ML17174A126
| ML17174A126 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 11/06/1979 |
| From: | Janecek R COMMONWEALTH EDISON CO. |
| To: | Oconnor P Office of Nuclear Reactor Regulation |
| References | |
| TASK-03-06, TASK-3-6, TASK-RR 5667, 5667-00, NUDOCS 7911130284 | |
| Download: ML17174A126 (11) | |
Text
- -
.. e Commonwealth.on
- One First National Pl
_!licago, Illinois Address Reply to: Pos Office Box 767 Chicago. Illinois 60690
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November 6, 1979 Mr. Paul W *. O'Connor Operating Reactors - Branch 2 U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Dresden Station Units 1 and 2 Systematic Evaluation Program Seismic Review Meeting Minutes Dea£ Mr. O'Connor:
Enclosed for your information and use is one copy of meeting minutes prepared by Sargent & Lundy following our October 11, 1979 meeting with the NRC Staff and the Senior Seismic Review Team.
Please address any questions you may have concerning this matter to this office.
Very truly yours,
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Robert F. Janecek Nuclear Licensing Administrator Boiling Water Reactors RFJ:mae enclosure
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SARGENT 8c LUNDY ENGINEERS CHICAGO Project No. 5667-00 Commonwealth Edison Company Dresden Station -
Units 1 & 2 Notes of Meeting Bethesda, Maryland October 11, 1979 Nuclear Regulatory Commission Off ices Systematic Evaluation Program THOSE PRESENT:
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F. Janecek
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Commonwealth Edison Company B. Palagi
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P. Smith
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Koppe Nuclear Services Corporation E. Schaff stell KMC, Inc.
Cheng
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Nuclear Regulatory Commission Crutchfield
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H. Hofmayer
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Levine
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- w. O'Connor
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J. H~ll NRC Consultants D. Stevenson Loziuk
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Sargent & Lundy J. Victorine
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Walser
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Purpose The purpose of this meeting was to discuss the conclusion of the year-long seismic re-review of Dresden 2 as con-duc*ted by the NRC staff and its consultants, to decide on a program for Commonwealth Edison Company to address the remaining NRC c~ncerns and to take appropriate action as required.
- 2.
Reactor Pressure Vessel The NRC consultants were concerned that the analysis furnished by General Electric Company for the reactor pressure vessel skirt was not adequate.
October 24, 1979
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.Dresden Station - Units 1 & 2 Notes of Meeting October 11, 1979 October 24, 1979 Page 2 In particular, the compression affects and frequency affects were omitted from the original analysis.
- Also, the recirculation system pipe loads on the reactor vessel nozzles do not match the loads which are stated in the seismic analysis for the reactor recirculation system piping.
The NRC requested that a new analysis be performed for the reactor pressure vessel in accordance with current state-of-the-art techniques.
The NRC and its consultants are not concerned that the reactor vessel will be over stressed, but it is their judgment thatthe analysis performed was not rigorous to the degree that it would support the conclusion.
The NRC consultants stated that they would be satisfied if a modern seismic analysis for a current vintage boiling water reactor was submitted in the way of satisfying the analytical requirements for Dresden Unit 2 along with an argument for the similitude between vessels.
- 3.
Reactor Pressure Vessel Internals The NRC consultants* advised that CECo submitted insufficient information regarding the internals of the reactor pressure vessel.
The core support structure is the main NRC concern.
A list of missing GE diawings for reactor pressure vessel internals was handed to CECo with the agreement that CECo would obtain these drawings and forward them to the NRC.
However,.the NRC cautioned that merely providing these drawings would not alleviate their concern.
The new seismic analysis as requested in Item 2 of these notes should also address the reactor pre$sure vessel
- inte:tna~s.
- 4.
Control Rod Drive Tubing The NRC consultants advised that, in. their opinion, the control rod drive module support rack is too flexible when compared to the rigid mounting of the tubing system, and they are concerned that.there may be large *displace-ments causing th.e CRD tubing to rupture at the inter-face of the rack with ~he overhead piping ~ystem. The NRC consultants also questioned the flexibility of the tubing supports between the rack and the reactor.
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- ENGINEERS CHICAGO Conunonwealth Edison Company Dresden Station -
Units 1 &. 2 October 24, 1979 Page 3 Notes of Meeting Octgber 11, 1979
- 5.
The NRC requested that a new analysis be provided for the piping system between the modules and the overhead tubing runs.
A walkdown of these lines would be required to determine support spacing and support configuration pr1or to an analysis.
The NRC also expressed its concern about the adequacy of the foundation anchor bolts and asked CECo to provide the installation drawin.gs and/or procedures
- which were used to design the foundation for the CRD racks and to install the racks.*
CECo ag*reed to provide foundation drawings and pro-cedures.
Motor Operated Valves arid 4" and Smaller Piping* systems The NRC consultants advised that they were satisfied with the argument provided by CECo and S&L in February of 1979 concerning eccentric masses for motor operated valves in 4" diameter and larger piping systems.
