greasing The field records show that tendon greasing took place in two stages. Eight unstressed tendons were greased prior to stressing the tendons (with'the exception of three). The remainder were 3-7
FM 6.3 Exhibit 4 - page 3 of 4 greased about four months later, after all tendons had been stressed. The -second greasing operation was completed in a period of eight days. The grease was heated prior to injection to reduce its viscosity. According to available field records, the temperature of the grease at the tank outlet was in the range of 150-170 0 F. It was then pumped via a rubber hose into one tendon conduit at a time. After all the air had been purged from the conduit, pumping ceased and the conduit was sealed at 0 psig. During hot grease injection, the conduit heated more rapidly than the concrete due to the lower thermal conductivity of concrete. For a step change of temperature from conduit to concrete, the tensile stress in the concrete surrounding the conduit can be calculated from the theory of elasticity. Using the compatibility of radial displacements at the conduit-concrete interface,( 1l) the tensile stress is determined to be 11 psi/°F. The plane strain element of. the SAP IV program as shown in Figure 3-22 yields a tensile stress of 15 psi/°F for the identical condition. Based upon an averaging of field records of grease temperature in the storage tank and at the conduit outlet, a heat transfer I analysis was performed to establish the temperature gradients within the structure due to the greasing operation. The resulting gradients at a point approximately midway between ring girder and dome apex are shown in Figure 3-23. Using the plane strain element in the SAP IV computer program, shown in Figure 3-22, the maximum tension stress is approximately 80 psi, which occurs at the location where the thermal gradient drops to zero. It is recognized that variations in the greasing operation could produce more severe gradients and consequently higher concrete tensile stresses. The injection pressure of hot grease can also cause tension around the conduit. With the same kind of radial displacement compatibility calculation, the maximum grease pressure reported by the constructor of 85 psi causes 40 psi tension in the concrete by compatibility calculation(lI). The cases studied indicate stresses of sufficient magnitude to cause the delamination only when considered in conjunction with other effects. 3.3.5 Tendon Alignment To establish the accuracy of the positioning of the tendons within the dome, a survey was conducted to determine the actual dome thickness and the depth from the dome exterior surface to the top of the upper tendon group conduit. The results of the survey are shown in Figures 3-24 through 3-27. This shows that the conduit are high near the periphery and low at the apex and suggests that an increased curvature might exist. A study was performed to determine the significance of 3-8
FM 6.3 Exhibit 4 page 4 of 4 CONDUIT S TENDON CONCRETEE 15 NOTE.% AVG. TEMPE~kTURS CA5F SECTION MMV4WY BE.TWEE.N RING GIRDER 4 0Ot-E AkPE'V. INJECTION TIME= IOOSEC:. IL 0 10 N-. YTIMECTYINP.)MINUTES I/'** ui 0i 0 ELI 0 G 7 RkIA~L DISTkNCE. (INCHES5) TEmpep,ý.Tuze. GRAzDiENTS D uE To
.TENDoNi GREksiNcz 0
F-u R/u~es 3 -.
*o * .. ~~Fl46-.3-E-ibiA
. ""-N,% %
" .-,,Fr CRYSTA,. PIVER 1'1I- !,0. 3 page 1 of 3
*II. ACi'o R BUI II P ' )'r -SS 1 Gc SYSTEM
!'!:C SIL:;TIHCATION NV*3ER /C 2. CUT U LENGTH /*. -
SHOP WA,*X-E. ID: PC /Z / CR _ ____ FIELD WASHER ID: PC /L_0 CR- Z3Z. I. GAI/QA vendor inspecticn cover letter nuzcr-FPC g f5? DATE __Z__f_/7_ "
- 2. Da:e tendon re:eive', cn-site _,/6--7Y FMIR Nunber e r-3
- 3. Date installed in cenrd'uit 7- 7-yf Installation NCR's____________
Wires removed 0 Wires replaced C Total Ineffective wires 0
- 4. Date buttcnheaded 3 -7YButtonheading NCR's_______________
Bad wires 0 Accept. Reheads - * .Total Ineffective'wires 0
- 5. Date stressed /9-/!1 -79 ]tressing NCR's Date restressed Restressing NCR's SHOP END FIELD END TOTAL Elonga'tioni (1500 psi to 80-,. ult.)-Pred./Act. ,Z!f' WI2#i 0 /,Z &' /.Z tft-Off Pressure - Predicted/Actual / 7 OS'O#$ U //A N/0A Shim Thickness/80% Ultimate Pressure / 7"/ CO . J N/A Unseated/Broken Wires 0 Total effective wires after stressing / 3
- 6. Dae Bulk-filled /P-Z3-7y/ Bulk-Filling NCR's Time since installation- ý' Inlet Pressure I/ ~~ Outlet Temp. L 0 Date end caps refilled: Shop Field
- 7. Data compiled by '-* e 2t" Organization ____.
Da t e 2 _ _ _ __7_ _
- 8. Additional Co.-,znents:
.. 17 715
page 2 of 3 CRYSVLU' PIVU 1" 1 NO. 3 40
-- REACrOP. Pf; L MP, FV FI'KSS1 SYSTEM i ID--:;rICAT1O:, .,=.Z3R CUT LENGTH -
SHOP ID: PC /Z/ I,4A'E- CR ___7 FIELD WA_:ZR ID: PC /Z0 CR 17(o
- 1. GAI/QX vendor inspecticn cover letter number-FPC 0 _ __ __ DATE 2/2s-/7Y
- 2. Date tcndo reseivce- ern-site 1 '7-*/ RMR N,= ber 3G&03 &
- 3. Date installed in conduit 7 7-Y Installation NCR's _
Wires rcmoved Wires replaced W 0 Total Ineffective wires 0
- 4. Date buttcnheaded 7- Z Y 7- 1 Buttonheadin; LNCR's Bad wires 7 Accept. Reheads d-1 Total Ineffectivewires .3
- 5. Date stressed 9' 2 7 - 7Y Stressing NCR's Date restressed Restressing NCR's SHOP ELND FIELD END TOTAL Elongation (1500 psi to 807.' ult.)-Pred./Act. /Z70// , N/A ./Z* ;1k/ /Z tft-Off Pressure - Predicted/Actual . 8D /7 I / I " N/A Shim Thickness/80% Ultimate Pressure /34 /7770 / N/A Unseated/Broken Wires 0 Total effective wires after stressing /1 3
- 6. Date Bulk-filled /40- 2 3 -7 Bulk-Filling NCR's Time since installation.3%r -'0jd5 Inlet Pressure //P
- Outlet Temp. /22 Date end caps refilled: Shop Field
- 7. Data compiled by Organization Pa te -'11
- 8. Additional Co*.--ents:
q07 71A
* *'-.: = *page 3 of 3
.*4W,5 CRY. T[A P7VI R 11'1 9,. 3
,, .a. Ri:ACLoR i1UIL1I*:' PW.:;ý , ,S:,
N SYSIEM ID2'rIFICATlo:4 :;u:SER /Z k' l/ CUT LENGTH C '- 7 SHop W.ASPR ID: PC /Z/ CR S'_7 FIELD WAS-iER ID" PC /c.P CR (.a7
- 1. GAI/QA vendor inspecticn cover letter n,..zber-FC _ ___" __DATE 2/1Zr/ _/,y
- 2. Date tendon receive-2 cn-site // M('1 R'IR Number 3*O.3
- 3. Date installed in conduit 7 J - Installation NCR's Wires removed 0 Wires replaced 0 Total Ineffective wires
- 4. Date buttenheaded - Z7 - 7y? Buttonheading NCR's Bad wires _ Accept. Reheads 4" Total Ineffective wires /
- 5. Date stressed / /'-Y 7y! Stressing NCR's Date restressed Restressing NCR's SHOP END FIELD E'ND TOTAL Elongation (1500 psi to 80. ult.)-Pred./Act. /Z/ / 14 A//A, I /ZA06 ,/2/"'s ft-Off Pressure - Predicted/Actual 67*. f
/740D "'I NIA Shim Thickness/80% Ultinate Pressure 1I / /7"7 Z -j " N/A Unseated/Broken Wires Total effective wires after stressing / Z
- 6. Date Bulk-filled 3-30 7* Bulk-Filling NCR's Time since installation6 oW0,er,* j Inlet Pressure / e4 4 7" Outlet Temp. /27 Date end caps refilled: Shop Field
- 7. Data compiled by Organizational__o_.-____u__s_:
Date 7?
