ML030430490
| ML030430490 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 10/18/2002 |
| From: | Monwaki Y Pacific Gas & Electric Co |
| To: | Document Control Desk, Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation |
| References | |
| +sispmjr200505, -nr, -RFPFR, DIL-03-001, TAC L23399 | |
| Download: ML030430490 (51) | |
Text
Enclosure 1 PG&E Letter DIL-03-001 Sheet 1 of 1 LIST OF DIABLO CANYON ISFSI REFERENCE DOCUMENTS
- 1.
Inter-Company Communication from Y. Moriwaki and P. Tan, Geo Pentech to L.
Cluff, Pacific Gas and Electric, "Independent Check of Seismic Displacement Analysis ISFSI Slope Diablo Canyon, California, dated October 18, 2002.
- 2.
Intra-Company Memorandum from L. Fusco to J. Strickland, "Fire Protection Evaluation For HI-TRAC Vehicle Path", dated March 13, 2001.
GeoPentech October 18, 2002 Mr. Lloyd Cluff Pacific Gas & Electric Company 245 Market Street San Francisco, CA 94177
SUBJECT:
INDEPENDENT CHECK OF SEISMIC DISPLACEMENT ANALYSIS ISFSI SLOPE DIABLO CANYON, CALIFORNIA
Dear Mr. Cluff:
This letter presents the results of an independent check of the seismic displacement analysis (SDA) previously performed on the Diablo Canyon ISFSI slope as presented in the Diablo Canyon ISFSI Safety Analysis Report (PG&E, 2001).
The previous SDA was performed using a de-coupled Newmark-type sliding block procedure (NRC, 2001) using dynamic response from the elastic finite element analysis code QUAD4M (1994). The check SDA results presented herein correspond to the cases specified based on a telephone conversation with Dr. Joseph Sun and Mr. Rob White of Pacific Gas & Electric Company (PG&E) on September 27, 2002 and a follow up e-mail from Mr.
Rob White on October 7, 2002. The analysis was performed in general accordance with our e-mail proposal dated October 1, 2002. This letter report reflects the comments provided to us by Dr.
Joseph Sun and Mr. Rob White.
The check SDA performed by GeoPentech was based on information from the following sources:
- 1) PG&E web site (links provided to us in an e-mail from Dr. Joseph Sun on September 27, 2002)
"* PG&E DCPP ISFSI Safety Analysis Report'
"* Presentation material presented to NRC and its reviewer on April 11, 2002
- 2) An overnight package sent on September 27, 2002:
"* GEO.DCPP.01.25 -
information on QUAD4M Analysis with CD attachment
"* GEO.DCPP.01.31 -
information on claybed strength characterization
"* Data Report G -
information on soil laboratory test data
- 3) Information e-mailed to us by Mr. Rob White on October 1, 2002
- 4) Various phone conversations with Dr. Joseph Sun and Mr. Rob White during the course of the study.
I http://www.pge. com/OO6_news/diablocanyon/pdf/sarbinderO12502.pdf 2 http ://www.pge. com/006_news/diablocanyon/pdf/groundfmotionf.pdf http://www.pge.com/006-news/diablocanyon/pdf/properties.pdf http://www.pge.com/006news/diablocanyon/pdf/slope_stability.pdf 601 Parkcenter Drive. Suite 110. Santa Ana, California 92705 letterrepdiablocanyonisfsi-f Phone (714) 796-9100 Fax (714) 796-9191 Web Site geopentech corn
Mr. Lloyd Cluff Pacific Gas & Electric Company October 18, 2002 Page 2 SCOPE OF SERVICES Our scope of services (based on our e-mail proposal dated October 1, 2002, and slightly modified based on the October 7, 2002, e-mail from Mr. Rob White) consisted of the following:
- 1. Review pertinent parts of the materials provided.
- 2. Generate two FLAC analysis meshes one reflecting the Sliding Mass lb and the other reflecting the Sliding Mass 2c.
(Because of the complexity of the interface elements representing the locations of the clay beds, it was not practical to have a single mesh reflecting the two Sliding Masses.)
- 3. Perform one-dimensional SHAKE and FLAC analyses to set the analysis details and to specify the input ground motion for the two-dimensional FLAC analyses.
