ML18038B713
| ML18038B713 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/20/1996 |
| From: | Chen P NRC (Affiliation Not Assigned) |
| To: | Wessman R NRC (Affiliation Not Assigned) |
| References | |
| REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR NUDOCS 9606250081 | |
| Download: ML18038B713 (26) | |
Text
<PR A500 P
+
O Cy, oO A0
/p
~O
++*+,+
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2055&0001 June 20, 1996 THRU:
HEHORANDUH TO:
Richard H. Messman, Chief Hechanical Engineering Branch Division of'ngineering Kamal A. Hanoly, Chief Component Integrity Section Hechanical Engineering Branch FROH:
SUBJECT:
Pei-Ying Chen, Sr. Hechanical Engineer Component Integrity Section Hechanical Engineering Branch TRIP REPORT AUDIT OF BROGANS FERRY UNIT 3 USI A-46/IPEEE IN-PROGRESS SEISHIC MALKDOMN,. OCTOBER 16-20, 1995 During the week of October 16-20,
- 1995, a team. of two NRR staff members from EHEB and
- ECGB, and two contractors from Brookhaven National 'Laboratory, conducted an audit of the USI A-46/IPEEE in-progress seismic walkdown activities performed by the licensee. of the Browns Ferry Unit 3 plant.
The RES staff did not participate in this audit due to other coIINI'itments.
The licensee is implementing the Generic Implementation Procedure, Revision 2
(GIP-2), developed by the Seismic qualification Utility Group (SHRUG) and previously approved by the NRC.
The objective of the audit was to observe and assess the licensee's effectiveness in identifying the seismic concerns with the safe shutdown electrical and mechanical equipment..
The audit did not focus on the evaluation of seismic adequacy of equipment, which will be done when the licensee submits its A-46 evaluation reports to.the NRC.
Therefore, the audit did not cover the full extent of the necessary staff's effort to reach closure on these two programs.
An entrance meeting in the early afternoon of October 16," 1995, and an exit meeting the morning of October 20,
- 1995, were held at the site.
The attendees of these two meetings are listed in Attachment l.
Attachment 2 provides the details of the staff audit results, observations and assessments, of the l.fcensee's seismic walkdown activities.
The audit team has successfully, accomplished its objectives of assessing the licensee's effectiveness in its seismic walkdown activities and gathering information.
concerning the licensee's practice in implementing the GIP-2.
The audit team found that the licensee's walkdowns of seismic adequacy of mechanical and electrical equipment were performed by its contractor, E(E, Inc., 'and the walkdowns of,cable and conduit raceways were conducted by the licensee's engineers.
All walkdown engineers that the audit team contacted had the SgUG-sponsored training course and were qualified for the seismic walkdowns.
CONTACT:
P.
Y. Chen, NRR 415-2789 960625008i
'&0620
'PDR ADOCK 05000296 P
4l 0
~r Ill
Richard Wessman However, the audit team noticed some potential concerns in the areas of interface between different disciplines, some of the personal judgements exercised by the licensee's engineers or its contractor, and the use of industry guidelines that were not reviewed and approved by the staff.
During the audit, the staff identified a technical concern with the use of GIP-2 criteria by the licensee regarding the alternative methods for the comparison of seismic demand with the seismic capacity for equipment installed in the plant.
The technical details of the.concern are described in Attachment 2 under the heading of "Response Spectra."
The staff conveyed the concern to TVA at the Browns Ferry audit exit meeting, and informed the S(UG Steering Group of the potential generic impact through the representative of the MPR Associates at the meeting.
The issue is being discussed between the staff and the SHRUG Steering Group.-
'Attachments:
l.
Attendance Lists 2.
Audit Report Central Files NRC PDR EMEB RF/CHRON AThadani Bsheron Glainas Gbagchi Rrothman RPZimmerman SAVarga JFStolz Ddorman
- see previous concurrences JWilliams DOCUMENT NAME: G:iCHENiBRSTRIP..696 To receive a copy of this docuaent, indicate in the box,C=Copy u/o attachment/enclosure E"-Copy ufth attachment/enciosure N ~ No c NAME DATE PYChen 6/06/96 OFFICE EMEB:DE*
E ECGB:DE*
EMEB:DE'manol
~//96 YKim 6/07/96
- OFFICIAL'ECORD COPY
Il
ST N-G S
S o
0 t e
6 9
James M. Davenport Kamal K. Bandyopadhyay Yong S.