- 8. Additional Co-.zi-enrs:
7T7__71* .... . -.
raRA F lVi et'
'J.'
^ r--.--L.
iLAI U#JVE 1.1 iity c6h6
-_nAne 4 () C 11 pri nl- S qnen ,P.4
.,Drying Shrinka66,and Creep 88 0 pe fr'imsOnes and gabbrost lot 0
graavels, and quartzjite. Si'ncethe t ItXi 6 p6
.,be estimated from, the weigh.. tevfficient f thermo cent aggregate in the concrete iture, r Sanston.
erage mi X!te ofh;the. COminent
. vau~esa.sumng, ofasui concr70 the C*flcrete etoae Svarious rocktpes (both coarse arear.. fieageglk
. 'clsetofromthed .Sam - coeffi'umrn9 the Xerimetal-o 7 fo0prý cefficietefr, in Fig. 4-9. The dat- -: nh. .. .i9i Peaggregate frdatami "Fig o of thermal coefficients reportedi the P6ub-seselto th",
'0 I.e,Per-onl tesutedte.inCom-oist conditions, w hich is representative o f the Cond 'tio innhemooistin~
-etoftte
*20 ~ ncrete~~te pared to concrete in the moist state, thecorre sndpical mass concrete. Com-would show a slightly higher coefficientL, P rob a a rgonceteof-the aireaeried state.,
* ,uaty
, v s~areslt f increase inL density,
'4 IC C-z 2 Figure 4-8 Effect of cement 00 and pozzolan contents on- 4a.
temperature rise in concrete. _0 (From R. W. Carlson et al., Al't D-I I-1 7A Xd,. XZ108
. - .- . - "7 , 1979 .)
'TIME -DAYS o ,, l4'ls i 1 i~ e4 Ifune-fh "..
The useof'a low cemient content, aniASTM Type llportland cement instead of Type I, 0-
"anda parialsbstitution ofthe portland cement-by a pozzolan, are effective means by z I-
.which the adiabatic, temperature rise in mass concrete can be significantly reduced. w wiC-6-,
while maintaining a satisfactory level of strength, In this way the temperature rise in concrete cahrbte limiitedý,to 'about-16C. -A,partial substitution of the cement by "4 5 .6 7 ~' Figur 4-e Infuneo
- , ;9 '~li- Io I 2, aggiegate type:on itne . thece.i e6t-*
30v6lumneercent fpozzolan ca further reduce the temperature rise to a mere 13 'C. COEFFICIENT OF THERMAL EXPANSION' -ctient. oftherifial expansi*n*of OF AGGREGATE (MICROS TRAIN P.EIR*C) .:co.ncrete,;..' *. '. : Precoolingoffresh concrete isanothercommonly used method of controlling the subsequnt temperature drop. Often, chilled aggregates and ice shavings are specified for making mass concrete mixtures in-which -temperature of. fresh concrete Since the coefficient'of thermal e'xpansi'n.ofconcreote ifiir related-tothe cefficient - is limited tolO0C or less. Dunng theiemixing operation the latent heat needed for of expansion of the- aggregatepresent',.in mass concrete the.selectioniof an ggregate with*
- a lower coefficiehi-provideý atik ah&er aproach towardloweii gth ether ra iih.
-fusion of ic:iiith~drawnf.r6mother materialsiofthe concrete mixture, providing.
+,
Seconowical7l f* t h coefficientf thermalexpansion, when it is: become a ' sib;e-and 't cnlogically acceptable may under certain conditions DRYING- SHRINKAdt AND CREEP critictalfactor for crack:"prevention in.m -assconcrete. This is ,bec,se the fctsfrom- dy ing shrnkage and creep sirains in cqncrete are thermal shrin esti:-a is .ds o . - . Snot-the snerally,mthe(stress er ct. iestriutO t... .,. :.
- ., induig-hil-
. "' *n o t*.. th'*:,-* a me' (i e .,- .. o e co d t ° mof restr . .the. *fornier e ....,S ,nditionsof eufer e s misitstress-s~de s ~j r a ble to da c uss -
-and,the linarcoefficint P.terminrnedhbl h by by the the magritude of:the'temperature drop .... ,;:... . ..:.. . : *: ** v ',,fora Vatlaet)'o rear,ýOn it* f<- theS,**<
trolled prima boby~he.....linear .... coefficient iO
,i, P s6on o"- trofo ncrete, expansio t .. othe
....in turn, is con-, eaS itpis dee o r ...
pmqots aggregate. the latter is stress, rjl.ving)-.Rowever- f a are.*n The reported vuiOfte t hma-x ofhe' . -'b o th ph e n o men a to g eth er : FIrst ' tjbo * ,b dryi g 5 thudrrý, th st a i - time o-,rg a ein ,r tVery Portlan 'cemtientpastes of t*lier se* seeennd, t ae-.... t*h, . ... the crepr of rying*ce waI*terc*iemetn thermal ratiosfor expansion mortars fo resaturted Icntaintin 1:6 --- same source the hydrated ceme ,. apsoe-nflue-ce ta of efach, o th 00 tO cement/n~~turalsXl, snndfrccrete mixtures of different--ýcompstof r n d g en third,
.;:asimilar; e s a m ethat in-thfactors e a lly the "; : , L inthe w a yinfluence
*;.fourth, , n s f sh*ri*ei dryingF
. concrete ctu s ign ; a n~dfifth <b ra l-d ecrostrai the.i. a are e a pherm '- 1 , a d to i j 6Per 'C, respe-ctively 'T he co ef i i n of - - 1"00.x lO6-ie!anrgeend cannot be ignored intW11 lde',. < n" bo a.Mn n ~ o of co mM
-ute nlYpnd rocks'an d rn inerals ar s d o t 5( <
6'o partia , rew i,'rib e. . . - ~-,--- -~ - ~ -- __________
FM 6.3 Exhibit 7 page 1 of 1 Coefficient of Thermal Expansion (CTE) of concrete From P. Kumar Mehta, "Concrete: Structure, Properties, and Materials" (1986), pages 88 and 89.
