ML20081H961

Assessment of Applicability of Board Notification 82-105A Re Piping & Pipe Supports.Certificate of Svc Encl

ML20081H961
Person / Time
Site:	Comanche Peak
Issue date:	11/04/1983
From:	Ellis J Citizens Association for Sound Energy
To:
Shared Package
ML20081H953	List: ML20081H950 ML20081H954 ML20081H961 ML20081H964 ML20081H972 ML20081H996 ML20081J012
References
NUDOCS 8311080224
Download: ML20081H961 (39)

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I 1/4/It's UNITED STATES OF AMERICA EO OgE)C NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BO.V;y igI-7 A11:00 In the Matter of g.cr 4 SEC:'OAlf APPLICATION OF TEXAS UTILITIES ccrJfiINGASE9VD-GENERATING COMPANY, ET AL. FOR Docket Nos. 5'0445 and 50-446 AN OPERATING LICENSE FOR COMANCHE PEAK STEAM ELECTRIC STATION UNITS #1 AND #2

'(CPSES) g CASE'S ASSESSMENT OF APPLICABILITY OF BOARD NOTIFICATION 82-105A TO COMANCHE PEAK STEAM ELECTRIC STATION Pursuant to the Board's directive, CASE (Citizens Association for Sound

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Energy), Intervenor herein, hereby files this, its Assessment of Applicability of Board Notification 82-105A (BN 82-105A) to Comanche Peak Steam Electric Station (CPSES).

Although CASE is primarily addressing BN 82-105A herein as regards its applicability to the concerns raised by CASE witnesses Mark Walsh and Jack Doyle (commonly known as the Walsh/Doyle Allegations), it is obvious 'from the wording throughout this important document that one of its primary con-cerns is that matters important to safety in nuclear power plants should not be addressed in a vacuum. This is consistent with CASE's position through-out these proceedings, although both Applicants and the witnesses testifying on behalf of the NRC Staff (or SIT) in these proceedings have consistently attempted to confine the Board's consideration to very narrow, isolated instances of specific pipe supports, etc., often without giving due con-sideration to the overall impact, or implications of such instances. It is gratifying that the NRC Staff at the national level has now confirmed the correctness of many of the positions set forth by CASE. The Board should apply all applicable portions of BN 82-105A to other matters in litigation in these proceedings.

8311080224 831104 PDR ADOCK 05000445 9 PDR

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I1 INTRODUCTION Perhaps the best introduction to the underlying cause of the problems which are discussed in the Board Notice may be found in the Board Notice itself, on page IV-6:

"The design interface between the piping and pipe clamp is an area often overlooked by piping and support designers particularly when one group is responsible for the piping stress analyses and another group is responsible for the support design (in which the pipe clamp is included). The assumption to ignore the design interface be-tween piping and pipe clamps does not necessarily cause unconserva-tive analysis results. However, when pipe clamps can cause exces-sive pipe stresses, it is important for the piping designers to be aware of and able to recognize and evaluate the consequences. When the design interface lacks proper and adequate design procedures to identify those conditions where pipe clamps can significantly affect piping stresses, the likelihood of underestimates of interactive forces, moments, and stresses can occur without due consideration."

The interactive effect also results in forces, moments, stresses, and deflec-tions in the clamp assembly which render the assumptions by the support designer unconservative by a wide margin as well.

SECTION 1 Criteria for Design As relates to the cinched-up "U"-bolt as utilized on a large number of piping systems at Comanche Peak Steam Electric Station, Board Notification 82-105A, September 29,1983(DocketNo. 50-275/323,341,483) contains a quantity of relevant information. The following presentation will outline the relevant material with the Board Notice and compare this material with the positions of CASE, the Staff and the Applicant as contained in the various documents of the operating licensing hearings (i.e., pleadings, transcripts, inspection reports, findings of fact, etc.). The purpose of this comparison is to de-tennine the adequacy of the "U"-bolts as used at CPSES as relates to analytical

I-2 procedures.

The Board Notice covers as a major item the code and legal requirements for inclusion of consideration of the interaction between pipe and clamp. See Section III wh.'ch, in part, is as follows (beginning on page III-1):

"Although no requirements have been written to specifically address the interaction between piping and clamps, several federal and in-dustr/ code requirements which are pertinent to the issue are worth mentioning in this section. . ."

" Appendix A to 10 CFR Part 50 stipulates the General Design Criteria (GDC) for nuclear power plants. The requirements of the General Design Criteria 1, 2, 4,14, and 15 as it pertains to the interaction between piping and pipe clamps are as follows:

" Criterion 1 - Quality standards and records. Structures, systems, and components important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the im-portance of the safety functions to be performed. Where generally recognized codes and standards are used, they shall be indentified and evaluated to determine their applicability, adequacy, and sufficiency and shall be sup)lemented or modified as necessary to assure a quality product in (eeping with the required safety func-tion. A quality assurance program shall be established and imple-mented in order to provide adequate assurance that these structures, systems, and components will satisfactorily perform their safety functions. Appropriate records of the design, fabrication, erec-tion, and testing of structures, systems, and components important to safety shall be maintained by or under the contrcl of the nuclear power unit licensee throughout the life of the unit." (Emphasis added.)

• Criterion 2 - Design bases for protection against natural phenomena.

Structures, systems, and components important to safety shall be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without loss of capability to perform their safety functions. The design bases for these structures, systems, and components shall reflect: (1) Appropriate consideration of the most severe of the natural phenomena that have been historically reported for the site and surr,ounding area, with sufficient margin for the limited accuracy, quantity, and period of time in which the historical data have been accumulated, (2) appropriate combinations of the effects of normal and accident conditions with the effects of the natural phenomena and (3) the importance of the safety functions to be performed.

• Criterion 4 - Environmental and missile design bases. Structures, systems, and components important to safety shall be designed to accommodate the effects of and to be compatible with the environmental conditions associated with normal operation, maintenance, testing, and postulated accidents, including loss-of-coolant accidents. These

I-3 structures, systems, and components shall be appropriately protected against dynamic effects, including the effects of missiles, pipe whipping, and discharging fluids, that may result from equipment failures and from events and conditions outside the nuclear power unit.

Criterion 14 - Reactor coolant pressure boundary. The reactor coolant pressure boundary shall be designed, fabricated, erected, and tested so as to have an extren'ely low probability of abnormal leakage, of rapidly propagating failure, and of gross rupture.

Criterion 15 - Reactor coolant system design. The reactor coolant system and associated auxiliary, control, and protection systems shall be designed with sufficient margin to assure that the design conditions of the reactor coolant pressure boundary are not exceeded during any condition of normal operation, including anticipated operational occurrences.

" Appendix B to 10 CFR Part 50 requires that measures be established to assure that applicable regulatory requirements and design basis for those components important to safety are correctly translated into specifications, drawings, procedures, and instructions. (Emphasisadded.)

Furthermore, Appendix B requires that design measures shall be established for identification and control of design interfaces and for coordination among participating design organizations.

dStandard Review Plan (NUREG-0800)

In Section 3.9.3 including Appendix A of the Standard Review Plan (NUREG-0800)

Revision 1 dated July 1981, the staff position on the stress limits for ASME l - Class 1, 2, and 3 components under specified loading combinations is presented.

The following are excerpts from Appendix A:

dDesign Considerations and Design Loadings I "ASMf. Code Class 1, 2, and 3 components, component supports, and class CS core support structures shall be designed to satisfy the appro-priate subsections of the Code in all respects, including limitations on pressure, and the requirements of this appendix (Appendix A of SRP Section 3.9.3). (Emphasis added.)

Design loadings shall be established in the Design Specification.

The_desian limits of the _acoropriate subsection of the fodfLstall not be exceeded for the design loadings specified. (E@e1/5 aM-)

I -4 a Service Loading Combinations "The identification of individual loads and the appropriate combina-tinn nf thmen inads (i.e... sustained loads, loads due to system operating transients SOT, OBE, SSE, LOCA, DBPB, MS/FWPB and their dynamic effects) shall be in accordance with Section 1.3 (of the SRP Section 3.9.3 Appendix A). The appropriate method of combination of these loads shall be in accordance with NUREG-0484, " Methodology for Combining Dynamic Loads." (Emphasis added.)

" Functional Capability "The design of Class 1, 2, and 3 piping components shall include a functional capability assurance program. This program shall demon-strate that the piping components, as supported, can retain suf-ficient dimensional stability at service conditions so as not to impair the system's functional capability. The program may be based on tests, analysis, or a combination of tests and analysis."

(Emphasis added.)

'8 8. ASME Code Requirements .

"The following excerpts from the ASME Boiler and Pressure Vessel Code,Section III, Subsection N8 (1980 Edition) are applicable to Class 1 piping included in the reactor coolant pressure boundary.

l "NB-3111 states in part:

'The loadings that shall be taken into account in designing a compo-nent include, but are not limited to ... reactions of supporting j

lugs, rings, saddles, or other types of supports.' (Emphasis added.)