- However, they were concerned that a similar argument had not been made for motor operated and air operated valves in smaller piping systems which had their seismic support designed in accordance with the Blume's curves.
As none of the meeting attendees knew how extensively motor operated and air operated valves were used in small piping systems, CECo agreed to prepare a tabulation to identify all nuclear safety related valves 2" in diameter and smaller, as well as all nuclear safety related valves in.pipelines 4" diameter and smaller, which were designed in accordance with the Blume's seismic curves and which have larg~ center of gravities.
S&L explained that they had prepared calculations which showed that the torsional or bending stresses increased the local piping stress between 600 and 1,900 psi.
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Commonwealth Edison Company October 24, 1979 Page 4 Dresden Station - Units 1 & 2 Notes of Meeting October 11, 1979
- 6.
- 7.
A question was raised why the NRC was concerned in their SEP review about 2" and smaller piping and valve~ whereas in the IE Bulletin 79-14, the r~quirement to inspect 2" and smaller pipelines was waived by the NRC.
The NRC reviewers were at a loss to explain this disparity and agreed to provide CECo with an answer at some time in the future.
The NRC requested that CECo develop a rigo.ro\\ls.analysis (as a result of the eccentricity of the mot9r or air operated valves) to show the increase in stress was acceptable.
CECo would do so after the valve list was compiled and the walkdown required by IE Bulletin 79-14 was completed for 2~" and larger lines.
Pipe Support Spacing The NRC concluded that the Blwne's seismic curve method of analysis was an adequate method of designing seismic pipe supports; however, they suspect that the field application of the Blwne's curves was not rigorous.
Therefore, the NRC requested that CECo provide the NRC with some veri~ication that the Blume's curves had been
- strictly ~pplied s6 as to keep the spans in the rigid range as suggested by Blume's method.. The NRC did not state tre extent of verification that would be satisfactory; however, the answer to the IE 79-14 Bulletin may be sufficient.
CECO would look at some sample support spacings once the information was available from the IE Bulletin 79-14 walkdown.
Reactor Recirculation Pump Su~ports The NRC consu~tants questioned that the Bl~e's analysis of the reactoi:- recirculation piping system stat,es t.hat the pump is r~gidly mounted.
The actµal installation of the pump af>pears to be as a flexible element in the system.
It was mentioned that the actual support of the pump is by means of not only the piping* system but by rigid sway rods and constant support type hangers.
CECo agreed to provide drawings ofi the support system for the reactor recirculation pumps.
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Units 1 & 2
- -October 24, 1979 Page 5 Notes of Meeting Octobe~ 11, 1979
- 8.
The NRC cautioned that even after these drawings had been provided, it was still their opinion that a new seismic analysis should be made on th~ reactor
. recirculation piping system.
CECo agreed to review
.the assumption in the Blume calculations.
Battery Racks The NRC consultants advised that they had performed their own independent analysis of the Dresden Unit 2 battery racks *and concluded that these racks responded with a frequency.of about 20 Hz and could therefore be considered as rigid structures.
However, they were concerned that the wooden cell braces could fail in bending as a result of the battery cells sliding during a seismic event.
The NRC stated that if a co~fficient of friction greater than 0.20 existed between the glass battery cells and the rack that the rails would not be loaded and, thus, not fail.
The NRC suggested.two courses of action:
A.
Make an evaluation of the coefficient of friction between the battery cells and battery rack.
If the coefficient of friction was in excess of 0.20, no modifications needed to be made.
B.
The wooden cell braces be either replaced or reinforced with structural steel members.
- with regard to option B, the NRC stated that whatever modifications were made to the battery rack, they should be engineered rather than simply adding steel to the rack for appearance sake.
The NRCmentioned that the Oyster Creek Plant staff had already modified their battery rack and that a similar design would appear to be acceptable.
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Commonwealth Edison Company Dresden Station - Units l& 2 Notes of Meeting October 11, 1979
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October 24, 1979 Page 6 9~
S~fety Related Electrical.Equipment (Motor Control Centers, Switchgear, Control Panels_, Instrument Racks, Transformers, Inverters, *Etc.*}
The NRC stated that although CECo had provided a seismic test report for a Cutler-Hammer motor control center used for the new Dresden 1 HPCI System project, CECo had not verified similarity between the new motor control center and the existing motor control centers.
The NRC advised.that in order to. satisfy their concer11,.
- they would like CECo to conduct an insitu test of
.representative electrica-.l equipment using dynamic testing and monitoring equipment to show that the response frequency of the equipment is out of the range of. the 1 building seismic response frequency.
The NRC also expressed its concern that eiectrical equipment items may not have been anchored securely to the floor and requested that CECo:
A} prepare a program to identify all safety related electrical equipment, B} make a.reconnaissance of the station to verify that all electrical equipment was secureiy bolted to the floor or welded to embedments in the.floor, and C} evaluate each individual attachment detail to verify that it complied with the original design drawings or standards.
- 10.