- The coefficient of thermal expansion (CTE) of concrete depends on the CTE of the coarse aggregates;
- It varies in the range 6 to 12 xl0-6 /C;
- For limestone coarse aggregates, the CTE is close to 6 x 10-6 /°C; This compares with steel CTE close to 6 x 10-6 /°C.
1
Thermal Conducthvity - k - (W.mK) u68 iTit emperatp 1 of 3 25 125 225 Acetone 0.16 Acrylic 0.2 Air 0.024 Alcohol 0.17 Aluminum 250 255 250 Aluminum Oxide 30 Ammonia 0.022 Antimony 18.5 Argon 0.016 Asbestos-cement board 0.744 Asbestos-cement sheets 0.166 Asbestos-cement 2.07 Asbestos, loosely packed 0.15 Asbestos mill board 0.14 Asphalt 0.75 Balsa 0.048 Bitumen 0.17 T Benzene 0.16 . Beryllium 218 Brass 109 Brick dense 1.31 Brick work 0.69 Cadmium 92 Carbon 1.7 Carbon dioxide 0.0146 Cement, portland 0.29 Chalk 0.09 Chrome Nickel Steel (18% Cr, 16.3 8 % Ni) 1-,A1 +___,
rnmon Materials nmonMateialshttp://www.engineeringtoolbox.com/the) FM 6.3 Exhibit 8 page 2 of 3 L = Concrete, stone 1 1.7 1 1 1 uonstantan Copper 401 400 398 Conan (ceramic filled) 1.06 Corkboard 0.043 Cork, regranulated 0.044 Cork 0.07 Cotton 0.03 Carbon Steel 54 51 47 Cotton Wool insulation 0.029 Diatomaceous earth (Sil-o-cel) 0.06 Earth, dry 1.5 Ether 0.14 Epoxy 0.35 Felt insulation 0.04 Fiberglass 0.04 Fiber insulating board 0.048 Fiber hardboard. 0.2 0 Fireclay brick 500 C 1.4 Foam glass 0.045 Freon 12 0.073 Gasoline 0.15 Glass 1.05 Glass, Pearls, dry 0.18 Glass, Pearls, saturated 0.76 Glass, window 0.96 Glass, wool Insulation 0.04 Glycerol 0.28 Gold 310 312 310 Granite 1.7- 4.0 Gypsum or plaster board 0.17 Hairfelt 0.05 Hardboard high density 0.15 Hardwoods (oak, maple..) 0.16 Helium 0.142 Hydrogen 0.168 0 Ice (0°C, 32 F) 2.18 Insulation materials 0.035 -0.16 Iridium 147 Iron 80 68 60 Iron, wrought 59 Iron, cast 55 Kapok insulation 0.034 Kerosene 0.15 Lead Pb 35 Leather, dry 0.14 Limestone 1.26- 1.33 Magnesia insulation (85%) 0.07 Magnesite 4.15 Magnesium 156 Marble 2.08 -2.94 Mercury 8
ntmon Materials http://www.engineeringtoolbox.com/thei FM 6.3 Exhibit 8 page 3 of 3 Molybdenum 138 Monel 26 Nickel 91 Nitrogen 0.024 Nylon 6 0.25 Oil, machine lubricating SAE 50 0.15 Olive oil 0.17 Oxygen 0.024 Paper 0.05 Paraffin Wax 0.25 Pedite, atmospheric pressure 0.031 Periite, vacuum "0.00137 Plaster, gypsum 0.48 Plaster, metal lath 0.47 Plaster, wood lath 0.28 Plastics, foamed (insulation 0.03 materials) Plastics, solid Platinum 70 71 72 Plywood 0.13 Polyethylene HD 0.42 - 0.51 Polypropylene 0.1 -0.22 Polystyrene expanded 0.03 Porcelain 1.5 PTFE 0.25 PVC 0.19 Pyrex glass 1.005 Quartz mineral 3 Rock, solid 2-7 Rock, porous volcanic (Tuff) 0.5 - 2.5 Rock Wool insulation 0.045 Sand, dry 0.15-0.25 Sand, moist 0.25-2 Sand, saturated 2-4 Sandstone 1.7 Sawdust 0.08 Silica aerogel 0.02 Silicone oil 0.1 Silver 429 Snow (temp < 0°C) 0.05 -0.25 Sodium 84 Softwoods (fir, pine ..) 0.12 Soil, with organic matter 0.15 -2 Soil, saturated 0.6-4
..... .Steel, Carbon 1 .%
Stainless Steel J: 16
.. . . .. . . . .......... -I 17ffi 19 Straw insulation 0.09 Styrofoam 0.033-]_____ ___
Tin Sn 67 Zinc Zn 116 1 Urethane foam 0.02 1 4-Vermiculite 0.058 Vinyl ester 0.25
FM 6.3 Exhibit 9 I /'ýJ, I page 1of4
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evo d 41a b -( rh eQyM4 S~4A.3
FM 6.3 Exhibit 9 page 3 of 4 Li 355 4 (/4')t F 77 340 1 b8&-Q71k /X3V r-v-5 's cooJ'e-6 tv;-'k. F~1gu 3-So 6v~gk, 3r de-mot's tAm4td c--bove 7s bc4 ed v~ cý. 5e-
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FM 6.3 Exhibit 9 page 4 of 4 Ae4t rhes"0 veSee 'Yie+e ~2'4 A .e(/5/2Qf;4 *5 "4 COYIho.. L1 J a~- d ere c-ovsS'fe-nt m cc'A-a~tc, 5 AIC/ 0A-(O-YlC%6(OflS " e vte 3-23 ,P~Aofr~h S 1(1.{f /1,~, A '4-e6AW ie,4 *ttus-s s ee))ý;e"e aY'1~A 5ZLOF~ a f+e mpeAcp-tuee ?AoJ~e , Tfle A~t4~4 2c*.i, 2 . * "* ' Iwe- Y-lq ,
,d (ý 2,,o,(.-k-i~-?~-rhe $-oje S neotA -ri- p~Qe s l~y~e~4e~
(\ ('71 *. (7/ e ;t -f /,'v-t*r a
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FM 6.3 Exhibit 10 page 1 of 1 Supporting Document for Data Request #205 (Grease injection at 85 psi while tendon sleeves can handle 10 psi) It was reported in the dome delamination report that tendon grease was injected at up to 85 psi. The Requirement Outline for the tendon sleeves (RO-3040) identifies the ability of the sleeves to handle a hydrostatic pressure of 10 psig without leaking water as a performance requirement. This appears to be a discrepancy, especially considering that the hydrostatic pressure in the vertical tendon sleeves will exceed 10 psig due to the column of grease that normally exists. This evaluation will determine if the tendon sleeves could reasonably accommodate the reported injection pressure without failure. The vertical tendons extend from elevation 80'-6" to 267'-6" per Prescon Drawings 5EX-003-P-03 and 5EX-003-P-40. The total elevation change is 187'. The tendon grease is Visconorust 2090P-4. Per the MSDS, the specific gravity is 0.885. The density of the grease is 0.885
- 62.4 lb/ft 3 = 55.2 lb/ft3 . The pressure at the bottom of the tendon sleeve is therefore 55.2 lb/ft3
- 1 ft 2/144 in2 = 0.384 psi per foot of elevation of grease. For a full tendon sleeve, the pressure is 187 ft
- 0.384 psi/ft = 72 psi.