• N6-3624.1 states:

.The design of piping systems shall take into account the forces and moments resulting from thermal expansion and contraction, ... and the

restraining effects of hangers, supports, and other localized loadinas.'

! (Emphasis added.)

"NB-3645 states:

%L ugs, brackets, stiffeners, and other attachments may be welded, bolted, or studded to the outside or inside of piping. The effects of attachments in producing thermal stresses, stress concentration, j and restraints on pressure retaining members shall be taken into -

account in checking for compliance with stress criteria.'

"NB-3672.7(d) states:

"Where assumptions are used in calculations ... the likelihood of underestimates of forces, moments, and stresses, including the effects of stress intensification, shall be evaluated.'

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NB-3683.2 states in part:

'The B, C, and K stress indices given herein and in Table NB-3681(a)-1 predict stresses at a weld joint or within the body of a particular product. The stress indices given for ANSI B16.9, ANSI B16.28, MSS SP-48, and MSS SP-87 piping products apply only to seamless products with no connections, attachments, or other extraneous stress raisers on the body thereof.888 The laws, codes and other citations also apply to Class 2 and 3 components with the single exception of NB-3683,2 (which is not a consideration for either Class 2 or 3 as far as we can discern). The ASME citations listed in the Board Notice are all listed under Subsection NB. (The same citations may also be found in Subsections NC and ND.) One variation in the numerical portion of the citations may be noted in the conversion of Subsection NB 3672.7(d) to the per-tinent section of Subsection NC (Class 2) where the subsection may be faund as NC 3673.2,-basic " Assumptions and Requirements" (as least in the 1983 edition)

(d) from Subsection NC reads as follows:

"(d) Where simplifying assumptions are used in calculations or model tests, the likelihood of underestimates of forces, moments, and stresses, including the effects of stress intensification, shall be evaluated."

In any event, the same rules, laws, codes (under different subsections) also apply to the design and analysis for Class 2 and Class 3 components, to insure the health and safety of the public.

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II - 1 SECTION II Positions on Board Notice: CASE, Staff, and Applicant The Board Notice covers the " area of review" under Section IV of the notice.

Excerpts from Section IV will be cited in conjunction with coninentary from the CPSES operating license hearings which relate to the Board Notice where appli-cable.

From the Board Notice at IV-1, the following statement sums up CASE's ar-guements at the hearings:"... it is important for one to keep in perspective the interaction between the piping and pipe clamp because of the potential effect of the clamp on the piping pressure integrity." In reference to the various clamp effects, the Notice states at IV-1:

"It should be noted that different types of pipe clamps can induce various categories of stress (e.g. , primary, secondary, or peak) into the pipe. The predominant component of stress in the pipe wall (e.g., membrane, bending, or shear) can also vary with the different types of pipe clamps. As a result, the predominant loading (e.g., pressure, thermal, dynamic) induced on the pipe from one type of clamp is not necessarily a significant pipe loading for another type of clamp."

A feature of interaction not covered by CASE in the operating licensing hearings is the effect of pipe internal pressure restrictions on the interaction

! between pipe and clamp, but CASE concurs that this is another of the cumulative loads that is not considered in the analysis at CPSES of pipe and clamp design.

The pressure effect element of combined local loading is covered in the Notice l

! at IV-2:

II - 2 "The piping internal pressure results in a radial expansion of the pipe dia-meter. The effect of a pipe clamp will'be a restriction of the outward pipe radial expansion. Althouah the circumferential hnnn ctress could decreae.o when the clamp induces an evenly distributed radial load on the nice, the longitudinal bending and membrane stresses could increase significantly depending on the clamp stiffness relative to the pipe." (Emphasis added.)

In reference to this statement in the Board Notice, CASE would point out that such a problem, when added to thermal constraint, would pose a significant prob-lem in the case of the box-beam type of clamping that has a zero-inch clearance.

The thermal portion of this problem was addressed by CASE in Mr. Doyle's Supple-mental Surrebuttal Testimony (CASE Exhibit 763), on pages 14 and 15. This testi- -

mony includes the following:

"In reference to the box frames (last paragraph, page 33 of SIT Report),

the SIT noted that the expansion in four directions would be about .008 inch and stated that stresses due to such expansion would be negligible.

The box structure around the pipe is a continuous frame. Any load on one member creates fixed-end moments which relative to the stiffness characteristics are distributed around the frame. However, when loads of equal magnitude are placed at similar points on the four members, the distribution balances and each member acts as a fixed ended beam.

To deflect a TS 6 x 4 x 1/2 tube 24 inches long with fixed ends (see CASE Exhibit 6698, items 4I, 4J, 4K, and 4L) .004 (considering that the pipe takes the other .004) takes a con for example, .004(192)(278900000)(17.6)/24giderable equals 27,280 lbs. Seeequivalent force AISC 2-203 (we have deflection solved for "P"). See CASE Exhibit 763G.

Is this 14-ton force insignificant? (Obviously, because of stiffness differentials the pipe will see most of the actual force, but this indi-cates the magnitude of the problem.")

The Board Notice addresses thermal effects at great length from IV-2 through IV-4. This statement occurs at IV-2 regarding the increase in thermal gradient which occurs due to pipe clamp interaction:1 "It should be noted that in light water reactors, the thermal transients are not expected to be as severe as in breeder reactors. However, the presence of metal pipe clamps directly against the outside surface of the piping can cause an increase in the through wall temperature gradient. The increase is due to the thermal interaction between the clamp and the piping."

i Although this was not addressed by CASE in the hearings, CASE agrees that it will have additive effects on those items covered by CASE.

II- 3 The following statement from the Notice (which follows the statement ' quoted above), however, has received extensive coverage by CASE, the Staff and the Applicant:

" Additionally, the differential metal temperatures between the pipe and the clamp will result in differential expansion in the pipe and clamps during thermal transient occurrences."

CASE summarized its concerns relative to the thennal differential problems in its Findings of Facts, in Section IV. The following quotations from Section IV of that document are from pages 1, 2, and 3:

"The tightening of the U-bolt that results in no clearance for expansion of the pipe (cinching up of the U-bolt) was first brought to the attention of the NRC Staff and the Licensing Board through the deposition of Jack Doyle (later accepted as part of his prefiled testimony, CASE Exhibit 669, pages 201, 202, 206 through 213). As will be discussed below, the cinching up of U-bolts induces stress, unaccounted for in the bolt, due to thermal expansion of the pipe and initial stress due to preloading (tightening of the nut to the U-bolt). ,

"The Applicants have stated that the ASME Code does not prohibit the use of cinched-up U-bolts (see Applicants' Exhibit 142F, page 5, Question and Answer No. 17 by Mr. Reedy). Dr. Chang carries this one step further by altering the second law of thennodynamics and the Fourier equations for l

thermal transport -- both basic principles -- (see Applicants' Exhibit 142F, page 5 Question and Answer No.15) when he states that the temperature of the U-bolt and the pipe are the same (this in spite of the fact that only one point is in contact with the pipe and most of the U-bolts are either embedded in the insulation or outside of the insulation). In addition, this is in direct l

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II - 4 contradiction to a test report prepared by ITT Grinnel (CASE Exhibit 669B, Attachment to Doyle Deposition / Testimony, pages 13F through 13J).

"Mr. Finneran, on the other hand, sticks with the maiiana doctrine (never do today what you can put off till tomorrow) by stating if it's no good now, we'll catch it later (see Applicants' Exhibit 142F, page 5, Question and Answer No.16). But clearance for themal expansion is a documented require-ment -- see Staff Exhibit 201, Supplement No. 2. Clearances, page 2 of 2 NRC mandate for radial expansion provisions, and CASE Exhibit 721, page 1 of 15 Clearances, paragraph 2.2. (this is the Comanche Peak provision for radial expansion), and ASME Section NF-3127 " Provisions for Movement of Supported Piping or Components" (CASE Exhibit 659B, Attachment to Walsh Testimony), and NF-3272.1 " Anchors, Guides, Pivots and Restraints" (CASE

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Exhibit 710).

• CASE has submitted a series of documents (see CASE Exhibit 669B, items 13E through 13J) which show the effect of themal transport for components which are in contact with the pipe for 360 degrees of the pipe periphery, after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at a given temperature. The temperature gradients therefore indicate less differential than would be the case of a system as shown in CASE Exhibit 669B, items 13S,13KK,13RR,13XX,13AA,13V,13-00,13VV, 13DDD,13FFF and very many others which transfer heat by point contact or across an air gap.

"The fact of. temperature differentials of significant magnitude between a member in contact with the pipe and a point on this same member some 4 inches away from the contact point may be noted in CASE Exhibit 669B, item 13H. This differential amounts to about 25% of the original contact temperature. On CASE Exhibit 669B item 13F, although there is 360 0 contact with the pipe, It is obvious, the temperature differential between point 1 and point 6 is 15%.