Kim Pei-Ying Chen Daniel D. Kana R.
D. Cutsinger Joe Valente Steven W. Austin John 0. Dizon J.
R.
G1ass ct ME Joe Lenahan Joe Milliams Len Mert Richard Starck Paul Baughman Perry Robinson, Pedro Salas H L. Milliams James M. Davenport Yong S.
Kim Pei-Ying Chen R.
D. Cutsinger Joe 'Valente John 0. Dizon R. Glass 99 TVA, Licensing BNL/NRC Team NRC/NRR/OE NRC/NRR/OE SMRI/NRC TVAN, Corp. Civil TVA/BFN Site Eng.
TVA/BFN Site Lic.
EQE TVA/BFN Site Eng.
NRC, RII NRC/NRR Project Hanager NRC, Sr. Resident HPR Associates, Inc.
.EQE Qinston 8 Strawn TVA
EQE TVA/BFN Site Eng.
ATTACHMENT 1
BROWNS FERRY IN-PROGRESS SEISHIC WALKDOWN AUDIT REPORT INTRODUCTION The licensee for Browns Ferry Unit 3 is implementing the USI A-46 program following the procedures developed by the Seismic Qualification Utilities Group (SQUG) and documented in the Generic Implementation Procedure, Rev; 2
(GIP-2, Reference 1).
An audit of the licensee's "in-progress walkdown" for the A-46 implementation program has been performed at the site on October 16-20, 1995.
BNL members participated on October 16-18, 1995.
The purpose of the audit was to observe the licensee's implementation plan, and assess whether the licensee is reasonably implementing the criteria and procedures delineated in the GIP-2 and the NRC Supplemental Safety Evaluation Report (Reference 2).
In addition, the audi.t offered the staff an opportunity to review the qualification of the licensee's seismic review team members.
SEISHIC REVIEW TEAII The Seismic Review Team (SRT) for Browns Ferry consisted of the fo11owing civil engineers from EQE International:
John 0. Dizon Richard 'D. Augustine
,Brantley C. Buerger Farzin R. Beigi James R. Disser All of the five engineers have attended the SQUG training course on equipment walkdown screening and seismic evaluation.
The. SRT members have substantial experience in practicing structural engineering, especially dynamics.
Three of the SRT members have a.professional engineering license.
Thus, these engineers are well qualified for the A-46 work and exceed the minimum qualification requirements for seismic engineers as delineated in the GIP-2.
Although some interaction might have taken place, it was not. clear whether a
system engineer or a plant operator participated in the seismic walkdown effort as recoaeended by the GIP-2..
Such synergisms are expected to provide a
reliable comprehensive review and a better understanding of the safety
,functions of the equipment.
Horeover, the audit team learned that the EQE engineers perform the walkdown in a group of two engineers.
The group always includes at least one professional engineer as required by the GIP-2.
The other personnel involved in the program included cable tray. and conduit engineers Anand Relwani and Cesar
- Pascna, who were trained by SQUG, system engineers John D. HcCamy and Hatthew Williams, and a field coordinator consultant, Roy Smallwood.
SAFE 'SHUTDOWN EQUIPHENT According to the licensee, the safe shutdown equipment list (SSEL) was prepared considering the need.for maintaining the safe shutdown condition for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Approximately 400 equipment items are in the SSEL for Unit 3 (and 650 for Unit 2}.
Attachment 2
II 4
RESPONSE
SPECTRA The Browns Ferry site SSE ground'otion spectrum (approximately 0.3g spectral acceleration for a critical damping value of 5X and 0.2g ZPA) is substantially below the GIP.-2 "Bounding Spectrum" (0.8g spectral acceleration for critical damping value of 5X and 0.33g ZPA).
Therefore, in.accordance with GIP-2, equipment items located at an elevation of up to 40-feet above effective grade may be adequate, provided that they satisfy the fundamental frequency requirement of about 8 Hz or higher.
Alternatively, the GIP-2 also. allows a
comparison of the in-structure response spectrum with the equipment capacity spectrum, i.e.,
"Reference Spectrum."
During the staff's audit, it was noted that if. this second alternative is used, the licensing-basis seismic demands for some equipment items installed. in the Diesel. Generator (DG) Building and the Intake Pumping Station (IPS) will substantially exceed the "Reference Spectrum," i.e., the seismic demand measured by the in-structure response
'pectrum exceeds the seismic capacity of some equipment at certain elevations.
