ML20107F569
| ML20107F569 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 02/21/1985 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| 2NRC-5-031, 2NRC-5-31, NUDOCS 8502260173 | |
| Download: ML20107F569 (8) | |
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( 12 87 514 2)92 60 Nuclear Construction Division Necon (412) 787-2629 Robinson Plaza, Building 2. Suite 210 Pittsburgh, PA 15205 February 21, 1985 2M United States Nuclear Regulatory Commission Washington, DC 20535 ATTENTION:
Mr. George W. Knighton, Chie f Licensing Branch 3 M
Of fice of Nuclear Reactor Regulation
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SUBJECT:
. Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Responses to Mechanical Engineering Branch Questions Gentlemen:
This leo cer forwards responses to FSAR Mechanical Engineering Branch (MEB) Questions 210.21, 210.34, and 210.39.
p provides a revised response for Question 210.21.
This question was previously closed, however, it is being resubmitted to provide R
more details on the acceptable stress levels for steady state vibrations.
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G Attachment. 2 provides the results for a SSE anchor motion study which has been performed as agreed upon in a meeting with the MEB personnel.
In the October 2, 1984, meeting, two action items were ident ified in order to 1
close Question 210.34. The first act ion was to perform SSE anchor motion 4
study and the second action was to revise Table 3.9B-15 to combine the f aulted condition loads in a single equation with an allowable stress limit j
of 0.95 Sy.
Tabic 3.9B-15 has been accordingly revised and it was submitted l'
with FSAR Amendment 9.
__ provides a revised response for Question 210.39 which
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gives additional informat.*on on the treatment of stresses produced by seismic g
anchor po int motion of p M ag and the thermal expans ion of piping.
As
- sonolementary information, a list of Wastinghouse Class 2 and 3 equipment for M
which they have also supplied supports 'is g#ven in Attachment 4.
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Please inform us of the " closed," "conformatory," or "open" Safety q
Evaluation Report status of these items by February 28, 1985.
If Question
.5 210.39 remains "open" because the MEB considers the position stated in the j
requirement, DLC int ends to request that the proposed j
que s '. ion to be a requirement be submitted to NRC management for approval, in accordance with a
the Of fice of Nuclear Reactor Regulation procedure for management of plant j
Z specific backfitting.
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4, 2260173 B50221 SO ADOCK 05000412 r
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'I Unitsd Stcteo Nuciocr RIgulctory Commission Mr. G3crga W. Knighton, Chief Page 2 Upon your concurrence, the attached responses will be included in a future FSAR Amendment.
DUQUESNE LIGHT COMPANY By
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E.VJ T Woolever Vice President JJS/wjs Attachment cc:
Mr. B. K. Singh, Project Manager (w/a)
Mr. G. Walton, NRC Resident Inspector (w/a)
COMMONWEALTH OF PENNSYLVANIA )
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COUNTY OF ALLEGHENY
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On this d/M day of
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, before me, a Notary Public in and for said Commonwealth and County, personally appeared E. J. Woolever, who being duly sworn, deposed and said-that (1) he is Vice President of Duquesne Light, (2) he is duly authorized to execute and file
-the foregoing. Submittal on behalf of said Company, and (3) the statements set forth in the Submittal are true and correct to the best of his knowledge.
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Notarf Public ANITA ELAINE REITER, NOTARY PUBLIC ROBINSON TOWNSHIP, ALLEGHENY COUNTY MY COMMISSION EXP!RES OCTOBER 20,1986
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5 ATTACHMENT 1
-Question 210.21:
Provide the acceptance criteria that will be used to de termine if the vibration levels observed or measur ed during the preope rat ional testing are acceptable. Specifically address how the vibration asplitudes will be related to a stress level and what stress levels will be used for both steady-state and transient vibration.
Response
Vibration levels are observed or measured during preoperational testing for both steady state and transient vibration cond itions.
The program used to monitor these conditions are described below.
Steady-State Vibrations:
- Visual observations are used for judging acceptability of steady-state vib rat ion.