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TI - 5 therefore, that contrary to the claims made by the Applicants, the temperature differential is not insignificant and must be addressed if the system is to be considered safe for use in a nuclear power plant. (See CASE Exhibit 669, pages 201/11-25, 202/1-15; 206/17-25, 207/1-25; 208/1-25; 209/1-25; 210/1-25; 211/1-25; 212/1-25; and 213/1.)"

The SIT had the following comment in reference to temperature differentials on pipe / clamp assemblies. (The comment appeared on page 33 of the SIT report.):

" . . . Alternatively, since the maximum temperature differential between the U-bolt and pipe in uninsulated piping is expected to be less than 50 degress Fahrenheit, calculations performed by the Special Inspection Team indicated that the associated secondary stresses and loads are negligible relative to the ASME Code allowables."

(Emphasis added.)

(CASE, it should be noted, has never seen the calculations referred to in the statement quoted above.)

In reference to U-bolts on insulated pipes, the Applicant made the follow-ing statement in their prefiled testimony (Applicant's Exhibit 142) on page 5:

"Q15. What is your opinion of Mr. Doyle's concern relative to the thermal effects on the pipe and the U-Bolts when U-Bolts have been cinched down on the pipe?

"A15. (Chang) The pipe and the U-Bolt are essentially at the same temperature and consequently any restraining stress on the pipe or thermal expansion stress in the U-Bolt would be negligible. In addition, years of practical experience with U-Bolts in these applica-tions have demonstrated that consideration of such effects is insig-nificant and unwarranted."

The attitude of both the Applicants and those testifying for the NRC Staff

• in these proceedings is obviously in line with the attitude of many others in the

~ nuclear industry, as was discovered by the NRC Staff at the national level during their compilation of this Board Notification.

It should be noted, however, that this Board Notification does not discount thennal' effects on the pipe / clamp assembly, for they made the following state-

• When used in this pleading, "NRC Staff" normally will refer to those testifying for the NRC Staff in these proceedings (the SIT).

i

II - 6 ment at IV-3 of the Notice:

"The themal stresses resulting from differential themal expansion of the pipe and clamp should be categorized as a secondary (membrane and/or bending) stress."

In addition, the Board Notice carries the problem of thermal differentials one step furthe.r (as noted above) in the area involving the variation of the thermal gradient. This point was expanded in the Board Notice at IV-3 where it states:

"In a paper by Chang and Lien 21 it was concluded that the effects of the support clamp on temperature induced peak stresses of thick-walled pipe (schedule 160) due to fast thermal transients are insignificant (increase of 3%). However, the effect of the clamp on the through-wall gradient of an upramp transient increased the secondary stresses per NB-3653 Equation 10 (which included the AT 1 term) by 14L It was also found that thermal discontinuity stress, measured by the difference of the pipe wall average temperature between each side of the edge of the clamp, could be major for thin-walled pipe on slow transients at a location with material discontinuity'.' (Footnote omitted.)

Of more significance in relation to CPSES is the continuation of this statement on page IV-4 of the Notice which states:

"In the Jones and Hamel paper another important result was found when a preload was applied to the clamp. It was shown that if the clamp were preloaded against the pipe, that even a moderate thermal up-transient will result in enough differential thermal expansion to cause the clamp (or pipe) to yield."

In the case of CPSES, the preload is an unknown quantity. The positions of the parties on the problems associated with the combined problems of local loading on the pipe /U-bolt may best be noted from the statements made by CASE, the NRC Staff and the Applicant.

CASE addressed the problem in Section IV-8 of its FinJings of Fact, where it states:

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" The problem associated with cinching up the U-bolts is that this estab-lishes three mechanisms for inducing stress into the pipe wall and the U-bolt instead of the one which was anticipated. The original mechanism which was anticipated was the loads as listed in the output from the pipe stress run (the original design load). The two additional inechanisms are: (1) the stress induced into the U-bolt and the pipe by the torquing of the nuts to cinch up the U-bolt; and (2) the stress resulting from heating of the piping system (radial expansion) which, regardless of how little, will result in a differential temperature between the pipe and the U-bolt with a subst-quent tension induced on the U-bolt, a compression on the pipe, and some bending in the member which restrains the U-bolt.

"The stresses and displacement for the U-bolt, pipe, and involved structures are therefore dependent on the three mechanism involved -- not merely the loading as listed by the Pipe Stress Group (the original design load)."

CASE expanded on this point in its Findings of Fact at Section IV, page 6, where it states:

n0ne major point overlooked by the Applicants in regard to the U-bolt problem is the local problem of the U-bolt itself. In this regard, there l are two major concerns. First is the displacement of the U-bolt, which is additive to the other displacements, the total of which are not allowed to exceed 1/16 inch (see tr. 5132/25,5133/1-25,5134/1-4; CASE Exhibit 669, pages 195/5-25,196/1-25,197/1-19). The second problem to be found in using U -bolts is the induced load to the pipe which must be addressed per NB-3645, 1

l NC-3645, and NF-3121 of ASME and the potential for yielding or at a minimum l

overstressing the U-bolt beyond the limits established by the manufacturer l

in his NRC-approved LD5 (Load Data Sheet). In the case of yielding, should

II - 8 the pipe temperature drop, the clamp would be looser than originally established and would allow for clamp rotation, which by definition is instability (see CASE Exhibit 669B, items 13X,12H,12J.12L,130,13V,13KK, etc., etc.; -

CASE Exhibit 669, pages 317/8-25, 318/1-25, 319/1-25, 320/1-25, 321/1-22)." s Initially, the NRC staff appeared to concur in the requirements as stated by CASE, when they attended the September,1982 hearings. CASE would refer the Board to CASE's Findings of Fact,Section IV, pages 6 and 7, where it states the Staff's position at that time:

"For this particular error in engineering, the Code is specific in more than one citation (see tr. 5333 through 5341; NRC Staff Exhibit 201, Staff rebuttal, page 6, Answer No.10; and page 7, Answer 11, Dr.

Chenconcurring). 'These Code Sections require that stresses in the pipe wall resulting from any attachments be considered.' ASME Code Section III, articles NB-3645, NC-3645, NF-3276, and ND-3645. Beyond this, Code Section NB-3613.3 Mechanical Strength again reinforces this rule, as does NB-3624.1 (see CASE Exhibit 669, page 188/7-18)."

However, during the May,1983 hearings, the NRC Staff backed off from its original position. The following is from CASE's Findings of Facts,Section IV, page 7:

" But during the operating license hearings, Dr. Chen stated that they were written off by engineering judgement (tr. 6742/13-24):

'MR. WALSH: Have the stresses, due to the pretensioning of the bolts, been added to the nomal upset design loads from the pipe as well as the radial expansion of the pipe?

' JUDGE BLOCH: First, is that addressed in the SIT Report?

' WITNESS CHEN: As far as the load combination -- the addition of stresses that Mr. Walsh has just identified, no. But I believe that an assessment was made of the stresses resulting from preloading were made, or was made, and was written off on the basis of engineering judgment and usual industry practice.' (Emphasis added.) "

i II - 9

" The SIT further persisted in their defense of Applicants' procedures with the following statement from Pages 32 and 33 of the SIT Report:

'With respect to the constraint of differential themal expansion aspects of itens 3(a) and 3(b) in the third of Mr. Doyle's concerns, the Special Inspection Team would note that differential themal expansion effects are limited to the case of uninsulated piping. In the case of insulated piping (e.g., main steam, feedwater, and residual heat removal piping),

the temperature differences between the U-bolt and the pipe will be negli-gible because the U-bolt is in themal contact with the pipe and the insulation is installed over both the U-bolt and the pipe. A review of the design temperatures and pipe sizes of uninsulated piping by the Special Inspection Tean indicated that the maximum radial growth of the piping is expected to be less than 1/32 inch. Since the U-bolt is in contact with the pipe and will heat up to some extent, a maximum differential radial growth between the U-bolt and the pipe of about 1/64 inch seems reasonable.

Assuming the U-bolt is as stiff as the pipe, the effective maximum radial constraint will be in the order of 1/128 inch (0.008 inch). Since the U-bolt stresses and pipe stresses associated with 1/128 inch radial con-straint are negligible, differential themal expansion effects in unin-sulated piping are negligible. Alternately, since the maximum temperature differential between the U-bolt and pipe in uninsulated piping is expected to be less than 50 degrees Fahrenheit, calculations perfomed by the Special Inspection Team indicated that the associated secondary stresses and loads are negligible relative to ASME Code allowables. Further, the U-bolt is nomally provided with a 1/16 inch diametrical gap on the pipe to facilitate its installation. Even after cinching down, there is not full circumferential contact between the U-bolt and the pipe. This will also alleviate differential themal expansion effects. The Special Inspection Team concluded that the differential thermal expansion aspects of Mr. Doyle's concern are resolved.'