The tendon sleeves are either a rigid or flexible type. From a pressure retaining standpoint, the thinner-wall flexible sleeves are more limiting. From RO-3040, the flexible sleeves are 5-1/4" OD, minimum 22 gauge (0.028) corrugated galvanized steel. The equation for minimum wall thickness from USAS B31.1 can be used to determine the pressure capability of the sleeves: P = [2*5*E*tm]/[DO-2*y*tm] Where S = maximum allowable stress, 10,600 psi E = joint efficiency, 0.82 tm = minimum wall thickness, 0.028 in Do = outside diameter, 5.25 in y = constant, 0.4 for temperatures below 900F P = [2*10,600*0.8*0.028]/[5.25-2*0.4*0.028] P = 91 psig internal pressure The above calculation shows that the tendon sleeves could handle the reported injection pressure as well as the normal hydrostatic pressure, even when considering conservative material and joint efficiency properties. When considering more realistic properties and the safety factor inherent in the allowable stress value, there exists considerable margin in the sleeve material. Prepared by Craig Miller 1/09/10 1 Tendon sleeve material is unknown. The minimum allowable stress for non-butt welded carbon steel, as given in Table A-1 of B31.1, is 10,600 psi at 200F. 2 B31.1 lists joint efficiency from 0.80 to 1.0 for various longitudinal welds (excluding furnace butt welds, which would not be practical for corrugated pipes). The lowest value of 0.80 is selected for conservatism.
FM 6.3 Exhibit 12 page 1 of 2 CALCULATION SHEET ROUGH ESTIMATE OF THE IMPACT OF TENDON GREASE INJECTION ON CONCRETE TENSILE STRESSES A. DISCUSSION After installation and tensioning of the containment building tendons, hot grease is injected at moderate pressure to seal the void in the tendon conduit. The injection temperature was typically about 140 F with a limit of 200 F, and pressure was typically about 40 psi with a limit of 150 psi. Both temperature and pressure have the potential for producing a tensile load on the concrete surrounding the tendon conduit. This calculation sheet places an upper limit on that potential impact. B. REFERENCED PARAMETERS o Tendon strand diameter: 7mm o # of strands pertendon: 163 o Conduit OD: 5.25" o Conduit wall thickness: 1/16" o Max. grease temperature: 200 F o Max. grease pressure: 150 psi o Assumed linear coefficient of thermal expansion for steel and concrete: 7 E-6 /F o Assumed pressure coefficient for steel and concrete: 30 E6 psi o Assumed concrete ambient temperature: 70 F o Containment wall thickness: 42 in o Conduit/ft = 157 ft/ 94 tendons = 0.60 tendons/ft vertical C. CONDUIT RADIAL EXPANSION DUE TO PRESSURE dR/R = 1/(30 E 6 psi)
- 150 psi = 0.000005 D. CONDUIT RADIAL EXPANSION DUE TO TEMPERATURE dR/R = 7 E-6 /F *(200 F - 70 F) = 0.0009 Cross-sectional area of one strand is 0.06 sq in Total cross-sectional area of 163 strands is 9.7 sq in Total cross-sectional area of conduit is 21.6 sq in Grease fraction is 45%
FM 6.3 Exhibit 12 page 2 of 2 E. CONCRETE TENSILE STRESS DUE TO EXPANDED CONDUIT Conduit expansion pressure is 0.0009
- 30 E6 psi = 27 ksi Expansion force per linear inch of conduit is 27 ksi
- 1/16 in = 1700 lbf/in Average tensile pressure on concrete is 0.60 conduit/ft
- 1 ft/ 12 in *1700 lbf/in = 85 psi F. CONCLUSIONS o Radial expansion due to pressure is negligible relative to temperature o Radial expansion due to temperature (assuming conduit goes immediately to 200F) produces an average concrete tensile stress of 85 psi o The thermal expansion impact is actually significantly less than estimated here since actual outlet temperatures were about 140 F instead of the limit of 200 F and the heat loss that occurredby 45% volume grease surrounded by 55% volume steel strands. Actual stress is more like 20 psi.
By Ray Waldo, PII team
FM 6.3 Exhibit 13 page 1 of 5 I., Systems MX Calc. Sub-Type Priority Code 3 Quality Class Safety-Related NUCLEAR GENERATION GROUP ANALYSIS I CALCULATION S09-0044 (Calculation #) Predicted Tendon Elongations for Restoration of SGR Access Opening (Title including structures, systems,:components) E] BNP UNIT 0 CR3 EIHNP ElRNP LINES REALL APPROVAL E Electronically Approved Rev # Prepared By Reviewed By Supervisor rm- Name Name Amir Mold Chris Sward Chrs Sward Date Date Date q/)'I-/OcI 0_________ OR___14 __1_09 (For Vendor Calculations) Vendor Sargent & Lundy LLC Vendor Document No. N/A Project No. 11550-048 Owner's Review By Date
FM 6.3 Exhibit 13 page 2 of 5 Calculation No. S09-0044 Revision 0 Attachment Page 1 1.0 Purpose The purpose of this calculation is to determine the theoretical (predicted) elongation. of containment post-tensioning tendons that are either to be replaced or re-stressed due to Steam Generator Replacement (SGR). The elongation to be predicted is the immediate elongation that will occur during stressing from an initial force that will remove all slack to the maximum force at 80% of ultimate capacity. A description of the opening in the containment shell, as well'as the tendons to be removed or de-tensioned for the SGR, is described in calculations S06-0002 and S06-0005 (Refs. 4 and 5).
FM 6.3 Exhibit 13 page 3 of 5 Calculation No. S09-0044 Revision 0 Attachment Page 2 2.0 References
- 1) DBD11, Design Basis Document for the Containment, Rev. 6.
- 2) 5EX7-003 P-10A, Rev. 1, Horizontal Tendon Detail, (Prescon).
- 3) 5EX7-003 A-07, Rev. 2, Anchor Detail at Buttress, (Prescon).
- 4) Calculation No. S06-0002, Rev. 1, "Containment Shell Analysis for Steam Generator Replacement - Design Criteria".
- 5) Calculation No. S06-0005, Rev. 1, "Containment Shell Analysis for Steam Generator Replacement - Shell Evaluation During Replacement Activities".