Visual observations may be aided by hand-held instruments (e.g.,
vibrometers ) when considered ap propriate by engineers expe r i-enced in piping design.
A sc reening /elocity or displacement will be established for use with hand-held instrument results.
If the measurement indicates that the velocity or displacement limit is exceeded, the measured values are reconciled. with the res pective analyses by considering the specific piping configuration, velocity or displacement asplitude measured, stress indices, and the endurance. strength of the material properly.
accounting for high cycle ef fect s.
If system andificat ions are required,. the applicable A SME design Lcalculations are reconciled to
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assure acceptable system charact e ri s tics ~ for all applicable design'
. cond itions.-
The maximum alt ernat ir.,,
stress. intensity (Salt) will be used - to -
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- establish the acceptance stress criteria for steady state vibrations.
For ASf4 Class 1 piping:
alt = C Kh #< 8 S
2 el.
~ 'whe re : c< = 0.615 for materials covered by Figure I-9.1 of ASME III f
oC = 1.0 ' for materials covered by; Figure I-9.2.2 of ASME III.
C '=. Secondary stress index defined in the ASME Code t
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.K2 = Local stress index defined in-the ASME Code '
~~= Maximum zero to peak dynasic mment ' loading. due to M
vibration? displacement 2,
= Section Modulus of. pipe L
'S,t= -. Alternating stress at 106 cycles - from. Figure I-9.1 lof ; ASME. Sectionz III; or ~ alternating stress at' 1011
. 'cyc le s froc ' Figure I-9.2.2 ' of ASME. Sect ion III.. The appropriate curve (A, B, :or C): will be used for Figure I-9.2.2. in accordance with ASME III definitions F
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For ASME Classes 2 and 3 piping, and for ANSI B31.1 piping, the above equation is applicable, setting CK2 2 = 2i where:
i = Stress intensification factor, as defined in the ASMS Code, Subsection NC, ND, or B31.1 Transient Vibrations Transient vibration conditions are subjected to visual and instrumented observations as defined in Table 3.9B-1.
When instrumented observa-tions are take n, the acceptance criteria are based on the applicable fluid system t rans ient analysis (stress, deflection, etc.) results.
Ins trumented observations are considered acceptable if they are within the transient analysis results acceptance criteria.
If ins trume nted results exceed the acceptance criteria, the results are reconciled with the design analysis. When system modifications are required to achieve accep table levels of transient vib rat ion, the ASME design calculations are reviewed and modifiel as neces sary to assure acceptable system characteristics.
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ATTACHMENT 2 Question 210.34 Confirmatory.
This item will become closed upon the completion of the
' following two act ions.
(The second action was incorporated in FSAR Amend-ment 9, December 1984.)
- 1. DLC will deomonstrate that pipe and equipment supports are inherently designed for the effects of SSE anchor motion.
This will be demon-strated by a comparison of typical support strains for the normal / upset and-faulted conditions including the ef fects of 1/2 SSE anchor motion and SSE anchor motion, respectively.
Results:
Though we do not concur with the above being a requirement of our licens-ing basis, the following has been undertaken in response.
-In order to demonstrate pipe and equipment supports inherent capability to withstand ef fects of full SSE anchor motion, 100% of the large bore pipe supports.for = the emergency core cooling system were selected as a sample basis..' Th is system includes a substantial number of la rge bore piping
-supports and is representative of the piping and equipment most critical to plant: safety. All ECCS pipe supports in the safety injection and recir-
. culation spray piping include SSE anchor motion ef fects and are designed agains t 0.95 Sy _ in ' eccordance with FSAR Table 3.9B-15.- The remaining ECCS piping-contains170 large bore supports diich were not originally designed to - include SSE anchor motion.
These have been evaluated to include the ef fect.of SSE, anchor motion. The resulting stresses were compared to 0.95 JSy, and were to be found.to be acceptable in all cases.
'An additional 91 'large bore support s were selected : from various - safety related systems - to establish.the ' capability' of },ipe supports ' to withstand the ' ef fects ' of SSE anchor ' motion on' piping between buildings.