• The SIT (at page 33) also assumed they addressed the problem of constraint in the case of box frames with this statement:

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.The Special Inspection Team would note that Mr. Doyle also expressed a similar concern regarding differential themal expansion effects in box frame supports with zero clearances. Relative to this concern the Special Inspection Team understood through initial discussions with relevant cognizant engineers that it was an undocumented Gibbs &

Hill desian reconsnendation, where U-bolts or box frames are in direct l

! contact with the supported pipe, that clearances be provided between the U-bolts or box frames and the supported pipe only if the diametri-cal growth of the pipe exceeds 1/32 inch at design temperatures. The Special Inspection Team detemined that of the three pipe support design i groups (PSE, ITT-Grinnell and NPSI) only ITT-Grinnell has documented l guidelines which incorporate the Gibbs & Hill reconinendation. The Special Inspection Team was informed that the two remaining groups also follow the ITT-Grinnell guidelines. In subsequent di.scussions with the Appli-cant, the Special Inspection Team was informed that the above 1/32-inch I

1 t II - 10 l design guideline was applicable only to box frames. It was not applied to U-bolts. For the reasons discussed above the Special Inspection Team agrees that such a design guideline is not needed for U-bolts.'

.(Emphasis added.)

" CASE's response to these argments may be noted, in part, in the 5/4/83 Surrebuttal Testimony of Mr. Doyle (CASE Exhibit 763), at page 11:

"Besides other problems, the U-bolt has two additional features which offer problems: (1) Local deflection due to the weak curved BM which is not in 1800 contact with the pipe; and (2) local stress in the pipe due to point contact. This could result in plastic deformation.

"The stress levels in the pressure boundary as a result could be excessive due to point loading. See CASE Exhibit 669, pages 195/5-25,196/1-21, 197/13-19, and 319/1-11. This must be considered in order to comply with the provisions of ASME Code sections NB-3645, NC-3645, and NF-3127; see also NB-3613.3 and NC-3600.' -

"In further response to the weakness in the SIT argments of no themal problems in the constraint by "U" bolts and box frames, CASE Exhibit 763 again responds at Pages 13 and 14 of the b/4/83 Surrebuttal of Mr. Doyle:

! 'This is nonsense. In my deposition / testimony (CASE Exhibit 669B, items

. 13E through 13J), I submitted test data which (although the temperature range is 9000F, the temperature is a constant in the equation, with a minor variation in the coefficient of thermal expansion, or CTE) indi-cates a minimum of 15% variation overall between the Figure 244 clamp (3600 contact) and the pipe. At PT 2 (direct contact point of clamp) outside diameter, differential equals 3.5%, at PT. 4 (tangency PT. of I pipe and clamp) approximate differential is as little as 10% using this l value. This would still mean the differential thermal expansion is about i 20 thousandths of an inch (and the resistance factor for 9000 insulation l is better than 6000 insulation).

"The drop in temperature for metal in direct contact with the pipe and insulation may best be noted in CASE Exhibit 669B, item 13H. Four inches from the pipe, the temperature has dropped 25%. The U-bolt on the main steam loses contact (optimum) at the horizontal tan. pt.; therefore,

! at a minimtsn,16 inches of the U-bolt is not in contact with the pipe.

What are the stresses in the pipe and U-bolt which resist this force?

In the NRC Staff's rebuttal testimony in the September 1982 hearings (NRC Staff Exhibit 201), Mr. Tapia stated, in Answer 10 on page 6, that effects induced in the pipe wall by a support must be included with the effects derived from pipe stress run. The question as to what the stresses in the pipe and U-bolt are which resist the force was not answered by the SIT, and if the NRC ever answers the question they must keep in mind that these stresses are additive with the pre-tension stresses caused by torquing and all of this is additive with the design load stresses.'

II - 11 "We may add that (continuing from CASE Exhibit 763):

'A second category of instability is created by using 'U' bolts cinched up to the pipe. In this class of failure the mechanism for instability is introduced by heating up the line. Because there is no place for the radial expansion to go (no gap two sides), the 'U' bolt or the pipe is forced to yield; see CASE Exhibit 669B" (sic - should be 669, Doyle deposition / testimony) "pages 318/11-25, 319/1-25, 320/1-25, 321/1-22.

Since the operational life of the plant presents many cycles of heating and cooling of the lines, there will be times when the line is cool that this yielded 'U' bolt or pipe will result in a capability of the clamp to rotate (instability).

8When an unstable clamp fails, this introduces a major change in the fundamental frequency of the piping system, in addition to transferring tne load assigned to the unstable support up and down stream. So the effect of failing a support is compounded The Board Notice continues with the following coninents on the additive effects of dynamic loading to the calculated (pipe stress analysis) loadings.

This material appears at IV-4 of the Notice:

"The dynamic interaction between the pipe and pipe clamp is a complex design problem. From a design standpoint, there are many uncertainties that could affect the actual system response such as consideration of total support sys-tem flexibility, mechanical non-linearities, construction and installation tolerances, and uncertainties in the dynamic loading itself. It is beyond the scope of this report to discuss the clamp-to piping responses to these various factors. However, the report will focus on trose local dynamic effects on the piping that can be attributed primarily to the clamp attachment that, in general, are not explicty evaluated by piping designers.

I l "The computer programs used for piping dynamic analyses generally consider the l pipe as a lumped mass system connected by structural elements with cross-sectional properties equivalent to that of a pipe defined at the center line of the stru.ctural element. Piping supports are modelleo as springs (or infinitely l rigid elements) which are connected to the centerline of the structural elements.

Thus, localized pipe stresses due to clamp pipe interaction are not computed using this lumped mass-spring piping system analytical method. Clamp-induced l

loads on the pipe should be evaluated as a locally distributed or a concen-l trated load on a cylindrical shell using an appropriate method of analysis.

4 II - 12 The resulting local stresses should be added to the stresses calculated by the lumped mass-spring piping model which calculates only beam bending modes.

"During dynamic applied loadings, loc,al pipe stresses induced by the pipe clamp could be significant depending on several factors including clamp to pipe sur-face contact, load magnitude and frequency, and support orientation to pipe." ,

LEmphasis added.)

In reference to the dynamic problems associated with U-bolts and the necessity to combine the loads from all sources, CASE has addressed the point in material appearing previously in this pleading. CASE has also addressed the stiffness problem earlier in this pleading.

The Board Notice contains a final major design connentary which relates to the pretensioning of U-bolts. This is found at IV-5 and reads as follows:

It has recently been established by the staff that certain designs rely on a preload o'f the clamp onto the pipe in order to achieve large stiffness require-ments in the clamp. The large stiffnesses are needed to assure that the clamp will not lift off the pipe during dynamic loadings. When the stiffness require-ments become large, the required preload also becomes large resulting in a radially compressive load on the pipe.

"The resulting local membrane and bending stresses in the pipe due to the preload when properly applied is deflection limited and, thus, self-limiting. Local yielding of the pipe can reduce the preload condition which caused the pipe stress to occur. The preload is a unique situation which should be evaluated f

further because large deformations of the pipe resulting from an initial pre-j load application could be further increased when the piping is brought to hot conditions. In addition, subsequent reapplication of the preload to correct for preload relaxation could cause a ratcheting effect in the pipe wall."

With reference to preloading, the SIT states ( page 32 of SIT Report, NRC Staff Exhibit 207):

II - 13 "Regarding the preloading stresses in item 3(a) of Mr. Doyle's concern, the Special Inspection Team determined that the Brown & Root Design Change Notice (DCN) Number 1, dated 10/8/82, to Construction Procedure No. 35-1195-CPM 9.10 Rev. 8 provides additional requirements to para-graph 3.3.2, ' Threaded Items,' for U-bolts. It states:

'When U-bolts are specified on the design document as not having any clearances, the U-bolt shall be snug tight so that the U-bolt cannot be moved by hand . . .' (ellipsis in SIT original)

' Snug tight is defined as the tightness attained by a few impacts on an impact wrench or the full effort of a man using an ordinary spud wrench.'

"The preloading stresses associated with those procedures are cannon to industry use of threaded fasteners (a proven method of holding structures together), although difficult to assess. In addition, paragraph 4.2.6 of the Construction Procedure requires the following inspection:

'The U-bolt shall be visually inspected by QC for cracks, melted spots and excessive defonnation. Any one of these conditions shall be cause for rejection. This inspection shall be included in the final inspection of the hanger.'

"The Special Inspection Team found this inspection procedure to be sufficient to insure that preloading stresses are within acceptable limits. In subsequent discussions, the Applicant informed the Special

Inspection Team that the U-bolts will be field verified to confirm that they are properly tightened. Further, that the walkdown inspection conducted prior to preoperational testing routinely checks for the proper installation of U-bolts."

