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| {{Adams
| | #REDIRECT [[05000346/LER-1980-091-01, /01T-0:on 801223,during Analysis Per IE Bulletin 80-11,design for Block Wall Between Control Room & Stairway AB-1 Found to Be Less Conservative than Assumed in Fsar. Caused by Outdated Analytical Const Methods]] |
| | number = ML19347D947
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| | issue date = 04/10/1981
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| | title = /01X-3:on 801223,analysis of Concrete Walls Per IE Bulletin 80-11 Determined That Some Walls Would Be Overstressed During Seismic Event.Caused by Change in Analytical Methodology Since Walls Were Designed
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| | author name = Mekbel C
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| | author affiliation = TOLEDO EDISON CO.
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| | addressee name =
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| | addressee affiliation = NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
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| | docket = 05000346
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| | license number =
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| | contact person =
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| | document report number = IEB-80-11, LER-80-091-01X, LER-80-91-1X, NUDOCS 8104140515
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| | package number = ML19347D941
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| | document type = LICENSEE EVENT REPORT (SEE ALSO AO RO), TEXT-SAFETY REPORT
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| | page count = 4
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| }}
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| {{LER
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| | Title = /01X-3:on 801223,analysis of Concrete Walls Per IE Bulletin 80-11 Determined That Some Walls Would Be Overstressed During Seismic Event.Caused by Change in Analytical Methodology Since Walls Were Designed
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| | Plant =
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| | Reporting criterion =
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| | Power level =
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| | Mode =
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| | Docket = 05000346
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| | LER year = 1980
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| | LER number = 91
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| | LER revision = 1
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| | Event date =
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| | Report date =
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| | ENS =
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| | abstract =
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| }}
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| =text=
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| {{#Wiki_filter:* S. NUCLEAR REGULATORY COMMISSloN NRC P 'j 366
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| '"# d
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| * LICENSEE EVENT REPORT CONTROL BLOCK: l l
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| l l
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| lh (PLEASE PRINT CR 1.*SE ALL REQUIRED INFORMATION) 1 6
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| 's 8 9 LICENSEE ", ODE 14 15 LICENSE NUMBEH 2b 26 LICENSE TYPE JO bl CAT 68 CON'T.
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| l L l@l 0 l 510 l 10 l3 l416 @l1 l2 l2 l31810 l@l 014] 11018111@
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| "E O O 1 3o n 7
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| 8 60 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h Q]l (NP-32-80-17) The analysis of concrete block walls required by NRC IE Bulletin 80-11 l ggl determined that during a seismic event:
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| : 1) the wall between the control room and l
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| EBl stairway AB-1, 2) The floor beam at the top of wall 3307, 3) the connection between wall 2047 and the floor, and the floor beams attached to the top of the walls 3167 l
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| Epl kpI and 3187 would be overstressed. Walls 3167, 3177 and 3187 would also be overstressedl
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| {]l by compartment pressurization originating from a main feedwater line break in the l
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| These conditions are reportable per Technical Specification 6.9.1.8.1.
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| l ggl room.
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| C DE CODE S BC E COMPONENT CODE SUBCOdE S
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| O 9 7
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| 8 9
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| 10 11 12 13 18 19 20 SEQUENTIAL OCCURRENCE REPORT REVISION LER/Ro EVENT YEAR REPORT NO.
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| CODE TYPE NO.
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| ,,_ 21 22 23 24 26 27 28 29 30 31 32 KN A T ON O PL NT ME HOURS SB IT D FOR B.
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| SUPPLIE MANUFACTURER d@] Fl@
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| 34 3b M
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| 31 40 41 42 43 44 47 33 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h lTTOl l The cause is a change in the analytical methodolony used by the architect /eneineer I
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| i i l since the walls were desinned in the early 1970s. Usine the methods annifenhin ne I
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| l that time, the stresses would be acceptable. However, the change in methods results l
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| , 7 t
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| g l in a dynamic instead of a static analysis. Facility Change Requests 80-277, 81-015, l 81-016 and 81-018 have been written to make the necessary modifications.