Attachment 3 (Fig B.,l. I), provided by the licensee during the audit, depicts curves representing seismic capacity vs. seismic demand for DG and IPS bui,ldings.
The figure signifies the magnitude of exceedence above the Referehce Spectrum t(1.5 x Bounding Spectrum) at different frequencies for various floor elevations in, these buildings.
The staff does not consider the licensee's choice of the first alternative in the GIP-2 acceptable, since it results in a.deviation from the licensing basis for the plant.
For Browns Ferry, it appears that the unexpected amplifications in-structure response spectra are due to large amplifications through the soil and the structures, especially at high frequencies for the DG Building and the IPS.
In general,
- however, the staff contends that the use of the first method in the GIP-2 is only appropriate for facilities that do not.have in-. structure response spectra in their respective licensing basis documents.
The staff believes that the lack of specificity in the GIP-2 with regard to the selection of the appropriate method for determining equipment seismic
- adequacy, has led to the identified non-conformance.
The staff is pursuing this issue with the SHRUG Steering Group.
SITE AUDIT The NRC team observed the licensee's SRT performing a "walkdown" of the following equipment items:
1.
CAD Inserting System Panel, 2-PNLA-009-0054 and,0055 (Line.Nos.
9064 and 9065).
2.
Control Bench Board,. 2-PNLA-009-0003A and B (Line Nos.
9040 and 9041).
3.
Diesel Generator
- Panel, 3-BDGG-254-0003C, (Line No. 39003).
4.
Batteries, 3-BATB-254-OOOOC (Line No. 39002).
5.
'Battery Charger.,
3-CHGR-254-OOOOCB (Line No. 39004).
il
6.
8.
Hotor Control Center, 3-BDBB-219-0003EB (Line No. 39005).
Hedium Voltage Switchgear, 3-BDAA-211-0003EC (Line No. 39001).
Pump-LPCI MG Set 3DN (Line No. 39015).
9.
Transformer, 3-XFA-231-TS3B.(Line No. 39006).
10.
RCIS Auxil:iary Panel, 2-LPNL-029-0031 (Line,.No. 9074).
11.
Accumulator Tanks, O-TNK-086-0651A.
12.
Low Voltage Switchgear, ARD-2H-BKR.
13.
14.
15.
480V Reactor HOV Board (Line Nos.
39007 and 39008).
Horizontal Nitrogen Tank for Containment Atmosphere Dilution System.
RHR Service Mater Vertical
- Pump, O-PAP-023-0015-01.
In general, the audit team noted the following:
1.
The SRT was observed to take notes on the as-built configurations of equipment (e.g., overall dimensions),
open cabinet doors in some instances to visually inspect the internals, verify anchorage, and check potential spatial interactions.
2.
The information needed in the field for verification of seismic adequacy of equipment according to the GIP-2 approach was typically more than what was collected by the SRT during the walkdown that the NRC team observed.
,Verification of mounting of essential relays is an example (additional examples are included in Appendix A}.
Of course, it is possible that the. SRT either had collected the needed, information in prior walkdowns"or planned to collect in subsequent additional walkdowns.
Equipment-specific observations are included in Appendix 'A.
SNNRY AND CONCLUSIONS The licensee's SRT members were observed to be well qualified and organized for the seismic walkdown."
-.In general, they. were found to follow the GIP-2
,criteria.
The staff has noted certain equipment specific observations that are discuseed in Appendix "A."
However, the licensee is not required to separately respond to these observations.
It is expected that these observations will'e addressed and resolved in the licensee's final evaluations.
In regard to the selection of the appropriate method to determine equipment seismic adequacy concerning seismic capacity compared to seismic
- demand, the staff finds the use of the first method in GIP-2 inappropriate in that it underpredicts the seismic demand for certain equipment as defined by the licensing basis in-structure response spectra.
The staff believes the deviation was the result of inappropriate guidance in the GIP-2.
The
il
potential inconsistency between the GIP-2. alternatives for determining equipment seismic adequacy and the licensing basis in-structure response spectra will 'be pursued with the SHRUG Steering Group.
REFERENCES I.
Generic Implementation Procedures,
'Revisi'on 2 (GIP-2), Seismic gualification Utilities Group (SHRUG), February 14, 1992.
2.,
U.S.
'NRC Supplemental Safety Evaluation Report No.