CASE responded in the May 4,1983 Surrebuttal Testimony of Mr. Doyle (CASE Exhibit 763, page 11, line 12, through page 12). There it is proved by the use of standard mathematical means that the stresses developed due to the Appli-cant's cinching procedures alone mean that the stress levels will exceed the manufacturer's allowables, as detennined by converting load to stress:

"The SIT neglects to treat the preloading of U-bolts with the respect due. They dismiss the problem by stating that the torque amounts to

'the tightness attained by a few impacts on an impact wrench or the full effort of a man using an ordinary spud wrench.' (SIT Report, page 32, fourth paragraph.) Asstrae the length of a spud wrench to be 10" to the center of pressure exerted by this man. Assume further that this man exerts about 80 lbs. of force. The stress in a 3/4" dia-meter (rod size) U-bolt would be about equal to 80 times .10 divided.by half the thread diameter and this amount divided by the tangent of the sum of the angle of friction and the slope of the thread. For the

\

II - 14 U-bolt in question, the stress in the l' holt would be about (at its ten-sile area of .334) 2580 divided by tan. la degrees (friction angle) plus 30 slope of thread ( (1/thds per inchi/ circumference of root diameter). This. equals 2580 divided by .3046 equals force equals 8472 pounds. Therefore, stress equals 8472 diviced,by tensile area (.334) equals 25366 PSI. How can this be written off when this approach is only a rough cut and not a precise evaluation of the problem -- it indicates very high. stresses and shows a potentially severe problem is present. As a matter of fact, the ITT Grinnel Company has one U-bolt type (B. metallic to overcome expansion (thermal) problems) of clamp which contains a caveat for over-torquing. See CASE Exhibit 763E."

The Applicants did not rebut Mr. Doyle's figures during cross-examination or by the testimony of their rebuttal panel. It should be noted that, the force of 8472 pounds shown in the preceding is greater than the allowable of 5420 pounds for a 3/4 inch diameter rod used as a U-bolt, which is divided between the two legs of the U-bolt (as shown in CASE Exhibit 669B, Attachment to Doyle Deposition / Testimony), page llEE).

In addition (as is noted in the SIT report-see above), neither the NRC Staff nor the Applicant have any idea as to what the preload stresses are,** And further they are not in compliance with GDC provisions which require adequate factors of safety under dynamic conditions (See GDC 2),

In lieu of the above method used by Mr. Doyle, a method prescribed in CASE Exhibit 669B, page 10-0 could be used; i.e. T = K X D X W. Using 800 inch pounds for T. K = .2 as in the example shown in the CASE Exhibit and D = .75 (3/4" bolt as in the CASE Exhibit), the force in the bolt is 800/(.2) X (.75) = 5333 pounds, which is just below the allowable. The above results would indicate why Dr. Chen stated that the U-bolts would strip themselves (Tr. 6743/18-24).

• • The preload used by CPSES is an unknown quantity and this is borne out by NRC Staff witnesses: Johnson, Westerman, and Taylor; see tr. 8813-8817 during the October 1983 hearings.

II - 15 As must be obvious, the failure to include stress levels as high as those shown above and the failure to include thennal effects and other contributors indicates a non-compliance with the provisions of the SRP NUREG 0800, specifi-cally the paragraph on " Design Considerations and Design Loadings." To clarify the NRC SIT's position, consider these statements: At tr. 6742/19-24, Dr. Chen states that pretension effects are written off by engineering judgement. At tr. 6743/21-24 by Dr. Chen: "I think the failures occur in the stripping of the

'U' bolts themselves. The nuts will just be pulled right off, I think." And at tr. 6746/1-3, Dr. Chen states that inspection is for installation, which is prior to heating of the pipe and obviously without seismic activity during opera-tion.

In short, the NRC cannot make even a ballpark guess of what levels of stress and deflection actually are present in the U-bolt / box frame clamp and, consequently, they are equally in the dark in relation to the run pipe.

A feeling for the intensity of the forces and problems associated with pre-loading of 'O' bolts may be found in the Board Notice on page V-23 (which is a report on the meetings between ITT Grinnel and the Staff from Washington):

'The preliminary test results showed the following maximum pipe stresses for a Figure 215 stiff clamp assembly:

aSize 2 frame (11 kips) with 8 inch (schedule 160) pipe

• The 35 ft-lbs preload resulted in a maximum measured pipe stress of 5104 psi.

When the preloaded pipe was statically loaded in compression to 11,000 lbs, the maximum pipe stress measured was 10,562 psi.

• Size 2 frame (11 kips) with 14 inch (schedule 30) pipe hThe 35 ft-lbs preload resulted in a maximum measured pipe stress of 5169 psi.

When the preloaded pipe was statically loaded in compression to 11,520 lbs, the' maximum measured pipe stress was 17,6%7 psi.

II - 16

• Size 3 frame (11 kips) with 24 inch (schedule 20) pipe Whe.40 f t-lbs preload resulted in a maximum measured pipe stress of 36,497 psi. When the preloaded pipe was statically loaded in compression to 11,520 lbs, the maximum measured pipe stress was 53,332 psi. The pipe appeared to exhibit local yielding at about 40,000 psi. It should be noted that while the outer pipe surface measured a maximum stress of 53,331 psi, the inner pipe surface measured a maximum stress of only 5736 psi. The test was not conclusive because of the different locations of the strain gauges on the inner and outer pipe surf ace." (Emphasis added.)

It must be noted that the main steam (32-inch diameter) lines have dozens of these pretorqued 'U' bolts utilized as clamps. The 'U' bolts at CPSES, however, are of low quality steel (A-307) and have loads that are about 100 KIPS for S.S.E. and close to 100 KIPS for 0.B.E. (and this by using non-conservative generic stiffnesses).

An area of vital concern to CASE has been the cumulative effect of the various stiffness factors involved in the design of the support assembly, in-ciuding the clamp assembly, particularly when this assembly is of a novel type.

One must recall that the introduction of the so-called " stiff" clamp evolved due to a requirement to have a stiffer clamp than the stiffness of the snubber or strut assembly. This would then result in an overall stiffness at the node point of the pipe that would be less than the snubber / strut, but not less than the clamp assembly--which would be the result if the clamp were the softer of the assembly components.

This Board Notice refers to the effects on flexibility factors in the following statement at IV-6 of the Notice:

"One important aspect of the pipe clamp is its effect on the stress indices and flexibility factors used for calculating piping stresses.

Although it is common industry practice to locate pipe clamps only on straight pipe, the staff has found cases where specially contoured ipe clamps have been applied on the curved part of a pipe elbow."

p(Emphasis added.)

A II - 17 More importantly in regards to flexibility was the report in the Board Notice of a meeting with 'E' Systems at Salt Lake City, Utah on February 10, 1983.

The report of this meeting (shown in part below) may be found on page V-d and 7 of the Notice:

"E-Systems stated that a unique analysis is performed for each clamp application to include the interaction of the piping with the clamp.

The clamp is modelled with the piping (one diameter length on each side of the clamp) and the combined piping-clamp model is analyzed for four loading conditions: (Emphasis added.)

"1) pipe internal pressure "2) thermal effects

• 3) clamp preload, and

'4) applied dynamic load "The analysis calculates the maximum stresses in the clamp, the required clamp preload, and the maximum clamp loading induced in the piping. E-Systems stated that no purchaser has requested the stress report which includes the clamp-induced pipe load information (except for o.ne utility representative who wanted a copy for his personal file).

"A typical stress report oucput which included a stainless steel 20 inch pipe (schedule 80) modelled with an E-Systems clamp rated to 50 kips was provided to the staff. The analysik indicated that under normal operating conditions (pressure, thermal, and preload) with no applied dynamic load, the clamp can induce a force of 40,614 lbs locally onto the pipe. Under the maximum loading condition (pressure, thermal, preload, and dynamic load) the total clamp-induced local pipe load was 79,376 lbs.

"E-Systems stated that the clamp preload is required to prevent the clamp from lifting off the pipe at rated load. However, E-Systems stated that so.me lift-off or " gapping" will occur at service level C and D conditiore

'We discussed the development of the E-Systems clamp. When asked how their ,

clamp design concept evolved E-Systems stated that they are "in the aircraft business and looks at things differently and in more depth." When General Electric approached E-Systems, GE wanted a specific stiffness requirement for

II - 18 their snubber assembly. E-Systems was concerned with the overall support system stiffness and determined that conventional pipe clamps when coupled with a snubber designed for a large stiffness would result in a total support system stiffness that would be too flexible. Thus, E-Systems determined that a clamp with a stiffness greater than that of the snubber would be required.

