05000456/FIN-2008008-01
From kanterella
Revision as of 19:36, 20 February 2018 by StriderTol (talk | contribs) (Created page by program invented by StriderTol)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Finding | |
|---|---|
| Title | |
| Description | The inspectors identified an unresolved item (URI) concerning seismic Category I pipe supports associated with the safety injection (SI) and residual heat removal (RH) piping systems. Design documents for the 2SI06 and 2RH01 piping subsystems pipe supports were not sufficiently detailed to demonstrate compliance with the American Institute of Steel Construction (AISC) Manual of Steel Construction Code and the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. Description: The SI and RH piping systems are part of the emergency core cooling system (ECCS). The Braidwood Updated Final Safety Analysis Report (UFSAR), Section 6.3.1, stated the primary function of the ECCS is to remove the stored an
fission product decay heat from the reactor during accident conditions. The ECCS also provides shutdown capability for design basis accidents by means of boron injection. The ECCS was classified as a safety class II system designed to meet seismic category I requirements. The inspectors reviewed Calculation BRW-97-0827-M, Piping Evaluation for Lead Shielding Installation on Subsystem 2SI06 Piping per Temporary Lead Shielding Request (TSR) No.95-153, 96-018,96-045, 96-053, and 97-120, Revision 0 and Minor Revision 0A. The purpose of Revision 0 was to evaluate the affect of the temporary lead shielding installed on the 2SI06 piping subsystem (i.e., lead shielding installed on sections of pipelines 2RH01BA-12, 2RH01BB-12, 2RH01CA-16, 2RH01CB-16, 2SI06BA-24, and 2SI06BB-24) by the TSRs. The purpose of Minor Revision 0A was to evaluate the affect of converting the temporary lead shielding to permanent lead shielding. In addition, Minor Revision 0A identified that based on recent industry concerns the lead shielding weighed up to 10 percent more than was previously analyzed. Pipe stresses were determined from loads and load combinations due to internal pressure, pipe system dead weight, pipe thermal expansion and seismic excitation. The 2SI06 and 2RH01 piping subsystems were designed to the ASME Boiler and Pressure Vessel Code,Section III, Subsection NC and ND, 1977 Edition up to and including the 1979 Addenda. The associated pipe supports were designed to the AISC Manual of Steel Construction Code and the ASME Boiler and Pressure Vessel Code,Section III, Subsection NF, 1977 Edition through Summer 1979 Addenda. The seismic response spectra analysis of the piping subsystem was analyzed using the ASME Code Case N-411, Alternative Damping Values for Seismic Analysis of Classes 1, 2, and 3 Piping Sections,Section III, Division 1. As specified in the licensees UFSAR, Section 3.7, Table 3.7-1, Damping Values, the ASME Code Case N-411 may be used for alternative damping values when NRC conditions as defined in Regulatory Guide 1.84, Design and Fabrication Code Case Acceptability ASME Section III Division I, Revision 24 are met. In Calculation BRW-97-0827-M, Revision 0, the licensees qualification of the pipe supports were based on their review of Calculation 13.2.29, Structural Calculation for Mechanical Component Support [Pipe Support Number], Revision 2 and the use of engineering judgment. The licensee concluded that sufficient margin existed in the pipe support design such that the supports would be able to withstand the increased loads from the installed lead shielding. The inspectors reviewed the Structural Calculation for Mechanical Component Support [Pipe Support Number] contained in Calculation 13.2.29, Revision 2, for the following: Pipe Support Number Pipe Support Number Pipe Support Number 2SI06309X 2SI06328X 2SI06342X 2SI06310X 2SI06335X 2SI06345X 2SI06311G 2SI06336X 2SI06351X 2SI06316X 2SI06337X 2SI06358X 2SI06318X 2SI06340S 2SI06360X The inspectors determined that the engineering judgment used in Calculation BRW-97-0827-M, Revision 0 was not valid and the aforementioned pipe supports could exceed their design basis and operability acceptance limits. Also, a condition specified in ASME Code Case N-411 stated This Code Case is not appropriate for analyzing the dynamic response of piping systems using supports designed to dissipate energy by yielding. The licensee initiated issue report (IR) 00816677, NRC MOD/50.59 Inspection - 2SI06 Piping Subsystem Support, dated September 11, 2008, to address this issue. In response to IR 00816677, the licensees prompt operability determination concluded through analysis that the fillet weld connection between the attachment plate and the embedment plate for pipe support 2SI06316X exceeded design basis and operability limits. Subsequently, the licensee performed a walkdown to field verify the actual fillet weld size of this connection. The actual fillet weld size was determined to be 7/16 thick, which was greater than the 1/4 thick fillet weld size used in the analysis. The licensee determined that the pipe support 2SI06316X fillet weld connection exceeded the design basis limits but was within operability acceptance limits. Further analysis by the licensee showed pipe supports 2SI06328X, 2SI06340S, 2SI06345X and 2SI06358X exceeded their design basis limits. The concrete expansion anchor bolt evaluation for each pipe support resulted in a factor of safety of less than four but greater than two. A factor of safety of greater than two satisfies the operability requirements specified in procedure OP-AA-108-115, Operability Determinations (CM-1), Revision 6. Pipe support 2SI06318X was determined to have no margin for design basis acceptance limits and pipe support 2SI06337X had minimal design basis margin remaining. The licensee determined that the pipe supports 2SI066309X, 2SI06310X, 2SI06311G, 2SI06335X, 2SI06336X, 2SI06342X, 2SI06351X and 2SI06360X met design basis and operability acceptance limits. This issue is considered unresolved pending the licensees response to address the inspectors request for additional information (RAI) regarding the following inspectors concerns: ?F?nThe licensees prompt operability determination was made without incorporating the additional 10 percent weight and installed locations of the temporary lead shielding identified by Calculation BRW-97-0827-M, Minor Revision 0A into the licensees pipe stress computer analysis program. These changes have the potential to affect all pipe supports and anchors on the 2SI06 and 2RH01 piping subsystems. ?F?nThere are approximately 58 pipe supports and five pipe anchors associated with the 2SI06 piping subsystem, which were not verified to determine their design basis acceptability. ?F?nPipe supports and anchors for the 2RH01 piping subsystem were never verified to determine their design basis acceptability. ?F?nA condition specified in the ASME Code Case N-411 states When used for reconciliation work or for support optimization of existing designs, the effects of increased motion on existing clearances and on line mounted equipment should be checked. This condition along with the other four ASME Code N-411 specified conditions were not addressed in the pipe stress analysis for either the 2SI06 or 2RH01 piping subsystems. At the end of this inspection, the licensee stated that the SI and RH piping systems pipe stress computer analysis program would be revised to reflect the RAI concerns and the results provided to the NRC for review within three months of September 12, 2008. (URI 05000457/2008008-01(DRS) |
| Site: | Braidwood  |
|---|---|
| Report | IR 05000456/2008008 Section 1R17 |
| Date counted | Sep 30, 2008 (2008Q3) |
| Type: | URI: |
| cornerstone | No Cornerstone |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.17 |
| Inspectors (proximate) | B Dickson A Garmoeb Josec Scott D Hills G Hausman J Bozga |
| INPO aspect | |
| ' | |
Finding - Braidwood - IR 05000456/2008008 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (Braidwood) @ 2008Q3
Self-Identified List (Braidwood)
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||