ML19221A863

Reg Guide 1.35,Revision 2, Inservice Insp of Ungrouted Tendons in Prestressed Concrete Containment Structures

ML19221A863
Person / Time
Issue date:	01/31/1976
From:	NRC OFFICE OF STANDARDS DEVELOPMENT
To:
References
REGGD-01.035, REGGD-1.035, NUDOCS 7907100149
Download: ML19221A863 (4)

Text

ger, Revision 2 U.S. NUCLEAR REGULATORY COMMISSION January 1976 REGL D TORY GLODE OFFICE OF STANDARDS DEVELOPMENT REGULATORY GUIDE 1.35 INSERVICE INSPECTION OF UNGROUTED TENDONS IN PRESTRESSED CONCRETE CONTAINMEN f STRUCTURES A. INTRODUCTION 90 inverted U tendons' arranged in two famihes of tendons 90' apart and 150 to 150 hoop tendons in the General Iksipi Critenon 53,"Prosisions for Contain.

gimder and dome.

ment Testing and inspection,' of Appendix A," General Design Cntena for Nuclear Power Plants," to 10 CFR Insenice inspection of unpouted wire and strand Part 50, " Licensing of Production and Uttlization tendons of all sizes (up to an ultimate strength of I acihties, requires in part that the reactor containment approximately 1300 tons) and all types should be be designed to permit (1) penodic inspection of all perfonned (e g., tendons with parallel wi es, with one or impor tant are as and (2) an appropnate surveillanm seseral strands, and with different systems of anchors).

propam. This guide desenbes a basis acceptable to the Materials for all components should satisfy the require-NRC staff for deselopmg an appropriate inservice ments of applicable Amenean Society for Testing and inspection and surveillance program for ungrouted ten.

Materials (ASTM) material standards. The inservice in-dons tn prestressed concrete containment structures of spection program should cover the anchor hardware and light water-cooled reactors. The Adsisory Committee on the corrosion-preventmg filier (pease). To the fullest Reactor Safeguards has been consulted concerr.ing this extent practical, it shculd also cove; the ducts that guide and has concurred in the regulatory position.

contain the tendons. Such an inservice inspection pro-pam is necessary because generally there is no perma-B. DISCUSSION nent instrumentation installed in the containment that could continuously monitor its structural behavior.

Inis resision is the result of comments received on Revision 1, June 1974.and additional staff review.

When an inservice inspection progam is being devel-oped the total contamment tendon population should The recommendations of this guide are appbcab!e to be dnided into homogeneous subpoups consisting af

" typical" prestressed concrete containments having a tendons havmg approximately the same probab lity of i

shallow 40mcd rod on cy hndncal walls about 150 feet corrosion and similar functions in the overall structural in diameter, an merall height of about 200 feet, arid the capabihtics and properties of the structure. Thus, for fo!!owmp tendons: approumately 200 in the dome each structure the insenice inspection program should (either tr.ree famihes of tendons 60" apart or two consider separately the groups of sertical, inverted U, tamdies of tendons 90' apart). 200 ve-tical in the wall, hoop, and dome tendons. This will permit a samphng and 500 hoop tendons in the wall. In addition, these base to be established for determming loss of prestress, recommendations are app.icable to containments having the mam duracteristic checked by the inservice inspec-a hemisphencal dome-shaped roof on cyhndrical walls tion progra.n.

ab ou t 150 feet in diameter, an overall height ranging from 200 a 240 feet, and the followmg te+ns 70 to 3 A tenJon, Imth ends of whkh are anshored at the bottom of the base of the o hndrnal w alls and w tmh approumately follow s the configuration of the containment in the vertwal

• Lmes mdwate substantne thanres f rom preuous swue.

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3. Defects that can be found only af ter the tendt. is prestress losses than the rest, this shculd be taken mto detensioned.

account m selectmg sarroles.

The insenice inspection programs outhned m this C. REGULATORY POSITION guide are appheable to all cortamments with ungroated prestressing systems regardless of plant peopaphica:

1. General locallon.

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The prestressing force in a tendon may be checked by E"

1. " "I

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a hitof f or other equivalent tests. One of the mazn prestressed concrete contamment structures:

objectives of the test is to dscover any bnttle, damaged, or broken wues. Any esentual decrease in the pre-stressmg torce is due to the simultaneous interaction of 1.1 1 Prestressed concrete contamments hasmg a shMlow-domed roof on cyhndncal walls about 150 feet seseral t2me-dependent f actors such as:

in diameter, an oserall height of about 200 feet, and the

1. Stress relaution in the wue; following tendons:' approximately 200 in the dome (either three families of tendons 60' apart or two

2. Temperature vanation of the wire; famihes of tendons 90 apart),200 vertical in the wall, and 500 hoop tendons in the wall (herein desipiated