In order to achieve the desired stiffness, it was found that preloading the clamp would increase the clamp stiffness. The clamp preload is specified as a torque value and is achieved by applying the calculated torque load to the nuts on the clamp U-bars." ***

The problem with clamp deflection which was addressed by CASE on many occasions during the CPSES operating licensing hearings (as noted on previous pages herein) is referred to in the Board Notice by the inclusion not only of flexibility concerns but also by the companion effects of " lift-off" and

" gapping" (see quotation above). In addition, this problem is also shown in a statement made by the Staff in reference to coments made in a meeting with ITT-Grinnel and which may be found on page V-21 of this Board Notice:

" The staff noted that in the Design Report Summary (DRS) for the Figure 315 clamp, the field torque values were removed and incorporated into the clamp installation instructions instead. Furthermore, there is a note in the DRS that states, " Field torque is required only when there is a stiffness requirement." This note does not appear in the installation instructions.

Thus, the staff expressed two concerns:

il) If a clamp design specification does not stipulate a stiffness require-ment because of a deliberate decision by the purchaser to not use a stiff clamp, then the installation instructions, as written, would still require a torque preload of the clamp. (The installation instructions are the same for clamps with and without a stiffness requirement.)

Grinnell stated that they recently transferred the torque values from the DRS to tne installation instructions and overlooked the transfer of the accompanying note. Grinne'l stated that they will revise their installa-tion instructions accordingly and determine if any plants would be affected by this oversight.

• • • The fact that E-Systems is in the aerospace industry may provoke an adverse reaction from Mr. Reedy and others. However, the Board Notification takes careful note of E-Systems' detailed analysis of the stiff clamp problems aridLsrweJbwukim

II - 19

"(2) With the suggested revision to the installation instructions, the staff expressed a concern that if a clamp design specification does not explicitly stipulate a stiffness requirement because it is assumed by the purchaser that a clamp at rated load will not lift off the pipe, then the clamp would be installed without a preload and might not function as intended during dynamic loadings. Grinnell believes that the design specification of a clamp stiffness value is the responsibility of the purchaser and that if a clamp stiffness is required, then the design specification should provide it." (Emphasis added.) ****

The Staff elects to dismiss major problems with the unique 'U' bolt clamp without any backup, merely by a wave of the hand. See the SIT Report, pages 31 and 32, where the NRC Staff states:

". . . the loads in the principal direction are verified to be within the U-bolt manufacturer's allowable loads during the As-Built Verification Program. Therefore, the Special Inspection Team found the failure to include the deflection of U-bolts in the support deflection analysis to be inconsequential since the deflection of the U-bolt is limited to such small (elastic) move-ment that its contribution to the support deflection analysis is minor. This concern is resolved."

CASE would add at this point that stiffness is of more concern than move-ment, and the cumulative stiffness is the criteria to determine the actual loads--and not the over-optimistic generic stiffness used !y the Applicant, Beyond this, the Staff has no idea of whether the 'U' bolt is in an elastic or a plastic mode, While CASE, the Staff, and the Applicant's positions relative to the effects of clamp flexibility are covered earlier, the persistant views of the Staff are worth noting here. The following footnotes and statements from Dr.

Paul Chen's affadavit relative to the open items on the Walsh/Doyle allegations (received by CASE on October 15,1983) are instructive. From page 21:

"10/ In discussions with Mr. Walsh and Mr. Doyle they asserted that the ASME Code and an unidentified Reg. Guide require piping stress calculations for Class 1 systems to use actual

• • • • The underlined portion of this statement adequately expresses CASE's stated concerns with CPSES 'U' bolts.  ;

l l

)

II - 20 stiffness values of the pipe supports rather than a generic value. Although this is somewhat different from the issue remaining open in the SIT. Report, we have reviewed the Code and Reg. Guide 1.124 ' Service Limits and Loading Combinations for Class Linear-Type Component-Supports' and do not find that they specify the calculational techniques to be used for dyna-mic system analysis. Nor do they require or prohibit the use of either actual calculated stiffness values or generic values.

Both techniques have been accepted'.' (Emphasis added.)

And from page 22 of that affadavit:

"1_1/ In discussion with Messrs. Walsh and Doyle, questions regard-ing the actual stiffness values were raised. They were in-formed that the stiffness values were based on calculations h!.ilizing normal industry techniques. They inquired if de-flections of U-bolts, and flexibility in base plates and con-crete anchorages were included. We indicated that we did not believe that these calculations included computations for the flexibility which Mr. Doyle had asserted must be considered.

U-bolt deflections will be negligible. See SIT Report, p. 29-

33. Concrete anchorage effects will also be negligible for the reasons discussed in connection with Seismic Flexibility. I believe that the calculations provided by Applicants are ade-quate." (Emphasis added.)

The following statement is from page 27 of Dr. Chen's affadavit:

"Thus, the use of generic stiffnesses at CPSES does not adversely affect load capability of the supports or the natural frequency of the affected piping systems. There may be isolated instances of designs such as support CC-1-107-008-E23R in which the supports may be excessively 'sof t' . However, I do not believe that these isolated cases will' result in piping support system which, as a whole, will fail to provide adequate support for the affected piping system."

One must keep in mind that in his affadavit, Dr. Chen states that a re-analysis of the affected nodes (including the node for support CC-107-008-E23R) resulted in the computed load for this support increasing by more than 600 percent. The result of t.his reanalysis required that the plate for the support had to be redesigned. (_This fact is stated on page 26 of the affadavit.)

With this in mind, one must ask the question regarding Dr. Chen's game of nuclear roulette: which isolated supports may have been designed to loads that are only 15 pecent of the load which actually exists?

j

II - 21 The Board Notice expresses its concern about local yielding at VI-2 (.and also at V-23--see earlier in this pleading), although the reason for concern does not represent the overall concerns of CASE (which result from the effects of yielding on unique types and applications existant at CPSES):

" . . . It should be noted that the staff believes these clamp-induced loadings can result in local yielding of the pipe but are not likely to cause gross distortion or rupture of the piping unless the loadings are of extreme magnitude and are coupled with other conditions that could aggravate the situation (e.g., use of thin-walled piping. clamps on or near welds, or clamps on elbows).

The staff's concern is that the general industry practice is to ignore the clamp-induced loadings on the pipe with no criteria that establishes what the limiting conditions are for the pipe nor when clamp-induced stresses should be evaluated."

Some important problems associated with the use of cinched-up 'U'-bolts which were not addressed in the Board Notice, but for which related information exists, includes the stability problem. The Board Notice indicates that yielding does occur as shown above. CASE has addressed this problem and its consequences on many occasions during the CPSES operating licensing hearings.

For example, from CASE Exhibit 763, Doyle Surrebuttal Testimony, page 9, Mr.

Doyle states at lines 12 to 21:

"If frictional forces are relied upon as a means of rotational stability, data must be provided to prove that such friction is adequate under all possible conditions. The effects of cyclic thermal reversals, elasto-plastic deformation, forces induced by self-weight acceleration of the hardware, etc., must all be included.

Without such an analysis, all other arguments are guesswork at best.

In addition, the analysis must also include the stress induced into the pipe due to the ' clamping force' ." (Emphasis added.)

Achieving stability by relying on friction is not rational because of a failure to consider all aspects of the problem, as was pointed out in the Surrebuttal Testimony of Mr. Doyle (CASE Exhibit 763, May 4,1983, page 12, lines 7 to 24):

11 - 22 One " factor involves the use of SA307 bolt material for friction joints.

This material is not allowed for friction joints. See CASE Exhibit 752 (ASME Appendix XVII. Table XVII-2461.1-1. Daae 388; this was attached to TASE's 4/20/83 Brief Regarding Consideration of LOCA in Design Criteria for Pipe Supports), where NOTE 1 states ' Friction tvoe connections loaded in shear are not permitted. The. amount of claging force developed by SA-307 bolts is unpredictable and generally insufficient to prevent com-plete slippage. ' Beyond this, A307 is not reconnended for dynamic appli-cations, as may be noted in Salmon and Johnson ' Steel Structures Design and Behavior,' Chapter 4 Structural Fasteners, at 4.1 Types of Fasteners.

At

"(inthe reference bottom to of A307 page unfinished 85 and continuing)on bolts , thesepage bolts6" (sic are - should rec. nded be 86) for ' loads (which) are piimarily small and static in nature' (by inference not reconnended for dynamic loads). See CASE Exhibit 763F.

" Additionally, the inspection procedures used by the A'pplicants to insure that no cracking of the U-bolt occurs during cinching, while connendable, does not explain how an inspection can be performed when this U-bolt is subjected to thermal expansion of the pipe and the design loads."

(Emphasis added.)