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| l ggl 80 7
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| 8 9 ST
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| % POWE R OTHER STATUS DtS O Y
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| DISCOVERY DESCRIPTION NA l
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| l D l@l NRC IE Bulletin 80-11 l
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| W@ l 0l 5] 5l@l i s A TIVITY CO TENT RELEASED OF RELE ASE AMOUNT OF ACTIV:TY LOCATION OF RELEASE NA l
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| l NA l
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| @ l Zl@l 1 6 PERSONNEL ExPOSMES NUYeER TYPE
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| ==DESCRIPTION==
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| l 0 l 0 l 0 [@l Z l@l NA l
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| i 7 PERSONNE L INJUHIES OESCRIPTION@
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| NuveER l 0 l 0 l 0 l@l NA l
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| i a 80 7
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| 8 9 11 12 LOSS OF On DAMAGE To FACILITY TYPE
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| ==DESCRIPTION==
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| LZj@l NA l
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| i 9 80
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| 8 9 10 NRC USE ONLY ISSUE
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| ==DESCRIPTION==
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| Q hlNA l
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| l l l l l. l l l l l l l l j 58 SS 80 8104140 gly a
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| <3 to (419) 259-5608 DVR 80-211 NAME OF PREPARER PHONE:
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| TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-32-80-17 3l DATE OF EVENT: December 23, 1980, February 17, March 10, and March 27, 1981 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Floor beam at the top of concrete block wall 5107, the floor beam at the top of concrete block wall 3307, the connection between con-crete block wall 2047 and the floor and floor beams at the top of walls 3167 and 3
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| 3187 would be overstressed during a design basis seismic event. Walla 3167, 3177 and 3187 would be overstressed during a compartment pressurization.
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| Conditions Prior to Occurrence: The unit was in Mode 1 with Power (MWT) = 1525 and Load (Gross MRE) = 489.
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| Description of Occurrence: While performing the analysis of concrete block walls required by NRC IE Bulletin 80-11, it was determin'ed that during a scismic event the block wall between the control room and stair AB-1,would cause the floor beam above to be overst,ressed. This floor beam is attached to the wall and supports a portion of the floor above the control room.
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| It was determined that tuis condition was less conservative than assumed in the
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| ~
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| Final Safety Analysis Report (FSAR) and is being reported under Technical Specifi-cation 6.9.1.8.1.
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| The NRC On-Site Inspector was notified at 0925 hours on Decem-ber 23, 1980.
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| Additional analysis per NRC IE Bulletin 80-11 determined that during a seismic event the block wall between component cooling water heat exchanger and pump room (#328) and elevator number 2 would cause the floor becm above to be overstressed.
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| This floor _ beam is attached to the wall and supports a portion of the floor above the component cooling water exchanger and pump room.
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| It was also determined that this condition was less conservative than assumed in the FSAR and is being reported under Icchnical Specification 6.9.1.8.1.
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| The NRC On-Site Inspector was notified at 0935 hours on February 18, 1981.
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| Additional analysis per NRC IE Bulletin 80-11 determined that during a seismic event, the loads on block wall 2047 (between the two makeup pumps) from the attached piping systems would cause the stresses in the connection between the wall and the floor to be greater than code allowables.
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| It was determined that this condition was less conservative than assumed in the FSAR and is being reported under Technical Specification 6.9.1.8.i.'
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| The NRC On-Site Inspector was notified at 1221 hours on March 11, 1981.
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| Analysis of additional walls per NRC IE Bulletin 80-11 determined that during a seis-mic event, walls 3167 and 3187 would cause the floor beams attached to the tops of 3
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| these walls to become overstressed.
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| It was also determined that the concrete masonary in block walls 3167, 3177, and 3187 would be overstressed when subjected to compart-ment pressurization originating from a pipe break. These walls form a cable chase in Mechanical Penetration Room #4 (Room 314) on the 585 foot elevation.
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| LER #80-091
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| o TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-32-80-17 PAGE 2
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| +
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| This condition was less conservative than assumed in the FSAR and is being reported 3
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| under Tec.hnical Specification 6.9.1.8.1.
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| The NRC On-Site Inspector was notified at 1325 hours on March' 30, 1981.
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| Designation of Apparent Cause of Occurrence: This finding is due to a change in the analytical methodology used by the architect / engineer since the walls were designed in the early 1970s. Using the methods applicable at that time, the floor beam would be acceptable as built. However, the change in the method treats wall section prop-erties and seismic floor response inputs differently and is a dynamic instead of static analysis. Under the new methods, the floor beam design and the wall to floor connection is deficient.
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| Compartment pressures generated by postulated pipe breaks were not originally con-sidered when the architect / engineer designed the walls.