3. Shnnkage, creep, and tempc.ature deformanons in

(" typical") and con c re t e,

1.1.2 Prestressed concrete contamments having a

4. Ihiferential thermal expansion or contraction hemisphencal dome. shaped roof on cybndrical walls between the concrete and the tendon,and about 150 feet in diameter, an overall hei#it ranpng from 200 to 240 feet, and the following tendons: 70 to

5. Reduction in cro s section of the wires, includmg 90 inverted U tendons' ananged in two famihes of possible f racture, due., corrosion.

tenda 90^ apart and 150 to 180 hoop tendons in the cyhnder and dome (herein designated " hemispherical A liftof f test das not separ* the effects of these dome").

fattors, and corrosion, the factor of greatest concern, cannot be isolated. Therefore, tolerance hmits for the 1.2 For containments that differ from these two loss of prestressmg force, including the effects of types, the program described should serve as the basis possible corrosion, should be established, and the inser-for the development of a comparable insenice inspec-vice inspection program should bc onented toward tion program.

determining whether these hnuts are exceeded. Ilouver, it should be noted that only gross detenoration of the 1.3 All containment simetures with ungrouted ten-prestressing system can be detected.

dons should be inspected in accordance with this guide.

However, if it can be shown by the appbtant that Miny hoop tendons are anchored on but tresses identical containment structures are located on one site, paro.dly h(ated inside the auxihary but!dtng adjacent to that no environmental or other dif ferences are apparent, the co-tainment. Since these anchors are not easdy and that they were constructed by the same contractor

.ccessible, especially during operation of the facdity, in the same manner at the same time fcontinuous they present a special problem for hftoff tests. In the construction), every second containment structure need onpnal layout of tendons, this probkm should be only be visually inspected as described in regulatory s;veifically considered. Any architectural treatment or position C.3.

enmonmental protection of the anchors should te removable without damage to the anchor.

1.4 Containments should be designed so that the prestressing anchor hardware is accessible for periodic Defects that an inspector mig,ht uncover dunng visual examination.

mspection of the anchorage assembly should be sepa-rated mto three groups:

1.5 The inservice inspection should be performed I, 3, and 5 years after the initial containment structural

1. Defects that can be fouad when the tendon is in integrity test and every 5 years thereafter.

its normally stressed condition;

2. Defects that can be found only after the tendon is 2

or the purpow of this Fuide, a tendon is defined as a separate F

tensioned to a nigher value than the existing prestressmg conunuous multiwire or multistrand tensioned element anchored force; and at both ends to an end arrhorage assernbh.

1.35 2 1 Fi 1 M

2. Sample Selection sample selec tion. For each inspection, the tendons should again be selected on a random but representative 2.1 Samples f or the inspection at I, 3, and 5 y ears baus so the sample poup wdl shange somewhat each should he selected as follow s:

time. Ilowever, to develop a history and for conelatmg the obsened data, one tendon from each poup msy be 11.1 ' Typical" containments:

Lept unchanged after the imtral selection.

2.1.1.1 Six dome tendons, tw o h>eated m each

3. %sualinspection 60 poup (i e., three famihes of tendons) and randomly distnbuted to pronde representatise samphng, or three Tendon anchorage assembly har dw are (such as hicated m eaa o0' poup (i.e., two femihes of tendons).

beanng plates. stressing washers, slums, wedges, and buttonheads) of all tendons selected as descnbed in 2.1.1.2 Ene vertical tendons, randomly but regulatory position C.2 should be usually examined For representatively distnbuted.

those contamments for which only vnual mspections need be performed, tendons selected as desenbed in 2.1.1.3 Ten hoop tendons randemly but repre.

regulatory pwtion C.2 should be usually examined to sentatnely distnbuted.

the extent pract cal without dismantlmg load bearing

.omponents of the anchorage. The surroundmg coocrete 2.1.2 "llemispheiical dome" contammcnis:

should also be checked usually for mdications of abnormal matenal behanor. The usual exanunstion of 21.2.1 4'i-of the U tendo i population with the concrete should be s<heduled dunng intepated the re; jt rounded oil to the nearest intepal number of leakage testing whde the contamment ts at its maximum tendons, but no less than four.

test pressure.

2.1.2.2 4'I of the hoop tendon population The method used for removmg pease n order to with the result rounded off to the nearest intepal pe rmit sisual exam natmn of the stressing washers, number of tendons, but no less than nine.

shims, wedges, and beanng p'ates should neither increase the effects of conosioa nor damage the steel (for 9-2.2 If the inspections desenbed in reg ilatory posi-in.ta e,

atch it) and should be usable under oper-tion C.2.1 indicate that there are no problems with ating conu. cions.

prestressing tendons in con tainment structures, the samples for the subsequent inspections may be selected

4. Prestress hfonitoring Tests as follow s:

Tendons selected as described in regulatory position 2.2.1 " Typical" containments:

C.2 sb aid be subjected to liftoff or other equisa!ent tests.o monitor loss of prestress dunng each inspection.

