ML18043A427
| ML18043A427 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 01/11/1979 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | Bixel D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| TASK-03-05.A, TASK-06-02.B, TASK-06-02.D, TASK-06-03, TASK-3-5.A, TASK-RR NUDOCS 7901240032 | |
| Download: ML18043A427 (18) | |
Text
JAN 11 1979 No. 50-255 Mr. David Bixel Nuclear Licensing Administrator Consumers Po1:1er Company 212 West Michigan Avenue Jackson, Michigan 49201
Dear Mr. Bixel:
RE:
PIPE BREAKS INSIDE CONTAINMENT FOR THE P/l.LISADES FACILITY General Design Criterion 4 of Appendix A to Title 10, Code of Federal Regulations 5 P.art 50, requires in part that:
11
- ** structures; systems and components shall be designed to accommodate the effects of 1 oss*of-coolant accidents and shall be appropriately protected against dynamic effects.**
11 Acceptable methods of complying with this regulation
.are, in part, provided in the Standard RevielcJ Plan Section 3.6.2 and Regulatory Guide 1. 1l6 (Protection fa.gainst Pipe \\-.Jhip Inside Containment).
As you are ~ware; the Systematic Evaluation Program-ihcludes a topic on thefffects of Pipe Break on Structures, Systems and Components Inside Containment (III 5.A) v!hich stems from this basic regulation and current licensing criteria.
Our review of material currently in your docket has not revealed sufficient information for technical evaluation of the subject.
As 1>1e have previously stated 3 it would be necessary for the licensees to provide some evaluation for our review of certain SEP topics.
He have determined that your assistance is*needed to supply technical information Hhich wi11 allow us to compare your.plant design to current criteria and to evaluate the significance of potential deviations.
Enclosed is a copy of a letter you received earlier, which summarized current criteria and discusses the SEP review approach presently plann~d.
A meeting will be scheduled ~o discuss this topic with you.
As soon as possible, but at least two weeks prior to that meeting, you should provide any pertinent information you may have, *bi reference to docketed material or copies of additional ~elevant studies or analyses t*,rhich may not have been docketed.
At this rneeting, you should be_
prepared to discuss a progtam for resolving this topic.
Based upon
, the lack of docketed information, \\!Je expect. this program may require I'
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BURNAM Et DAT!!:..
Mr. David Bixel
- 2 JAN 11 1979 If you have any questions prior to the meeting, please call the assignerl P~oject Manager.*
Enclosure:
f\\s stated cc w/enclosure:
See *next page Sincerely, Original Signed. b*y*.,
Denn*
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is L. Z2e2ann Dennis L. Ziemann, Chief Operating Reactors Branch #2 Division of Operating Reactors DISTRIBUTION:
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Consumers Po\\*1er Company cc M. I. Mi 11 er, Es qu i re Isham, Lincoln & Beale Suite 4200 One First National Plaza Chicago, Illinois 60670 Judd L. Bacon, Esquire Consumers Power Company 212
~Jest Michigan Avenue Jackson, Michigan 49201 Paul A. Perry, Secretary Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Myron M. Cherry, Esquire Suite 4501 One IBM Plaza Chicago, Illinois 50611 Kalamazoo Public Library 315 South Rose Street Kalamazoo, Michigan 49006 K M C Inc.
ATTN:
Mr. Jack McEwen 1747 Pennsylvania Avenue, N.W.
Suite 1050 Washington, D. C.
20006 January 11, 1979
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, 0. C. 20555 K M C: Incorporated ATTN:
Mr. Jack McEwen 1747 Pennsylvania Avenue, N.W.
Washington, D. C.
20006 J'uly 20, 1978
SUBJECT:
Assessrrent of Postulated Pipe Breaks Inside Containrrent for SEP Plants {Topic III-5.A)
Dear Mr. McEwen:
As a followup to our discussion on April 28, 1978, we have drafted an outline (enclosed) of three potential approaches which could be used
- for postulating pipe break locations inside the containment for SEP plants (SEP Topic III-5.A). With each approach the following two phases of review are involved:
Phase 1 - Evaluation of the effects of the postulated pipe break on the mechanical integrity of the affected piping run and the operability of its components (i.~., would the* break postula-ted lead to unacceptable degradation of the affected piping system and its components because of reaction loads?).