2 on Generic Implementation Procedure, Hay 22, 1992.
il 0
, ~
APPENOIX A AUDIT ITENS AND OBSERVATIONS The audit team observed the licensee's SRT perform the walkdown of several equipment items.
A brief description of each item and observations of the licensee's walkdown for the items are provided below.
The licensee is not required to separately respond to these observations.
It is expected that these observations will be addressed in the licensee's final evaluations.
1.
2-PNLA-009-0054 and 0055 (Line Nos.
9064 and 9065)
This was identified as a
CAD inser ting system, panel which is basically a
two-bay vertical panel bolted sidewise and mounted on an embedded channel.
This item was for Unit 2 and'as stated to be similar to that for Unit 3.
The SRT performed the walkdown following the GIP-2 procedures.
There were several sources for potential interaction or impacting with other components as listed below:
A cabinet on one side and CRT monitors on, the other side.
2.
Potential rattling that can affect relays in the panel.
In addition, the mounting details could not be observed well to verify the adequacy and conformance of mounting, with available drawings.
2-PNLA-009-0003A and B (Line Nos.
9040 and 9041)
This is one bay of the horseshoe-shaped control bench board.
The panel was bolted to the adjacent bays.
The SRT verified the mounting, with plates and welds and noted some of the following concerns:
A bundle of cables was sagging inside the, cabinet apparently due to a missing support.
(This condition existed for at least another bay.)
The center pins of the rear door were missing creating a potential for rattling.
A long instrument was overhanging within the cabinet by about 20 inches.
The licensee stated that this instrument was shake table tested.
Verification of test data was not performed during the audit.
3.
3-BDGG-254-0003C (Line No. 39003)
This is a wall-mounted diesel generator panel containing switches, fuses and breakers.
The audit.team identified the following observations, which were also noted, by the SRT:
Ol
~
The vertical clearance between the panel and the supporting wall was uneven.
(The concern is the effectiveness of mounting.)
~
A large damper-like component was located above the panel creating a potential for interaction.
~
The depth of the panel may exceed the GIP-2 limit.
4.
3-BATB-254-OOOOC (Line No. 39002)
The batteries for the diesel generator were l.ocated on stepped racks in one corner at elevation 565 feet of the Diesel Generator Building.
The SRT verified the GIP-2 caveats including the spacers between battery cells.
The fo11owing concerns were noted by the audit team:
Structural adequacy of, the racks appeared questionable, however.,
some structural calculations to support its adequacy may exist.
~
Potential fall of a duct/damper
.above the batteries.
5.
3-CHGR-254-OOOOCB (Line No. 39004)
This is a wall-mounted battery charger panel.
The SRT performed the inspection including visual examination of the mounting.
It was stated that a similar charger was shake table tested.
The similarity of this item with the tested specimen may be used'or demonstration of equipment seismic adequacy.
6.
3-BDBB-219-0003EB (Line No. 39005)
This is an eight-bay free-standing motor control center manufactured by General Electric (GE).
The SRT verified the GIP-2 caveats.
The following observations were noted by the audit team:
~
The thin sheet metal of the HCC enclosure was bent inward for connecting to the base channel with a screw at each corner of each bay.
The flexibilityof the connection and stripping of the screws may be of concern.
~
The seismic capacity of the HCC may exceed the demand at the location.
7.
3-BOAA-211-0003EC (Line No. 39001)
This is a 13-bay GE 4-KV switchgear.
The SRT was observed checking mounting and taking notes.
The following observations were noted by the audit team:
Existence of an unusual eccentrically located swinging box on top of switchgear.
Potential for rattling of panels containing relays.
IS II IP
~ ~
8.
9.
10.
LPCI HG Set 3DN (Line No. 39015)
This pump-motor assembly mounted on a common skid is located in the Reactor Building at an elevation of 621 feet.
This is a commonly used equipment item.. The SRT performed the walkdown following the GIP-2 criteria.
The audit team observed possible interaction of a thin pipe line (about 3/4 inch diameter) which extended from the assembly.
3-XFA-231-TS3B (Line No. 39006)
This is
- a. 4KV/480V transformer manufactured by BBC.
The installation arrangement for this equipment was unusual with a heavy I-beam skid but the transformed was apparently unconnected in the extended front part.
Also, there was a block wall next to the transformer and another interaction potential.
The SRT noted all these installation conditions.
The coil support of the transformer:
could not be verified.
Equipment-specific,test data may exist.
2-LPNL-029-0031 (Line No. 9074)
This is an RCIS auxiliary panel.welded to the skid.