The NRC SIT generally supports the Applicants in reference to the allega-tions of Messrs. Walsh and Doyle, and in the case of unstable supports, the effort relies on undefined " industry practices", as may be noted from this quote (SIT Report, NRC Staff Exhibit 207, page 28):

"It is not general industry practice to explicitly address the overall stability of piping systems together with their supports in design guidelines. Rather, it is standard industry design practice to address only the structural integrity of supports in design guidelines. The Applicant's practice corresponds to this industry practice. Thus, rLo explicit design guidelines address overall stability. Functional ade-i quacy, including stability, of the overall piping system is typically a result of the normal iterative design and review process. Further-ciore, industrial experience has shown in the case of non-rigid pipe supports that if the support element which attaches to the pipe 1_sJrevented from rotating about the axis of the supported pipe atll ti!nes, the

~

pTiilng syiitin and ~its supports 1111~6e a stiilile mechanical system.

Frictional forces are sometimes relied upon to prevent rotation of the support element about the axis of the supported pipe; for example, in the case of pipe clamps or U-bolts." (Emphases added.)

! But a problem with this logic in the SIT report arises when rotational restraint is lost due to yielding of either the pipe or the clamp. Beyond this, the SIT Report dismisses the problem of instability by stating the following (SIT Report i

4

, ,.v- - . - - ,.-------n__.----,-------,.,,.,,.-----.e----- -. ,-,--.- _-,_ -. -- -, - - - - - - - - - - - , - - . -

II - 23 Staff Exhibit 207, pages 27 and 28):

"The question of whether a particular support is stable or unstable when standing alone does not have an important bearing on the functional capability of the piping system. Although individual supports, when considered by themselves may appear to be unstable, it is necessary only that the entire piping system and associated supports be stable when considered as a single mechanical system. Mr. Doyle appears to agree with this concept in his discussion of support No. CC-1-043-026-A33R (Doyle Deposition. Attachment 13X). This drawing shows a vertical sup-port utilizing a U-bclt with zero clearance which is the basis for concern number 2 above. This support was judged to be stable by Mr. Doyle when he stated that:

'even though the structure below is apparently unstable, it takes so little to make it stable that a support horizontally up and downstream is sufficient to keep it stable' (Doyle Deposition,

p. 210)."

But a three-bar link is unstable regardless of what supports exist up or down stream /'"The statement quoted by the NRC SIT (page 27, last line through page 28. first four lines) was taken out of context and referred  ;

to a clamp strut situation and not three bar links. If the SIT had read the entire article, they would have seen that the statements were designed to show that three bar links are unstable under any circumstances, because rotation of the frame surrounding the pipe will occur without lateral displace-ment of the pipe.

This problem of unstable pipe supports, which is generic to Comanche Peak, actually amounts to a missing support, resulting in an inaccurate input for pipe analysis (see NRC Staff Exhibit 201C, paragraph 2). Dr. Chang assumed that improper supports are no problem as long as they will be changed later (Applicants Exhibit 142, page 27, Answer No. 66). Mr. Finneran stated that engineering had not yet detennined whether these supports are unstable or not (Tr. 5268/10-13). Mr. Reedy inferred that the piping system would also have to be considered (Tr. 4973/19-4974/25). And Dr. Chang stated ( Applicants' Exhibit 142, Question and Answer 68, page 28):

• • See CASE Exhibit 669B, Attachment to Doyle Deposition / Testimony, items

, 11YY and 11ZZ.

i 11 - 24 "Q. Is it necessary that each pipe support structure be stable by itself?

"A. (Chang) No, it is not. The important thing is that the piping and supports as a system are stable. Our as-built program will assure that all piping and support systems are stable."

In testimony in May,1983, the NRC Staff made the following statements in defense of unstable supports (Tr. 6697/1-5 by Dr. Chen):

"Although some supports might be unstable, I think the entire piping system together with its supports must be considered.

I think when taken together, if stability is insured (sic), then there is no problem."

Again, Dr. Chen at 6698/12-16 states that if you have one two unstable supports on a run of pipe, you may not have a problem. Beyond this, the SIT on pages 27 and 28 state:

"The Applicant has stated that unstable non-rigid supports have been identified and corrective actions have been or will be taken as necessary before the completion of the design process."

The most shocking statement to come out of the NRC Region IV's Staff was made in reference to why no NCR's were required for unstable supports. See CASE's Findings of Fact, Section III-10, the last paragraph, through Section III-11 which reads as follows:

WITNESS TAYLOR:

. . . Appendix B of (10 CFR), in dealing with nonconforming conditions, does not address nonconforming design. It only addresses the confor-mance of the installed hardware and the inspection thereof to the de-sign. . . III on design control says that you issue field engineering, or field changes, and that they must in turn be reviewed by the ori-ginal designer."

"I don't see that nonconfonnance per se is involved in that."

" JUDGE BLOCH: So it is your opinion that nonconfonnance reports are not required for design deficiencies?"

" WITNESS TAYLOR: That is correct." (Emphasis added.)

In short, it is apparently the NRC Staff's position that if the designer desires to support the main steam lines on egg crates, there would be no de-ficiency, provided that construction uses the size and type of egg crates de-

II - 25 signated by the engineering group!

Another problem area not covered by CASE, but addressed in the Board Notice, involves the resultant effects of " lift-off" as relates to dynamic impact. CASE did address the sister condition which is flexibility effects on loading. The Board Notice reference may be found at V-2 and reads as follows:

. . . The staff also expressed a concern that the E-Systems pipe clamps are designed by E-Systems to the rated load (. service level A and B). However, according to E-Systems, the pipe clamps will lift off the piping at higher loadings (. service level C and D).

Thus, the dynamic impact effect of the clamp on the local pipe sur-face has not been evaluated by Gilbert partly due to the piping designer's unawareness of the E-Systems clamp design assumptions."

The over-all effects of local flexibility can best be found by examining the affadavit of Dr. Chen, on pages 23 through 24, where of 48 calculated loads, 32 increased, 9 of them by more than 25 percent. Of the 6 forces and moments involved at the anchors (of a t0tal of 12 forces and moments), 9 increased.

From the attachment, " Applicants' Additional Pipe Support Generic Stiff-ness Study"2, the actual extent of the problem is obvious. For the anchors, the 9 loads increased by 18 to 46%; and of the 60 loads involved, 41 (67 percent) increased. Rounding off the decimals, 32 of these 41 loads increased from 10 to 200 percent. (Additionally, the " actual stiffness" was determined by the Applicant and CASE does not agree with the stiffness factors used by the Appli-cant.)

The selection of the lines studied was done by Applicant. The main steam was from Unit I and the CC 6-inch line was from Unit 2.

III - 1 SECTION III

' Summary The Board Notice outlined several features of novel clamp designs which could lead to severe stress and flexibility problems. These problems are out-lined below:

(1) Intensify thermal gradient (2) Increase in pipe diameter due to pressure (3) Increase in pipe diameter due to temperature

(_4) Stress resulting from preloading 'U' bolts (5) Flexibility problems with 'U' bolts, particularly those with unknown or inadequate preload (6) Local yielding of pipe wall (7) Dynamic impact effect between clamp and pipe.

Backing up the requirement for consideration of the items listed above, the Board Notice includes the following at page VII-5:

• Subparagraph NB-3624.1 states, 'the design of piping systems shall take_

into account the forces and movements resulting from ... the restraining effects of hanger, supports, and other localized loadings.' Subparagraph NB-3645(a) states, 'the effects of attachments in producing thermal stresses stress concentrations, and restraints on pressure retaining members shall be taken into account in checking for compliance with stress criteria.'

"Thus, the staff concludes that the ASME Code does not require an explicit analysis of the clamp induced stresses, but rather that the design considera-tions take into account the effects of clamp piping interaction. Thus, it is acceptable for a piping designer to implicitly consider the effects of the clamp induced stresses based on a thorough consideration of the analytical design assumptions and the use of appropriate engineering judgement. The

III - 2 design assumptions and bases should be appropriately documented to provide the rationale for making decisions and assuring design adequacy.

dThe Code states in subsubparagraph NB-3672.7(d), 'where assumptions are used in calculations ... the likelihood of underestimates of forces, moments, and stresses, including the effects of stress intensification, shall be evaluated.'-

"Thus, the ASME Code allows the use of imr licit desian considerations orovided the design assumptions do not resQlt in unconservative and unacceptable results.

The staff concludes that it is the responsibility of piping designers to recog-nize the implications of the design assumptions used in the analytical calcula-tions. Furthermore, with resp ict to clamp induced piping stresses, it follows that it is the responsibility of the piping designer to acknowledge the inter-action effects between the piping and the pipe clamp and to be cognizant of those limiting factors where the clamp induced pipe stresses could be signifi-cant and, consequently, to know when the clamp induced pipe stresses should be explicitly evaluated." (Emphasis added.)