Phase 2 - Evaluation of the effects of the postulated pipe break on nearby safety-related equipment, structures and systems located inside the containment (i.e., would the break postulated lead to unacceptable degradation of nearby safety-related equiprrent because of pipe whipping or jet impingerrent?).
For operating pressurized water reactors, the pipe break effects (described in Phase 1) are presently being considered on a generic basis (NRR's Technical Acti_vity A-2) as discussed in NRC's letter dated January 25, 1978, to licensees. A.potential exists to expand this generic concern (Technical Activity A-2) to BWRs.
While the scope of this effort is slightly narrower than the SEP effort, we believe that, with only minimal additional effort, it could be expanded to resolve the Phase 1 of the SEP topic described above as well as another SEP topic (VI-2.B Subcompartment Analysis). Therefore, we would propose to integrate much of the output of the generic concern into the SEP, if licensees alsp believe that a significant amount -of effort may be saved.
The assessment of the pipe break effects (described in Phase 2} on safety-related equipment, structures and systems located outside the affec~ system can, in our opinion, proceed independently of the analytical effort required for Phase 1.
Additionally, the consideration of Phase 2 should logically precede Ph.ase-1, since methods to resolve any concern in this area, e.g., additional pipe restraints, may also resolve concerns which could develop in Phase 1.
As we have discussed previous.1y, an effi.cient way to further develop
. our Phase 2 approach in resolving this_topic would be to conduct plant visits with selected licensees and assess the application of the aforementioned approaches on several SE~~~
Enclosure:
As stated cc: Dairyland Power Cooperative Don K. Davis, Chief Systematic Evaluation Program Branch Division of Operating Reactors
.. ~-*
SYSTEM.~TIC EVALUATION PROGRAM ASSESSMENT OF THE EFFECTS OF POSTULATED BREAKS IN FLUID SYSTEM PIPING INSIDE CONTAINMENT
- 1.
INTF
'CTI ON The
- Pose of this paper is to provide guidance for selecting the cesign locations and orientations of postulated breaks in high 1/
energy fluid system pioing-within the reactor containment.
Appro-priate protection for nearby safety~related equipment from the jet impingement and pipe whipping eff~cts resulting from these postulated breaks would then be assessed.
This technical paper is intended to be used in the Systematic Evaluation Program to assess the effects that postulated breaks in high energy piping systems will have on components of essential systems.
The results of this assessment will be combined with other elements of the Systematic Evaluation Program to detennine the staff's overall assessment of the safety adequacy of the operating.
nuclear power plants.
- 2.
DISCUSSION OF POTENTIAL APPROACHES FOR POSTULATING BREAK LOCATIONS Three basic approaches for postulating pipe breaks inside containment are outlined in this paper.
The first one is a fully mechanistic approach which utilizes stress analysis for postulating break locations.
The second one is an effect oriented approach which postulates breaks in the irrurediate vicinity (i.e., most critical locations) of the l! Definitions of underlined phrases are given in Appendix A to this paper.
safety-related equipment.
The third one is a simplified mechanistic approach which postulates breaks at tenninal ends, at each pipe fitting (such as ~lbows, tees, valves and flanges), and at each weld.
Also a-combination of the three approaches *may be utilized if it is justified.
The first approach is an evolution of the current criteria outlined in Regulatory Guide 1.46 and Branch Technical Position (BTP) MEB 3-1.
However, it does not significantly deviate from these criteria. The criteria for this approach are based on the current Mechanical Engineering Branch's (MEB) practice and are extracted from the revised Standard Review Plan(SRP) 3.6.2.
The second approach is an effect oriented approach for postulating break locations which does not require stress analysis.
Its main objective is to provide a basis for protecting safety-related equ~pment located inside containment from a break anywhere in the piping system*.
This approach.is based on the current Auxi 1 i ary Systems Branch's (ASB) practice for postulating break locations in the mainsteam and feedwater lines outside containment as an alternative to separation.
The criteria for this approach are partially extracted from BTP ASB 3-1.
The third approach is a simplified mechanistic approach which does not *
- require "stress analysis. It is also extracted from the revised SRP 3.6.2.
This* appraoch will result in a large number of break locations as a trade-off for not perfonning stress analysis.