- 6) 5EX7-003 P-2, Rev. 3, Vertical Tendon Placement, (Prescon).
- 7) 5EX7-003 P-3, Rev. 3, Vertical Tendon Placement, (Prescon).
- 8) 5EX7-003 P-4, Rev. 3, Vertical Tendon Placement, (Prescon).
- 9) 5EX7-003 P-15, Rev. 0, Vertical Tendon Placement, (Prescon).
- 10) 5EX7-003 P-16, Rev. 1, Vertical Tendon Placement, (Prescon).
- 11) 5EX7-003 P-17, Rev. 0, Vertical Tendon Placement, (Prescon).
- 12) 5EX7-003 P-33, Rev. 0, Vertical Tendon Placement, (Prescon).
- 13) 5EX7-003 P-34, Rev. 0, Vertical Tendon Placement, (Prescon).
- 14) 5EX7-003 P-35, Rev. 0, Vertical Tendon Placement, (Prescon).
- 15) 5EX7-003 P-40, Rev. 2, Vertical Tendon Placement, (Prescon).
- 16) 5EX7-003 P-41, Rev. 4, Vertical Tendon Placement, (Prescon).
- 17) 5EX7-003 P-21, Rev. 2, Hoop Tendon Placement, (Prescon).
- 18) 5EX7-003 P-22, Rev. 1, Hoop Tendon Placement, (Prescon).
- 19) 5EX7-003 P-23, Rev. 1, Hoop Tendon Placement, (Prescon).
- 20) 5EX7-003 P-27, Rev. 1, Hoop Tendon Placement, (Prescon).
- 21) 5EX7-003 P-28, Rev. 1, Hoop Tendon Placement, (Prescon).
- 22) 5EX7-003 P-29, Rev. 0, Hoop Tendon Placement, (Prescon).
- 23) ACI 318-63, "Building Code Requirements for Structural Concrete".
F - 24) EC 63016, Rev. 5, "Containment Cooling".
FM 6.3 Exhibit 13 page 4 of 5 Calculation No. S09-0044 Revision 0 Attachment Page 3 3.0 Design Inputs The following design inputs are used in this calculation:
" Tendon properties and design parameters from DBD1 1 (Ref. 1):
Curvature friction coefficient, /t,=0.16 Wobble coefficient, K=.0003 Number of tendon wires, n,=163 2 Effective area of tendons, At=9.723 in Tendon ultimate stress, oult=240 ksi
" Modulus of elasticity for carbon steel; E=29000 ksi e Hoop and Vertical tendon layout from Prescon Dwgs. Refs. 2 and 3
" Vertical tendon profile geometry from Prescon Dwgs. Refs. 6-16
" Hnn~p t*-ndnn ,nrnfil. np~nmp~tr frnm Prt_.,nnn 1nwq- Rpfs 17-22
" The initial tendon stress to remove slack to be 360 kips, from EC 63016 (Ref.
24). 4.0 Assumptions There are no unverified assumptions in this evaluation.
FM 6.3 Exhibit 13 Ca~cftrJ48f 19-0044 Rev. 0 Tendon 23V01 E= 29000 ksi Modulus of elasticity of steel wires Ayire= 0.05965 sq in Area of pre-stressing tendon wire (Area of 163 wire tendon=9.723 in 2 , per Pg. 6, DBD11, Ref. 1) 0.16 Curvature friction coefficient, per Pg. 27, DBD1 1 (Ref. 1) K= 0.0003 Wobble coefficient, per Pg. 27, Ref. 1 r= 67.28 ft Radius of vertical tendons about center of containment shell, per Prescon Dwg. P10-A (Ref. 2). n 163 Number of effective wires, per Pg. 6, Ref. 1 and Att. 1 At= 9.72 sq in Effective area of tendon T= 360 kips Initial force in tendon to remove slack Tf= 1867 Ikips 80% of ultimate tendon force (tendon ultimate stress=240 ksi, per Pg. 5, Ref. 1) 1507 kips Net force applied to tendon Point Elevation Azimuth y A0 c d R B EB AL L Tx Tave 6 1 268.00 117.58 1507.00 1A 250.00 117.58 18.00 0.00 0.00 18.00 0 0.00 0.00 18.00 18.00 1498.88 1502.94 1.15 1B 242.54 118.17 7.46 0.58 0.68 7.49 41 0.18 0.18 7.51 25.51 1452.35 1475.62 0.47 1C 235.03 118.75 7.51 0.58 0.69 7.54 41 0.18 0.37 7.55 33.05 1407.02 1429.68 0.46 2 79.67 118.75 155.36 0.00 0.00 155.36 0 0.00 0.37 155.36 188.41 1342.94 1374.98 9.09 Predicted Elongation:I 11.17 in Total Tendon Length= 188.41 ft 6 y Vertical distance between points i and j (ft) nf= 12.08 in A° Circumferential change from point i to j (degrees) RI c Cicumferential distance between points i and j (ft) d Absolute distance between points i and j (d2=c 2 +y2 ), (ft) 1lB'P R Radius of curvature of tendon between points i and j (ft)
'Ci B Angular change between points i and j (radians)
EB Total angular change from tensioning end to point j (radians) AL Length of tendon between points i and j (ft) L Total length of tendon from tensioning end to point j (ft) Tx Force in tendon at point j (kips) Tave Average force in tendon segment between points i and j (kips) 6 Elongation of tendon segment between points i and j (in) 6 jnf Predicted elongation of tendon assuming no friction loss 6nf=To*L 2/(E*At) 2* Tendon Profile Circumferential Angular Change Offset
FM 6.3 Exhibit 14 page 1 of 1 Calculation Wire Elongation Young's Modulus, E 2.90E+07 psi Guaranteed UTS 240 ksi Wire Diameter 0.276 in (7 mm) Wire Area 0.0596 inA2 Force per wire 11,443 psi (80% x 240 ksi x 0.0596 inA2) Wire length 2,256 in (188 ft for vertical tendons) Elongation, A=FL/AE 14.94 in Correction for 360 kips Tendon force 80% GUTS 1,865,242 lbs (11,443 psi x 163 wires) Reduced tendon force 1,505,242 lbs (1,865 kips - 360 kips) Reduced percentage 19.30% (1,865 - 1,505) kips / 1,865 kips Reduced elongation 12.05 in (14.94 * (1 - 0.193))
FM 6.3 Exhibit 15 page I of 13 Grease losses from tendon sleeves 25.00 25.00 20.00 20.00 15.00 r i. 15.00 lO.OO 4- 10.00 5.00 4- 1 5.00 0.00 . 7ý71w- 0.00 surv 4 surv 5 surv 6 surv 7 surv 8 Grease Losses (gal) (left axis) --I-Std Dev (right axis) Average and standard deviation of grease losses for each surveillance 2/21/2010 1
FM 6.3 Exhibit 15 page 2 of 13 GREASE REMOVAL AND REPLACEMENT TABLE 4 Crystal River Unit 3 TENDON END GREASE GREASE NET DIFFERENCE : NUMBER DESIGNATION REMOVED REPLACED
-(gals.) (__als.)