The Board Notice further states at VII-6:

" As stated in #5 above, local pipe wall stresses induced by the pipe clamp are not required by the ASME Code to be explicitly evalu~ated. However, if local pipe wall stresses are not explicitly evaluated, then it is the responsibility of the piping designer to evaluate the ' likelihood of underestimates of forces, moments, and stresses' which is an ASME Code requirement. Furthermore, it is the responsibility of the piping designers to be aware of those applications where pipe clamps or other attachments are used on certain piping products that could invalidate the piping stress indices and flexibility factors provided in the ASME Code.

• The staff has determined that under certain conditions clamp-induced loadings on the pipe can be substantial. Furthermore, the staff has found that, in general, the interaction between piping and pip' clamps is not being explicitly evaluated by the piping designers for its effect in the piping integrity. The staff believes that an implicit consideration of the clamp induced pipe stresses is not necessarily a " serious violation" involving safety concerns. However,

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a III - 3 l

the staff believes that potential safety concerns could exist when piping designers are unaware of those limiting conditions where clamp induced pipe stresses can be significant or when the piping designers are not cognizant of certain applications when pipe clamps can be used in an unconservative manner.

"If the situation exists where a plant system does not meet the ASME Code requirements nor provides an equivalent margin of safety, then the plant would not meet NRC requirements. -However, a determination of whether a plant system .

has been designed in accordance with all requirements and qualifies for licensing must be made on a case specific basis and is beyond the scope of

- this document."(Emphasis added.)

It is the obvious intent from the information contained in this Board Notice to convey the position that off-the-wall engineering judgement to justify a

fait accompli is not in compliance with ensuring that the health and safety of 1'

the public is secure.

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The conclusion of the Board Notice (.found at VIII-2) is as follows:

"It is the conclusion of the staff that the utilization of these stiff pipe clamps without an adequate evaluation may result in inducing large stresses in the piping that have not been expli-citly evaluated and, thus, can result in a likelihood of under-estimation of forces, moments, and stresses in the piping system."

(Emphasis added.)

i CASE's Position CASE has consistently maintained its position that major problems occur when novel designs of clamp assemblies are incorporated in the piping systems of nuclear power plants (particularly CPSES) by engineering judgement alone.

The major points of the problem which CASE has put forward as early as mid-August, 1982 are:

(1) Thermal constraint of pipe by built-up box-beams and cinched-up

'U'-bolts i

(2) High levels of stress due to preloading of 'U'-bolts

. - - . . . . , _ , _ . ~ . ~ , . . ~ . _ _ _ _ _ . , . _ . , , _ _ _ . _ . _ . _ - - - _ . . _ _ _ _ . . _ - _ - . - _ _ _ . _ _ . _ - _ _ _ . _ _ .

III - 5 The Staff / Applicant Position Both the St'aff and the Applicant are of the same opinion as relates to the novel pipe / clamp assembly. Both concur that the problems'may be written off by engineering judgement. Both concur that the preload applied to the

'U'-bolts is an unknown quantity.

Beyond this, both argue that the effect of 'O' bolts has a negligible effect on the fundamental frequency of the support system. However, both parties are well aware tha't alteration in any of th'e stiffness factors will have a major impact on the support loads as calculated by Applicant.

(.See previous citations in this pleading.)

Novel Features of the Clamp Assembly at CPSE5 Unknown to the compilers of the Board Notice is a major fact associated with these pipe / clamp assemblies which is advanced by several nuclear facili-ties, including CPSES. The Board Notice addressed the pipe / clamps which are comercially produced, but failed to address those novel designs which are Intthe case of CPSES, the developed by the individual architect-engineer.

unique features incorporated in the design of pipe clamps which was not covered by the Board Notice involves, in part, the following:

(.1) Multiple cinched-up 'U' bolts (2) and (3), (See for example, CASE Exhibit 669B, items 11U0; 13X and 13Y; 13TT.)

(See for example, (2) Plates (flexible) used in lieu of yoke (. rigid).

CASE Exhibit 6698, items 11QQ; 13V; 13FF; etc.)

(3) Wide-flange beam flanges (. flexible) in lieu of yoke (rigid). (See for example, CASE Exhibit 669B, items 1100, 11QQ; 13XX; 13DDD; i

13EEE; 13HHH, etc.)

(_4) Extra-long 'U'-bolt legs (flexibility and thermal differential problems). (See

III - 4 (3) Alteration of the flexibility of the total support system as measured at the node point (4) Yielding locally at the clamp / pipe interface which will result in the ability of the clamp to rotate, which will initiate in-stability in the support.

The Board Notice is in agreement will CASE's position for items 1, 2, and 3 above. As far as item 4, the Staff who wrote this Notice were unaware of this serious defect in the clamp assembly as used at CPSES. But the Board Notice is quite explicit in their acceptance that yielding will occur at the clamp / pipe interface.

See also additional discussions contained in CASE's 11/4/83 Answer to NRC Staff's Affidavits on Open Items Relating to Walsh/Doyle Concerns and Motion for Additional llearings, Affidavit of Jack Doyle, especially at pages 12, line 22, through 13, line ll; and 18, lines 10-18, and Affidavit of Mark Walsh.

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III - 6 for example, CASE Exhibit 669B, items 13XX; 13DDD; 13EEE; 12L; 13S;4Q;4T,etc.)

(5) Masses offset from pipe which rely on friction to eliminate

' rotation (instability) problems. (A-307 should not be used for friction ~ joints; see XVII 2461.4 and see above.) (See,for

, example, CASE Exhibit 6698, items 12L; 12E; 12F; 13JJJ; 13M; 13S;

' etc.)

(6) The 'U' bolts used in most applications at CPSES are commercial items with a built-in clearance. Therefore, when cinched, there is only point contact, not the 1800 found in commercial stiff cl amps.

CASE therefore believes that a thorough evaluation of the variety of novel clamps also be evaluated by the Board prior to licensing CPSES. This evaluation should include but not be limited to establishing the safety fac-i tors, stiffness, and stress levels in the pipe / clamp assembly material at Comanche Peak.

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Respectfully submitted,

$Nh' prs.) Juanita Ellis, President CASE (Citizens Association for Sound Energy) 1426 S. Polk Dallas, Texas 75224 214/946-9446 1

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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of l l

APPLICATION OF TEXAS UTILITIES Q GENERATING COMPANY, ET AL. FOR -

Q Docket Nos. 50-445 '

AN OPERATING LICENSE FOR I and 50-446 COMANCHE PEAK STEAM ELECTRIC Q STATION UNITS #1 AND #2 (CPSES) {

CERTIFICATE OF SERVICE By my signature below, I hereby certify that true and correct copies of CASE's Assessment of Applicability of Board Notification 82-105A to Comanche Peak Steam Electric Station have been sent to the names listed below this 4th day of November ,1983 ,

by: EXptHEXMXXXM1&XXM1)t%8(X/yX)tXWFirst C1 ass Mail.WMW.

Administrative Judge Peter B. Block, Alan S. Rosenthal, Esq. , Chairman U. S. Nuclear Regulatory Commission Atomic Safety and Licensing Appeal Board Atonic Safety and Licensing Board Panel U. S'. Nuclear Regulatory Commission Washington, D. C. 20555 Washington, D. C. 20555 Dr. Kenneth A. McCollom, Dean Dr. W. Reed Johnson, Member -

Division of Engineering, Atomic Safety and Licensing Appeal Board Architecture and Technology U..S. Nuclear Regulatory Commission Oklahoma State University Washington, D. C. 20555 Stillwater, Oklahoma 74074 Thomas S. Moore, Esq., Member Dr. Wal.ter H. Jordan Atomic Safety and Licensing Appeal Board 881 W. Outer Drive U. S. Nuclear Regulatory Commission Oak Ridge, Tennessee 37830 Washington, D. C. 20555 Nicholas S. Reynolds, Esq. Atomic Safety and Licensing Appeal Panel Debevoise & Liberman U. S. Nuclear Regulatory Commission 1200 - 17th St. , N. W. Washington, D. C. 20555 Washington, D. C. 20036 Docketing and Service Section Marjorie Ulman Rothschild, Esq. Office of the Secretary Office of Executive Legal Director U. S. Nuclear Regulatory Commission U. S. Nuclear Regulatory Connission Washington, D. C. 20555 Washington, D. C. 20555 Atomic Safety and Licensing Board Panel U. S. Nuclear Regulatory Commission Washington, D. C. 20555 l

Certificate of Service Page 2 David J. Preister, Esq.

Assistant Attorney General Environmental Protection Division P. O. Box 12548, Capitol. Station Austin, Texas 78711 John Collins Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 611 Ryan Plaza Dr., Suite 1000 Arlington', Texas 76011 Lanny A. Sinkin 114 W. 7th, Suite 220.

Austin, Texas 78701 Dr. David H. Boltz 1422 S. Polk Dallas, Texas '75224 1

Nrs.) Juanita Ellis, President gCASE (Citizens Association for Sound Energ 1426 S. Polk Dallas, Texas 75224 214/946-9446 G

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