- 3.
DESCRIPTION OF THE THREE APPROACHES A.
Mechanistic Approach This approach postulates breaks at terminal ends of each pipe run and at intennediate locations chosen as follows:
2/
- 1)
For seismic Category I, Quality Group A (ASME Code~ Class l) piping when either:
a)
The stress intensity range (including the zero load set) for the limiting nonnal ana upset plant conditions as cal-culated by equation (10) and either equation (12) or (13) of NB-3653 of the ASME Code exceeds 2. 4 Sm; or b) The cumulative usage factor derived from the piping fatigue analysis under the loading resulting from the normal, upset and testing plant conditions exceeds 0.1.
- 2)
For seismic Category I, Quality Group B (ASME Code Class 2)° piping when the stress for.the limiting nonnal and upset conditions as calculated by the sum of equations (9) and (10) of NC-3652 of the ASME Code exceeds 0.8(1.2 Sh+ SA).
- 3)
For seismic Category I, Quality Group C (ASME Code Class 3) piping when the stress for the limiting nonnal and upset conditions as calculated by the sum ~f equations (9) and (10) of ND-3652 of the ASME Code exceeds 0.8(1.2 Sh+ SA).
'!:..!Section III of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, 11Nuclear Power Plant Components".
_ 4)
For seismic Category I, Quality Group D piping when the stress for the limiting normal and upset conditions as calculated by the sum of equations (12) and (13) of 104.8 of ANSI 831.1 ll exceeds 0.8(1.2 Sh+ SA).
S)
For non-seismic Category I piping everywhere along the run.
B.
Effect Orientated Approach Pipe breaks in each run of a high energy piping system should be postulated at the following locations:
- 1)
At the terminal ends of the run; and
- 2)
At effect oriented intermediate locations chosen in accordance with the fo1lowing:
a)
A longitudinal pipe break at the point which produces the greatest jet impingement loading on each component of each essential system (typically this would be the point of closest approach); and b)
A circumferential pipe break at the point which produces the greatest pipe whip loading on each c~mponent of each essential system.
1l American National Standard Code for Pressure Piping ANSI 831.1, "Power Piping".
C.
Simolified Mechanistic Aooroach This approach postulates breaks at tenninal ends, at each pipe fitting (such as elbows, tees, valves and flanges), and at each weld.
- 4.
TYPES OF BREAKS The following types of pipe breaks should be postulated to occur at the locations determined in Section 3 above:
A.
A circumferential break in runs of piping greater than 1 inch nominal size at:
- 1)
Each terminal end; and at
- 2)
Each of the following intennediate locations:
a)
Chosen in accordance with ~he effect oriented criteria to produc~ the greatest pipe whip loading on each component of each essential system [3.B.2)b)].
b)
Chosen in accordance with the simplified mechanistic approach (3.C.).
c)
Chosen in accordance with the mechanistic approach (3.A.).
With the exception of locations chosen based on high usage factor [3.A.l)b)] or on being a non-seismic Category I piping system [3.A.5)], circumferential breaks need not be postulated when the circumferential stress is equal to or greater than 1.5 times the longitudinal stress.
B.
A longitudinal break in runs of piping 4 inch and greater nominal size at each of the following intermediate locations:
- 1)
Chosen in accordance with the effect oriented criteria to produce the greatest jet impingement loading on each comoonent of each essential system [3.B.2)a)].
- 2)
Chosen in accordance with the simplified mechanistic approach
( 3. c.).
- 3)
Chosen in accordance with the mechanistic approach (3.A.). With the exception of locations chosen based on high usage factor
[3..A.l)b)] or on being a non-seismic Category I piping system
[3.A.5)], longitudinal breaks!eed not be postulated when the longitudinal stress is equal to or greater than 1.5 times the circumferential stress.
- 5.
EFFECTS OF BREAKS The effects of the above postulated breaks should be calculated based on the following:
A.
Circumferential Breaks
- 1)
Should be assumed to result in pipe severance and separation amounting to at least a one diameter lateral displacement
... of the ruptured piping sections unless physically limited by piping restraints, structural members, or piping stiff-ness a~ may be demonstrated by inelastic limit analysis.