12V1 Field + Shop 29.9 34.0 4.1 Gallons 34V4 Filed + Shop 12.9 17.9 5.0 56V2 Field + Shop 89.9 92.9 3.0 D105 Field + Shop 11.0 34.0 23.0 D212 Field + Shop 4.0 16.0 12.0 D328 Field + Shop 8.0 16.0 8.0 13H20 Field + Shop 2.0 21.1 19.1 13H40 Field + Shop 4.0 24.5 20.5
*H26 Field + Shop 2.0 21.1 19.1 51H274 Field + Shop 1.0 5.0 4.0 51H41 Field + Shop 2.0 25.6 23.6 64H19 Field + Shop 2.0 16.8 14.8
- Unsealed in error.
TP420Ads
FM 6.3 Exhibit 15 page 3 of 13 Crystal*River Unit 3 Post-Tensioning System: 5th In-Service Tendon Surveillance Test Report: Revision 0 TABLE 5:
SUMMARY
OF GREASE REMOVAL AND REPLACEMENT TENDON GREASE REMOVED GREASE REPLACED NET (GALLONS) (GALLONS) DIFFERENCE
- 34V6 30 71.5 41.5 56V15 96 116 20 61V14 64 82 18 D215 51 32 D224 38 51 13 D231 40 51 11 35HI 02 22 20 42H1 02 22 20 46H21 04 19 15 46H28 3.5 19 15.5 46H29 07 22 15 46H30 04 17 13 46H47 04 24 20 62H8 02 22 20
- Acceptance Criteria: Net difference shall not exceed 4 gallons. Please refer to the applicable NCR where it is noted that final evaluation and disposition of acceptance criteria is deferred to Gilbert Commonwealth (to be addressed in their engineering report).
17
FM 6.3 Exhibit 15 page 4 of 13 20TH YEAR SURVEILLANCE OF TIlE POST-TENSIONING SYSTEM AT THE Florida CRYSTAL RIVER NUCLEAR PLANT UNIT 3 Power CORPORATION TABLE XII:
SUMMARY
OF DATA SHEETS SQ 12.1 GREASE LOSS Vs GREASE REPLACEMENT TENDON GREASE REMOVED GREASE REPLACED DIFF. NET % SHOP FIELD TOTAL SHOP FIELD TOTAL (GAL.) VOLUME (GAL.) (GAL.) 12VI 2.00 36.75 38.75 40.75 0.75 41.50 +2.75 143.46 1.91 23V2 0.75 9.75 10.50 11.50 0.00 11.50 +1.00 142.52 0.70 61V21 0.75 88.50 89.25 20.25 72.50 92.75 +3.50 144.03 2.43 43V04 0.50 0.00 0.50 7.50 0.00 7.50 +7.00 N/A N/A D113 4.50 4.00 8.50 6.20 3.50 9.70 +1.20 115.11 1.04
-*D 115 4.50 4.50 9.00 7.00 4.00 11.00 +2.00 117.17 1.71 D212 6.50 4.00 10.50 20.00 4.50 24.50 +14.00 115.55 12.12.
D304 12.00 7.25 19.25 38.20 0.00 38.20 +18.95 103.68 18.300 D311 24.00 4.00 28.00 46.50 3.50 50.00 +22.00 115.12 19.10.
- SEE NCR No. FN604-018, 019, 020 t
45
FM 6.3 Exhibit 15 page 5 of 13
) 20Tll YEAR SURVEILLANCE OF THE POST-TENSIONING SYSTEM AT THE Florida K,/'
CRYSTAL RIVER NUCLEAR PLANT UNIT 3 Power CORPORATION TABLE XII:
SUMMARY
OF DATA SHEETS SQ 12.1
.1 GREASE LOSS Vs GREASE REPLACEMENT TENDON GREASE REMOVED GREASE REPLACED DIFF. NET %
SHOP FIELD TOTAL SHOP FIELD TOTAL (GAL.) VOLUME I (GAL.) I_ I_(GAL.) 42H18 3.75 2.00 5.75 5.25 5.25 10.50 +4.75 121.40 3.91 V.' 42H29 3.50 3.25 6.75 5.25 6.25 11.50 +4.75 121.48 3.91 42H30 3.00 3.00 6.00 7.00 7.00 14.00 +8.00 121.59 6.58. 42H31 2.50 3.00 5.50 5.25 5.75 11.00 +5.50 121.84 4.51 42H32 3.75 2.50 6.25 6.25 4.75 11.00 +4.75 121.36 3.90 421-133 3.00 3.00 6.00 6.25 4.75 11.00 +5.00 120.38 4.15 42H34 3.00 3.00 6.00 6.50 6.25 12.75 +6.75 121.99 5.53
- 42H35 3.25 4.50 7.75 4.90 5.30 10.20 +2.45 121.27 2.02
"-42H36 4.00 4.00 8.00 4.00 5.75 9.75 +1.75 121.62 1.44 42H37 4.50 4.50 9.00 6.20 5.00 11.20 +2.20 120.44 1.83 42H44 4.75 3.50 8.25 5.30 4.90 10.20 +1.95 121.08 1.61 51H25
- 3.50 3.50 7.00 8.00 4.50 12.50 +5.50 120.73 4.56 51H25
- 3.00 4.00 7.00 4.50 4.00 8.50 +1.50 120.73 1.24 51 H26 4.50 3.75 8.25 5.25 4.50 9.75 +1.50 121.43 1.24 51H27 3.50 3.25 6.75 5.30 5.70 11.00 +4.25 121.60 3.50
.4 'I 511H28
- 3.50 4.00 7.50 4.50 4.75 9.25 +1.75 120.46 1.45 51H28 ** 4.00 4.00 8.00 4.50 4.00 8.50 +0.50 120.46 0.42 I 53H2 53H46 4.50 3.25 4.00 3.50 8.50 6.75 5.75 6.00 6.25 5.25 12.00 11.25
+3.50
+5.25 121.32 121.60 2.88 4.32 621141 4.00 4.00 8.00 7.10 5.30 12.40 +4.40 *121.37 3.63 62H46 3.50 4.50 8.00 6.25 6.50 12.75 +4.75 121.11 3.92 51 H41 N/A 3.50 3.50 N/A 4.00 4.00 +0.50 N/A N/A GREASED 11/18/97
- SEE NCR No. FN604-021 GREASED 12/18/97 46
FM 6.3 Exhibit 15 page 6 of 13 25TH! YEAR SURVEILLANCE OF TIHE POST-TENSIONING SYSTEM AT THE CRYSTAL RIVER NUCLEAR PLANT Florida Power AProgress Energy Company UNIT 3 TABLE XI:
SUMMARY
OF DATA SIIEETS SQ 12.1 GREASE LOSS Vs GREASE REPLACEMENT TENDON GREASE REMOVED GREASE REPLACED DIFF. NET % SHOP FIELD TOTAL SHOP FIELD TOTAL (GAL.) VOLUME (GAL.) (GAL.) 12V01 2.25 105.75 108.00 0.00 115.00 115.00 7.00 139.43 +5.02 12V02 3.00 0.00 3.00 3.50 0.00 3.50 0.50 139.78 +0.36 23V02 2.75 0.00 2.75 4.75 0.00 4.75 2.00 139.85 +1.43 45VI4 7.00 102.50 109.50 0.00 118.50 118.50 9.00 140.34 +6.41 61V08 7.00 102.75 109.75 0.00 112.50 112.50 2.75 139.78 +1.97 461121 3.25 3.25 6.50 3.50 4.00 7.50 1.00 119.96 +0.83 461129 1.75 1.75 3.50 3.50 2.50 6.00 2.50 119.73 +2.09 461130 1.75 1.50 3.25 4.50 2.25 6.75 3.50 119.73 +2.92 K, 461131 1.75 1.75 3.50 3.25 4.50 7.25 3.75 119.73 +3.13 461132 1.75 1.75 3.50 2.25 3.50 5.75 2.25 119.73 +1.88 461133 1.75 1.75 3.50 4.50 3.50 8.00 4.50 119.73 +3.76 461134 1.75 1.75 3.50 2.50 3.50 6.00 2.50 119.73 +2.09 461135 1.75 1.75 3.50 3.50 2.50 6.00 2.50 119.09 +2.10 461-136 2.25 1.00 3.25 2.50 4.50 7.00 3.75 119.25 +3.14 46H37 1.75 1.00 2.75 3.50 4.00 7.50 4.75 119.93 +3.96 461138 1.50 1.50 3.00 2.50 4.00 6.50 3.50 119.73 +2.92 461139 1.75 3.50 5.25 3.00 3.50 6.50 1.25 119.73 +1.04 56H116 2.50 2.00 4.50 3.00 3.50 6.50 2.00 119.53 +1.67 621102 2.25 2.50 4.75 4.50 5.25 9.75 5.00 119.33 +4.19 621-109 3.00 2.00 5.00 3.50 5.25 8.75 3.75 119.73 +3.13 621113 2.50 1.50 4.00 4.75 4.50 9.25 5.25 120.59 +4.53 D126 14.50 25.75 40.25 0.00 42.75 42.75 2.50 115.97 +2.16 D212 24.75 22.00 46.75 0.00 62.25 62.25 15.50 113.86 +13.73 D339 40.00 15.00 55.00 73.75 0.00 73.75 18.75 100.18 +18.72
- ADDRESSED INFN 730-007 ADDRESSED IN FN 750-006 40
I FM 6.3 Exhibit 15 page 7 of 13 I DOCUMENT NUMBER: DOCUMENT TITLE CR-Ni 002-504 REVISION: FINAL REPORT FOR THE 301" YEAR CONTAINMENT IWL INSPECTION 0 PAGE: 45 PROJECT TITLE: 30*" YEAR TENDON SURVEILLANCE AT CRYSTAL RIVER DATE: 01124108 P Eu I 10.2 TENDON CAP RESEALING AND GREASING I 10.2.1 After completion of all inspections, the anchorage components were hand coated with cold grease to ensure complete coverage. The caps were reinstalled with new gaskets and the results of the grease cap replacement were recorded on Data Sheet SQ 12.0 and are summarized in Tables 50 thru 55. I 10.2.2 Upon acceptable cap replacement, the necessary amount of sheathing filler (grease) was added. All of the inspected tendons were refilled within the acceptable limits as stated in the PSC Procedure SQ12.1. The results of the grease replacement were recorded on Data Sheet SO 12.1 and are summarized in Tables 56 thru 60. U 10.2.2.1 The absolute difference between the amount of grease removed/lost and the amount of grease replaced in the subject tendon shall not exceed 10% of the net duct volume per PSC Procedure SQ 12.1. No tendon accepted above 10% of the net duct volume more than was lost, and all refills were acceptable. I I fl0S:J~l -- RBU ýE 'A I Z 0 00 4 0 P. us 4c W W Po
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BT4 IBT 6 YES YES YES YES YES YES YES YES YES YES NO NO YES YES I
I FM 6.3 Exhibit 15 page 8 of 13 I DOCUMENT NUMBER: DOCUMENT TITLE: CR-N1002-504 REVISION: 0 FINAL REPORT FOR THE 30'm YEAR CONTAINMENT IWL INSPECTION PAGE: 46 PROJECT TITLE: 30TM YEAR TENDON SURVEILLANCE AT CRYSTAL RIVER DATE 01124108 I Emuy
- I- I- I !W P~! !- P- I-I
~
"°"1 _*zz-- = ! = = = -=-w° 4- . to---K..- - -
I 5. go 0 ) P w Dosg 041 .I 13H36 BT 1 YES YES YES ' YES YES NO YES 8T 3 YES YES YES YES YES NO YES I 42H146 BT12 BT 4 YES YES YES YES YES YES YES YES YES YES NO NO
" YES YES I 461121 BT 4 BT 6 YES YES YES YES YES YES YES YES YES YES NO NO YES YES BT 1 YES YES YES YES YES NO YES I 51 H34 BT 5 YES YES YES YES YES NO YES BT 2 YES YES YES YES YES NO YES 621H30 I BT 3 YES YES YES YES YES NO YES I * .- ="-..