Electrical Equipment Cabinet Resonance The NRC consultants mentioned that GE had issued an N-ID report in 1971 detailing a proposed modificatio.n. to *the main control panels to eliminate F seismically-induced resonance problem.
The proposed modification involved adding additional structural steel elements ~ithin the panel.
I CECo agreed to r~search their files and conduct.a field inspection to confirm as soon as possible that the proposed panel modification had been implemented.
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SARGENT 8c LUNDY ENGINEERS CHICAGO Conunonwealth Edison Company Dresden Station - Units 1 & 2 October 24, 1979 Page 7 Notes of Meeting October 11, 1979
- 11.
Electrical Cable Trays and Supports
- 12.
.The NRC consultants advised that they had concluded since there were no lateral supports on the cable trays, the tray system may not be completely seismically adequate.
They mentioned that they were aware of test results*
that indicated the horizontal motion produced during an earthquake resulted in an angle of as much as 30° with the vertical..
Their concern was that low cycle fatigue of the threaded rods would degrade the seismic adequacy of the overall tray system if the rods were to fail.
CECo advised that they were attempting to obtain copies of the Bechtel generic seismic cable tray test which they understood concluded that cable tray systems simi-lar to Dresden Unit 2 could withstand the design basis earthquake without lateral supports.
The NRC agreed that they would like to see the results of this test.
- cECo said* they would provide the NRC with the test report if and when it becomes available.
The **NRC also mentioned that it was aware that certain tests conducted by Sandia Laboratories for fire protection demonstrated.that there may be some reduction in the seismic damping of cable trays when the cables were totally submerged in fireproofing materials.
In other words, plain cables in the. cable trays provided a more seismically damped system than cables coated with fireproofing material.
Torus Sway Rods The NRC acknowledged that they were aware of the Mark I Containment Long-Term Program currently evaluating torus sway rods, among other concerns.
However, they stated tha*t they would like an early separate evaluation of the structural adequacy of the sway rods due to fatigue failure.
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Untts 1 & 2 October 24, 1979 Page 8 Notes of Meeting October 11, 1979
- 13.
Interaction Effects The NRC requested that CECo conduct an interaction review to confirm that safety related equipment could not be
~egraded during a seismic everit as a result of a piece
.of non-safety related equipment overhead falling or adjacent non~safety related items sliding into the
.safety grade equipment.
The NRC stated that they were not interested in having CECo conduct a formal seismic analysis of each non-safety equipment item.
- However, they would be satisfied that *after *a recon-naissance of.the -station is made,.all anchor bolts :are inspected for tightness in overhead equipment arid that some housekeeping program be developed so that loose
- i terns such as barrels, forklift trucks, etc., are not placed in a position that an earthquake would cause them to impact with safety related equipment items.
- 14.
Reactor Building/Turbine Building Common *Wall
'.The NRC stated 'that they had discussed the original seismic calculations with Blume & Associates recently, and Blume provided additional supporting calculations which increased the stiffness of the turbine building.
The NRC's concern for the safety factor of the common
- wall between the ~eacto~ and turbine buildings.~s stil1 under investigation.
- 15.
Action.Program The NRC requested that CECo develop a program for responding to the remaining NRC concerns and that CECO arrange a telephone conference call on -October 26, 1979, with the NRC to apprise them of how the program is developing..
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A SARGENT Bi: LUNDY ENGINEERS Commonwealth Edison Company Dresden Station -
Units 1 & 2 Notes of Meeting October 11, 1979 CHICAGO October 24, 1979 Page 9*
- 16. *nresden Unit 1 -
Systematic Evaluation Review The NRC handed CEco*a proposed schedule for the Dresden 1 Systematic Evaluation Program which proposed dates for submittal of various information items in order to support the NRC's overall review of Dresden Unit 1.
It was stated by CECo during the meeting that the earliest starting date that CECo could agree to is January 1, 1980.
A copy of the handout is attached to these meeting notes as Exhibit;.[J:;z/~~
(/,/{Ji. Victorine TJV:pp Attachment Copies:
LEA (1)
WAC (1)
RNB (1)
WGH (4)
.DCM (5)
JMM (4)
RJM (1)
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II.
DRESDEN 1 (General Group 2 Seis c Milestones)
A.
Seismic input available B.
Analysis and evaluation of reactor btiilding and RCPB complete {Report)*
C.
Analysis of other Cat. 1 buildings complete (floor spectra, response profiles)
D.
Analysis and evaluation of safe shutdown systems complete (piping, anchorage of mechanical/electrical equipment) (Report)
E.
Structura~ Evaluatibns of {C) above complete (Report)
F.
Analysis and evaluation of ECCS/ES systems complete (piping, anchorage of mechanical/
electrical equipment)
G.
Evaluation of mechanical/electrical equipment complete H.
Licensee submjts final reports (with action plan)
I.
NRC review complete J.
Interim *NRC Seismic Report/start of integrated
- assessment WEEK 20 24 40 40 48 64 72 80 88 I I ! !
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