The panel houses many relays. including GE HGA which has been designated as a "Bad Actor" relay.
There. was a duct above the panel but its supporting conditions were not clear.
The SRT noted the duct but probably did not note the HGA,relay since it might have been beyond their charter.
Rear doors were very loose when closed and the potential banging is a concern.
0-TNK-086-0651A 12.
These are diesel generator accumulator tanks stored in framed structures from the ceiling in the Diesel Generator Room.
Cross-bracings were provided for stiffness of the steel frame.
Rod straps were used for an'choring the tank to the frame.
It was stated that probably not all of the tanks were safety related.
3-BDBB-231-0003B (Line No. 39007, 4&OY SD Board 3B)
This is a
GE low-voltage 8-section switchgear with cables and conduits entering from the top.
There was a moveable hoist on top of the switchgear.
The SRT indicated that a walkdown data package was completed for this. item.
13.
480V Reactor HOV Board (L'ine No. 39008)
This is a 20-section panel screwed to the base channel which is welded to embedded steel.
The sheet metal and screws at the connection
,resulted, in an undesirable flexible -anchorage.
Therefore, it was identified as an outlier according to the GIP-2.
i~
~ e I
14.
Nitrogen Horizontal Tank for Containment Atmosphere Dilution System This is a horizontal tank. supported by two skirts.
A cantilever.
panel is connected on one end of the tank.
The bolts connecting the skirts to the concrete were not properly engaged in the nuts.
15.
RHR Service Mater Vertical Pump (0-PMP-023-0015-01)
This is an outdoor.GE RHR service water pump mounted on a pedestal.
The anchorage between the, pedestal and the concrete
- below, as well as the effects of long unsupported piping on the pump performance under seismic loads appeared questionable.
ll l,t Ib
SBSNIC CAPACAYVS SBSMIC DKIIAND 'ygmy, gg~~~><
SPECTRA CoilPARlSON FOR OG ANO IPS BLOG 5% ONl G
1.5 X 80UNDlNG St%CYRUN PlG 4-2 DF GlP) VS I%8TRlJGTIJRE SSE RESPONSE O.GELT S.0KL SM
. D.O KLSee
~
~
~
~
~
~
~
~
~
'tkOS. SQ I
~
~
~
~ ~
1$ X80lNONOSPRCNVN
~ ~
~
r
~
~
~
~
~
~
~
~I
~
~
~
~
~
~
~
~
~
~
r
~
~
0.5 r
0 0
10 15 20 25 30 FREQUENCY NZl kOTE: REFER FlGURE FNS-4S, 8+$4.0,F~S.6, FHS4.1, ~W+.6 OF ilANSREPORT FOR lk-STRUCTllRE RESPONSE SPECTRA IDG BLDG UHBROAOENH)SY 05%IIPS UkSROAOENEO.SY 10%)
~i y ~ li
Richard Wessman However, the audit team, noticed some potential concerns in the areas of interface between different disciplines, some of the personal judgements exercised by the licensee.'s engineers or its contractor, and the use of industry guidelines that were not reviewed and approved by the staff.
During the audit, the staff identified a technical concern with the use of GIP-2 criteria by the licensee regarding the alternative methods for the comparison of seismic demand with the seismic capacity for equipment installed in the plant.
The technical details of the concern are described in Attachment 2 under the heading of "Response Spectra."
The staff conveyed the concern to TVA at the Browns Ferry audit exit meeting, and informed the SHRUG Steering Group of the potential generic impact through the representative of the MPR Associates at the meeting.
The issue is being discussed between the staff and the SHRUG Steering Group.
Attachments:
l.
Attendance Lists 2.
Audit Report Distribution:
qCentral
.F..i.l,esi NRC PDR EMEB RF/CHRON AThadani Bsheron Glainas Gbagchi Rrothman RPZimmerman SAVarga JFStolz Ddorman
".see previous concurrences JWilliams DOCUMENT NAME: G:-iCHENiBRSTRIP.696 To receive a copy of th'is docunent, indicate in the box C=copy w/o attachment/enclosure E=Copy with attachment/enclosure M = Ho co y OFFICE EMEB:DE*.
ECGB:DE*
EMEB:DE
'AME DATE PYChen 6/06/96 YKim
- Kmanol, 4/~/96 6/07/96 OFFICIAL RECORD COPY
Ii 41
~0 1I CI
~I