When
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stresses were calculated for-design loads which include SSE anchor motion.
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. and compared to 0.95 Sy, all supports were found to be ' acceptable.
The equipment supports sample included the following equipment from ECCS:
recirculation spray cooler support recirculation _ spray pump; support Additional ~ equipment-supports included were the following:
neutron shield tank cooler support idegasif fer. recovery heat exchanger = support degasifier steam-heater support.
(For _ the equipment = supports above, a comparison was made of support strains i for -the normal / upset and ' faulted conditions incuding '~ the 'ef fects of'1/2
/SSEJanchor motion Jand :SSE anchoro motion, res pect ive ly.
_Results ranged
' f rom a 10-20 percent increase in ' strain;' however, - stress values ' remained well below yield.
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r The above component supports are SWEC supplied supports and they were used in the sample study in order to utilize detailed calculations that were readily available to the architect engineer. However, several Westinghouse supplied component supo rt s, the RHR pump su ppo rt, and the RHR heat exchanger support were reviewed by the architect engineer and the results show a similar pe rcent change in strain and stresses below yield.
The cornponent support s included in this sample study are represent ative of those most critical to plant safety, u
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ATTACHMENT 3 Question 210.39 Does the de sign criteria for compo nent suppo rt s in the BVPS-2 systems categorize the stresses produced by seismic anchor point motion of piping and the thermal expension of piping as primary or secondary?
It is the staf f's pos ition that fo r the des ign of the component suppo rt s, the stresses produced by seismic anchor point no t ion of piping and thermal expansion of piping should be categorized as primary stresses.
Response
The design criteria for the component supports in the BVPS-2 system do not categorize the stresses produced by seismic anchor point action of piping and the thermal expansion of piping as primary or secondary.
Mechanical loads and thermal expansion loads produced by piping are combined and imposed upon the piping suppo rt s.
Combined load ef fects on the supports are maintained within the limits provided as described in the response provided for Question 210.34.
In the initial design phase of auxiliary equipment supplied by Westing-house, the design external nozzle loads imposed on the equipment - are
' t reated as primary loads.
If Westinghouse is requested by the applicant to evaluate calculated piping loads on auxiliary equipment subs eque nt to the' design phase, the - compos ition (i.e.,
de adwe igh t, seismic, thermal, etc.) of the loads is. considered in the evaluation in accordance with the
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requirements of the applicable editicn of the ASME code, Subsection NF, which in certain editions does recognize the self-relieving ' nature of loads' arising from seismic anchor motion and thermal expansion of attached piping.
The treatment of stresses -produced by seismic anchor point motion of-
- piping and thermal expansion of ' piping as primary stresses.is not appli-cable to - BVPS-2 component.' supports because it ~ originated ' with the _1982 winter adenda of the ASME code. ' All. components for BVPS-2 have supports -
designed to code editions covering the years from 1971 through 1981'.
The applicable dates for specific component supports depends on the procure-s ment date as described in the response to Question 210.34 and as detailed in the'ASME code baseline document.
m Since. piping, routed to such equipment has been installed, the conf igura-L tion of piping is finalized: which it. turn - finalizes thermal loadings.
In
.orde r L to lower loadings to meet : the latest ASME code !criterla, additional snubbe rs would have.. to ~ be incorporated into the BVPS-2 piping system design.
Hedever, 'due '.to - the concern of hardware reliability and mainte-
- nance 1 rec,uiremen_ts, the addition of the snubbers would inherently detract
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from the~ safety qualifications of such systems.
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- s; ATTACHMENT 4 Supplementary Information Westinghouse has supplied the following Class 2 and 3 t ank s, heat exchangers, and pumps and their supports:
boric acid batching tank volume control tank pressurizer relief tank accumulator tanks
-letdown heat exchanger regenerative heat exchanger excess letdown heat exchanger RHR heat exch ange r seal water heat exchanger low head safety injection pumps RHR pumps boric acid transfer pumps charging pumps s
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