- 2)
The dynamic force of the jet discharge at the break location should be based on the effective cross sec.tiona 1 f1 ow area of the pipe.
- 3)
Pipe whipping should be assumed to occur in the plane* defined by the piping geometry and configuration, and to cause move-ment of the pipe in the direction of the jet reaction.
B.
Lanai tu di na 1 Breaks
- 1)
Should be assurred to result in an axial split without pipe severance.
a)
For break locations selected in accordance with either the me.chan1stic (3.A.) or simplified mechanistic (3.C.)
approaches, splits should be oriented (but not concurrently) at two diametrically opposea points on_ the piping circumference such that the jet reaction causes out-of-plane bending of the piping configuration. Alternatively, a single split may be assumed at the section of highest tensile stress as detennined by detailed stress analysis.
... b)
For break locations selected in accordance with the effect oriented approach [3.Br2)a)], a single split should be oriented such that it pr~duces the greatest jet impingement loading on the component of the essential system.
- 2)
The dynamic force of the fluid jet discharge should be based on a circular or elliptical (20 by 1/20) break area equal to the cross sectional flow area of the pipe at the break location. Alternatively, a smaller split may be assumed where it can be justified using conservative assumptions and methods based on fracture mechanics.
- 3)
Piping movement should be assumed to occur in the direction of the jet reaction unless physically limited by structural members, piping restraints, or piping stiffness as demonstrated by inelastic analysis.
C.
Breaks should be assumed to fully develop instantaneously.
Alternatively, a detai.led analysis may be perfonned to establish a finite opening time.
D.
Jet discharges should be assurred to fully develop instantaneously and to sweep the entire arc between the pipe 1s initial
0
- and final positions.
Alternatively, a detailed analysis may.be perfonned to establish the actual area of jet discharge sweep.
E.
The dynamic force of the jet discharge at the break location should be based on a calculated fluid pressure as modified by an analytically or experimentally detennined.
thrust coefficient.
Limited pipe displacement at the break location, line restriction, flow limiters, positive pump controlled flow, and the absence of energy reservoirs may be taken into account, as applicable, in the reduction of the jet discharge.
- f.
The environmental effects of changes in pressure, temperature, and humidity shouid be included.
G.
Flooding, if applicable, shoult! be considered in the affected compartment and any communicating compartments.
Flooding effects should be determined on the basis of a conservatively estimated time period for corrective action.
H.
All unprotected components within the affected compartment shoul.d be assumed to be wetted by humidity and indirect spray.
APPENDIX A DEFINITIONS Components of ~ssential Systems.
Components of systems required to shut down t11e reactor and mitigate the consequences of a postulated piping failure, without offsite power.
The specific systems for which protection is necessary will be delineated at a later date.
- High-Energy Fluid Systems.
Fluid systems that, during nonnal plant conditions, are either in operation or maintained pressurized under conditions where either or both of the following are met:
- a.
maximum operating temperature exceeds 200°F, or
- b.
maximum operating pressure exceeds 275 psig.
Normal Plant Conditions.
Plant operating conditions during reactor startup, operation at power, hot standby, or reactor cooldown to cold shutdown condition.
SA.
Allowable stress. range for thermai' expansion as defined in NC-3652 and ND-3652 of the ASME Code and 104.8 of ANSI 831. l.
Sh.
Allowable stresses at maximum (hot) temperature as defined in NC-3652 and ND-3652 of the ASME Code and 104.8 of ANSI B31.l.
S. Design stress intensity as defin~d in Article NB-3600 of the ASME m
c"ode.
Terminal Ends.
Extremities of piping runs that connect to large components (such as vessels, pumps) or pipe anchors that act as constraints to piping
- ~r'
- movement including rotational movement from static or dynamic loading.
A branch connection to a main piping run is a terminal end of the branch run.
Inter.s..ections of runs of comparable size and fixity need not be considered terminal ends when the piping model includes both the run and branch piping and the intersection is not rigidly constrained to the building structure.
Test Pl ant Conditions. Those pl ant conditions associated with the production, preservice, and inservice testing of components and systems.
Uoset Plant Conditions.
Plant operating conditions during system transients that may occur with moderate frequency during plant service life and are anticipated operational occurrences, but not during system testing.
The Operating Basis Earthquake (OBE) is considered to be an upset plant condition.