I I I 13H33 BT 1 T 43 YES YES YES YES YES YES YES YES YES YES NO NO YES YES i 13H34 BT 1 BT3 YES YES YES YES YES YES YES YES YES YES NO NO YES YES ST I YES YES YES YES YES NO YES I 13H35 BT53 BT 2 YES YES YES YES YES YES YES YES YES YES NO NO YES YES 13H37 i 13Q338 BT 3 BT1 YES YES YES YES YES YES YES YES YES YES NO NO YES YES ST 3 YES YES YES YES YES NO YES I I
U FM 6.3 Exhibit 15 page 9 of 13 I DOCUMENT NUMBER: CR-N1002-504 DOCUMENT TITLE: REVISION: FINAL REPORT FOR THE 30'm YEAR CONTAINMENT IWL INSPECTION 0 PAGE: 47 PROJECT TITLE: 30'" YEAR TEINIDON SURVEILLANCE AT CRYSTAL RIVER DATE: 01/24/08 I I -Tk6L(Eqý4r 146f'liý1,04A-GtNýffi§ EJ-w w tVli 2.0 s:cýi5R'ý'ASlýICAýP,ýREFýLrAý.EMEkY 0 0 IL 0 V) w W I wI 10 z w 0w 4KC uo 7-9 z on, W
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In J IL ul 0 co ill 0. a. U, 0 Z I BT 4 YES YES YES YES I I qc YES 0O NO YES 4GH19 U 46H20 8T 6 ST 4 YES YES YES YES YES YES YES YES YES YES NO NO YES YES BT 6 YES YES YES YES YES NO YES I 46H22 ST 4 BT 6 YES YES YES YES YES YES YES YES YES YES NO NO YES YES I 46H23 BT 4 BT 6 YES YES YES YES YES YES YES YES YES YES NO NO YES YES BT 4 YES YES YES YES YES NO YES I 46H24 BT 6 YES YES YES YES YES NO YES I -i -l - I w-I w I liei __ _ I 62H$29 BT 2 BT 6 YES YES YES YES YES YES YES YES YES YES NO NO YES YES I 62H31I BT 2 BT 6 YES YES YES YES YES YES YES YES YES YES NO NO YES YES I 62H32 BT 2 BT 6 YES YES YES YES YES YES YES YES YES YES NO NO YES YES BT12 YES YES YES YES YES NO YES I 62H33 BT 6 BT 2 YES YES YES YES YES YES YES YES YES YES NO NO YES YES I 6234 16 YES YES YES YES YES NO YES I
I FM 6.3 Exhibit 15 page 10 of 13 I DOCUMENT NUMBER; CR-Nl002-504 DOCUMENT TITLE FINAL REPORT FOR THE 30 REVISION- 0 YEAR CONTAINMENT IWL INSPECTION _ PAGE: 48 47 PROJECT TITLE: 3074YEAR TENDON SURVEILLANCE AT CRYSTAL RIVER DATE: 01124108 EgS I I TENDON END (GALLONSI 1GALLONSI
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DIFF. DUCT I 01FIFP VOLUME % ACCEPT A (G... .. O ..s l L (GAL) , AI I 12V01 TOP END 2.5 TOTAL 78.5 END 0 TOTAL 82.19 369 1 %%7 %..p 14397 2.56 YES BOT 76 82.19 I 4SV20 TOP 3 88 0 91.04 3.04 144.47 2.10 YES BOT 85 9I.4 I 61V08 TOP BOT 2.5 52.5 55 708 49.56 5664 1.64 14,12 1.13 YES I 61V17 TOP BOT 2.5 596 98.5 1 1062 107.2 8.7 144.74 8.01 YES I I I I I I I I I I I RETAINED IN HARD COPY
I FM 6.3 Exhibit 15 page 11 of 13 I DOCUMENT NUMBER: CR-N.O02-504 D5 DOCUMENT TITLE: PROJECT TITLE: REVISION: 0 FINAL REPORT FOR THE 30TMYEAR CONTAINMENT IWL INSPECTION 30"'YEAR TENDON SURVEILLANCE AT CRYSTAL RIVER OATE: PAGE: 49 __ 01124108 BMW I I GREASE REMOVED GREASE REPLACED DUCT TENDON END (GALLONS) (GALLONS) DIFF VOLUME ACCEPT TOTAL (GAL.) DIFF. I 13H36 BT 1 END 2.5 TOTAL 5 END 354 7.08 2.08 121.67 1.70 YES BT 3 2.5 354 I 42H46 BT 2 2-5 55 3.09 5.74 0.24 122.57 0.19 YES BT 4 3.0 2.85 I 46H21 BT 4 ST 6 2.5 2.5 5 3.54 3.54 7.08 2.08 12206 1070 YES I 51H34 BT 1 OT 5' 2.5 2.5 5 2,65 3.54 6,19 1.19 120.88 0,98 YES I BT 2 2.5 3.54 62H30 5ý 7.08 2.08 121.75 170 YES BT 6 2.5 3.54 I I ThNON EAUOND ND(GAL GREASE REMOVED (GALONS)N NS) GREASE to !~ LACED DUCT OIFF. VOLUME DUC AC7CEPT END TOTAL END TOTAL (GAL) (GAL.) DFF. I D129 BT 3 135 36,5 0 39.71 3-21 116.41 2.75 YES BT 5 23 39.71 I D212 BT 1 BT 3 2.5 17.5 20 0 23.78 23,78 3.78 115.99 3.25 YES I D238 BT 4 ST 6 62.5 7 69.5 73.34 0 73.34 3.84 10259 3.74 YES I I I I I
I FM 6.3 Exhibit 15 page 12 of 13 I DOCUMENT NUMBER: DOCUMENT TITLE: CR-N1002-504 REVISION: FINAL REPORT FOR THE 30'" YEAR CONTAINMENT IW. INSPECTION 0 PAGE: 50 L PROJECT TITLE: 30'" YEAR TENDON SURVEILLANCE AT CRYSTAL RIVER DATE: W0/24108 BMW I I (GALLONS) (GALLONS) DIFF. DUCT TENDON END .... VOLUME DIFF. ACCEPT I 13H33 BT 1 END 2 TOTAL 4 END 2.65 I TOTAL 53 Itwkt 1.3 (GAL.) 121.57 1.06 YES I 13H34 BT 3 BT 1 2 2 4 2.65 2.65 5.3 1.3 121.25 1.07 YES BT 3 2 2.65 I 13H35 BT 1 ST 3 2 2 4 2.65 2.65 5.3 1.3 121,77 1.06 YES I 13H37 ST 1 BT 3 2 2 4 2.65 2.65 5.3 1.3 12218 1.06 YES I 13H38 BT 1 BT 3 2 2 4 2.65 2.65 5.3 1.3 121.53 1.06 YES ST 4 2 2.21 I 46H19 BT 6 BT 4 2 2 4 2.65 2.65 4.86 0.86 121.25 0.70 YES 46H20 I 4 5.3 1.3 121.37 1.07 YES BT 6 2 2.65 BT 4 2 2.65 46H22 4 5.74 1.74 122.43 1.42 YES U 46H23 BT BT 4 2 2 4 3.09 265 5.3 1.3 122.63 1.06 YES BT 6 2 265 I 46H24 BT 4 BT 6 2 2 4 2,65 3.09 I 5.74 1.74 121.57 1.43 YES I I I I I U
I FM 6.3 Exhibit 15 page 13 of 13 I DOCUMENT NUMBER: DOCUMENT TITLE: CR-N1002-504 REVISION: FINAL REPORT FOR THE 30'" YEAR CONTAINMENT IWtL INSPECTION 0 PAGE: 51 PROJECT TITLE: 30THYEAR TENDON SURVEILLANCE AT CRYSTAL RIVER DATE: 01I24/08 Pgs I I TENDON END GREASE REMOVED (GALLONS) GREASE REPLACED (GALLONS) DIFF. DUCT DUC % 7TEMOOM END L GAL.) VOLUME 01IFF. ACCEPT I 62H29 BT 2 END 2 TOTAL 4 END 2.65 TOTAL 53 13 (GAL.) 121.93 1.06 YES I BT 6 2 2.65 BT 2 2 2.65 62H31 2 2.65 0.65 122.13 0.53 YES BT 6 0 0 I 62H32 BT 2 BT 6 2 0 2 2.65 0 2.65 0.65 121.45 0.53 YES I 62H33 BT 2 BT 6 2 2.5 4.5 2.65 2.65 5.3 080 122.07 0.65 YES I 62H34 BT 2 BT 6 2 2 4 2.65 2.65 53 13 121.47 1.07 YES I I I I I I I S .If a large amount of grease is lost during the inspection, then I grease must be replaced by pressure pumping it back into the tendon duct. I U Hh I AINtL IN tiAhiL t.AurT ze* :e;5 0'}}