2.2.1.1 If there are three dome groups, ene These tests should include the following:

from each poup; if there are two dome pours, one from each dome poup pbs one additional dome tendon 4.1 The simultaneous measure men t of elongation selected at random and jacting force wi'h properly cahbrated jacks. Allow-able elongation 5, jatkmg loads, allowable tolerances, and 2.2.1.2 Three vertical tendons randomly but the effects of mfluences such as temperature should be representatnely distributed.

established prim to the terts.

2.2.1.3 Three hoop tendons randomly but 4.2 The maximt ' test hftoff force should be greater representatively distnbuted.

th an the meimun. insenice prestressing force. Tae liftoff test should mel ide an unloadmg cycle going down 2.2.2 "liemispherical deme" containments:

to essentially compt te + asiomng of the tendon to idenufy broken or da naped wires or strands.

2.2.2.1 2'T of the U tendon population with the result rounded of f to the nearest intcpal number of

5. Tendon 5faterial Tests and Inspections tendons, but no less than two.

5.1 Previously stressed tendon wires or strands from 2.2.2.2 27 of the hoon tendon population one tendon of each type (i.e., for "typnal" contain-with the result rounded off to the nearest in tegral ments, one dome, one vertical, and one hoop tendon; for number of tendons, but no less than three.

" hemispherical dome" containments, on< U tendon and 9-one hoop tendon) should be removed for testmg and 2.3 If some tendohs are subject to peater prestress examination over the entire length to determine if losses than others, this should be considered in the evidence of corrosion or other deleterious effects is 1.35-3

pre sent. At each successive inspection, the samples 7.3 Failure in die tensi:e test should not occur at a should be selected from different tendons.

strength value less than the guaranteed ultimate strength f the tendon material. Failure below this value in any 5.2 Tensile tests should be made on at least three tendon matenal sample should be considered as onaccep-samples cut from each removed wire or strand (one at table' each end and one at mid lenph; the samples should be the maximum length practical for testing). If frequent

8. Reporting to the Commission stress cychng is suspected, tests simulating diis condition aptana dtena of reguMory pauon O should be conducted. Smularly, where the inservice are n t met or if abnormal matenal behavior is detected inspection program indicates the possibility of a poten-described in regulatory positions C.3 and C.6, a as tially corrosise atmosphere, accelerated corrosion tests p ssible abnormal degradation of the containment struc-should be made.

ture (a boundary desipled to contain radioactise mate-

6. Inspection of Filler Grease rials) is mdicated. Such an occurren ce should be reported to the Commission.' The report should include The method used for checking the presence of description of the tendon condition, the condition of sheathing filler grease should account for (1) the the concrete (especially at tendon anchorages), the nunimum grease coverage needed for different parts of the anchorage system includmg, for example, button, inspection procedure, the tolerances on cracking, and the measures to be used when tolerances are exceeded.

heads; (2) the influence of temperature variations, especially the lowest temperature hkely to occur between two successise inspections; (3) the procedure D. IMPLEMENTATION used to uncoser possible voids in grease in the trumpet; and (4) requirements imposed by grease specifications, quahtie.ition tests, and.ceptability rolerances.

The purpose of this section is to provide infomiation

7. Acceptance Criteria to appbcants and licensees regarding the NRC staff's plans f r utilizing this regulatory guide.

7.1 The prestress force nicasured for each tendon in the tests desenbed in regulatory position C.4 should be This guide retieets current NRC practice. Therefore, within tne limits predicted for the time of the test.

except in those cases in which the applicant proposes an cceptable alternative method for complying with speci-7.2 There shouhl be no more than one defective lied p rtions of the Commission s regulations,this guide tendon in the total sample population. " one sample will be used by the NRC staffin evaluating construction tendon is defective, an adjacent tend.,i on each side of permit and operating license applications for plants the defectise tendon should also be chec (ed. h both of whose construction permits are docketed after the date these tendons are acceptable as defined in regulatory f publication of the guide.

position C.7.1, the inservice inspection program shouki proaed considenng the single deficiency as unique and acceptable. Ilowever, if either aJpeent tendon is defec-tive or if more than one tendon out of the orignal e rep rt to the Commission should be made in accordance with the reportmg program summanzed in Regulatory Guide sample population is defective, the occurrence should be 1.16 "Reporung of Operatmg informahon A ppenda A considered as unacceptable.

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