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| Re-analysis of these walls 3
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| with the additional loading has resulted in the overstressed masonary condition.
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| Analysis of Occurrence: There was no danger to the health and safety of the public or to station personnel. The floor beams and wall to floor connection in question are only overstressed during a maximum probable earthquake.
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| During all other pos-tulated unit operating conditions, the stresses are within allowables.
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| A preliminary review of the portion of the floor above the control room supported by this beam has been made. The results are not conclusive but indicate there is a potential that.1 portion of the floor above may undergo some structural distress.
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| A more detailed enalysis would take three months to perform. The modification to correct this condition consists of two small struts which could be installed in about two weeks. Therefore, in the interest of taking the most expeditious approach, Toledo Edison has decided to make the modification at this time without proceeding with further analytical effort.
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| Similarly, a preliminary review of the portion of the floor above the component cool-ing water heat exchanger and pump room supported by the beam has been made. The results are not conclusive but indicate there is a potential that a portion of the floor above may undergo some structural distress. A more detailed analysis would take three months to perforn. The modification to correct this condition consists of the installation of three plate stiffeners between the web of the floor beam and the floor above. This modification can be made in a shorter time than it would take to complete the detailed analysis of the floor. Therefore, in the interest of taking the most expeditious approach, Toledo Edison has decided to make the modi-i fication at this time without proceeding with the detailed floor analysis.
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| 1 Pipe supports 31-HCC-5H5, 31-HCC-5H6, 31-HCC-5H7 and 31-HCC-5H9 are attached to wall 2047. During a maximum probable earthquake these pipe supports impart loads to wall 2047 which causes the stresses in portion of the connection between wall 2047 and the floor to be greater than allowed by the Uniform Building Code (UBC) and American Concrete Institute (ACI) Code.
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| The wall was analyzed as five wall strips. The stresses in the connection between the wall and the floor in only two of the wall strips were greater than allowable. However, even in these two strips, the factors of safety ate greater than one, demonstrating that these strips are still stable.
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| l LER #80-091
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| TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-32-80-17 PAGE 3 There is also,an inherent conservatism in our analysis since the interaction betaeen wall strips is' not considered.
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| The piping systems attached to the wall have been re-analyzed assuming that there will be deflection in wall 2047. The resulting piping and support stress are all within the interin allowable stresses developed for IE Bulletin 79-14.
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| Overstressofthem$sonarycomprisingblockwalls 3167, 3177, and 3187 is due to the postulated compartment pressure resulting from a break in the main feedwater line in room 314. During all other operating conditions, the stresses are within allowables. However, such a break in this room has a low probability of occurring.
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| The portion of the pipe meets most of the criteria established by NRC Branch Tech-nical Position MEB 3-1 to qualify as a "no break zone";
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| the exception being that 3
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| the piping was designed to ANSI B31.1 instead of ASME Section III, Class 2.
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| How-ever, the Toledo Edison procurement and installation specifications required the same material and installation documentation as is required under ASME Section III, Class 2.
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| The effects of the wall deflection caused by the seismic loads on nucicar oafety related conduit attached to these walls have been investigated and failure of the conduit will not occur. Additional analysis to determine if yielding of the floor beams would cause structural distress in a portion of the floor above would take approximately six months to perform, while a modification to ensure the condition is conservative can be made in a shorter time.
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| ==Corrective Action==
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| Under Facility Change Request 80-277, two struts were added to the floor beam above the wall between the control room and stairway AB-1.
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| This work was completed March 6, 1981.
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| For the second finding, three plate stiffeners will be installed between the beam and floor above, under Facility Change Request 81-015.
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| For the third finding, the condition will be corrected by removing. the pipe supports from wall 2047 and attaching them to the makeup pump room ceiling. This relocation work will be done under Facility Change Request 81-016 when station operating condi-tions permit.
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| For the fourth finding, the condition will be corra.cted by the addition of a two-layered internal bracing system to the cable chase formed by walls 3167, 3177, and 3187. The top layer of bracing will lower the floor beam stresses to allowable 3
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| limits by reducing the wall deflections. The lower level internal bracing will re-duce the masonary wall stresses (these caused by compartment pressurization) to within allowables. These modifications will be made under Facility Change Request 81-018 when station operating conditions permit.
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| Failure Data: There have been no previously similar reported occurrences.
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| LER #80-091
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| --s
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