- 4. Develop material properties of the clay beds for FLAC analysis consistent with the laboratory test results and the SAR (PG&E, 2001).
- 5. Perform two sets of FLAC analysis, one for the Sliding Mass lb and the other for the Sliding Mass 2c, using the mass-proportional damping, the same "bi-linear" shear strength of the clay beds used in the previous UTEXAS3/QUAD4M analyses and presented in the SAR (PG&E, 2001), and for the input ground motions with positive and negative polarities.
- 6. Perform two parametric analyses for the Sliding Mass lb (using only the positive polarity) case: one using the full Rayleigh damping and the other using a shear resistance of the clay beds that has an initial "bump" (representing the peak strength of claybeds) higher than that specified by the bi-linear relationship (representing the post-peak strength of claybeds), but decreases with the amount of relative displacement to the value corresponding to the bi linear relationship (the "bump" case).
- 7. Provide this letter report summarizing the results of our analyses.
SOFTWARE The computer code FLAC, Version 4 (Itasca, 2001) was used to perform the check SDA. FLAC is a two-dimensional explicit finite difference computer program for geotechnical engineering and rock mechanics computations.
An analysis section is discretized just like in the finite element method using elements and nodes. The stress-strain properties of materials used in the analysis could be elastic to nonlinear plastic with degradation in stiffness and strength as a function of specified parameters.
The FLAC code simulates physical processes by solving the dynamic momentum equations with specified input loading conditions including seismic shaking at the compliant base of an analysis section. Specifically, for a postulated input seismic shaking, FLAC is capable of directly computing seismically induced deformation and displacement of soil-rock structure systems.
FLAC Version 4.0 has been qualified by the Department of Energy, Yucca Mount Project as documented in the following 2 reports:
Document
Title:
Software Definition Report for FLAC Version 4.0 Document Number: 10167-SDR-4.0-00 Letterrepdiablocanyonisfsi-f GeoPentech
Mr. Lloyd Cluff Pacific Gas & Electric Company October1 8, 2002 Page 3 Document
Title:
Software Implementation Report for FLAC Version 4.0 Document Number: 10167-SIR-4.0-00 INPUT The geometry of the ISFSI cut slope was based on Section I-I' (SAR Figure 2.6-18). Geometry of sliding mass lb and sliding mass 2c were based on SAR Figures 2.6-47 and 2.6-48, respectively and coordinates defining the failure surfaces were provided in the October I e-mail from Rob White.
Dynamic properties for the rock mass were based on Figures 6, 7, and 8 of Calculation Package GEO.DCPP.01.25.
Claybeds were modeled as interface elements in FLAC with strength corresponding to that shown on SAR Figure 2.6-50. Ground motion (Set 1) was used as the input time history for the FLAC analysis.
This set was selected because it produced the largest displacements presented in SAR Table 2.6-5. The digital record of this time history was provided on the CD included as an attachment to Calculation Package GEO.DCPP.01.25.
ANALYSIS Figures la and lb show the FLAC meshes used in the check SDA for the Sliding Mass lb and 2c, respectively. The locations of interface elements representing clay beds are shown in these figures using red lines while the boundaries for different material types are shown using blue lines.
Interface elements rather than "regular" elements were used in these meshes to model clay beds to allow displacement along clay beds. ("Regular" elements in FLAC, like any other similar computer programs representing analysis sections using discretized elements including any finite element programs, cannot excessively distort without generating numerical problems.) A compliant base was used at the base of the analytical model to allow absorption of outgoing waves. The material numbers shown in these figures correspond to the numbers used to identify different materials whose properties are presented in Table 1. The material properties summarized in Table 1 are consistent with Table 1 of GEO.DCPP.01.25.
The stiffness values for the Obispo Formation bedrock used in the check SDA reflected the effects of shaking levels based on one-dimensional SHAKE and FLAC analysis as well as the results of the previous QUAD4M analysis; the stiffness values were typically less than 10 percent lower than those implied by the shear wave velocity values listed in Table 1.
The meshes shown on Figures la and lb are coarser than that used in the previous QUAD4M analysis (GEO.DCPP.01.25). However, the results of one-dimensional left-side and right-side free field SHAKE and FLAC analyses indicate that the coarser mesh selected for FLAC is quite appropriate. Also, except for one parametric analysis discussed later, the FLAC analyses were performed using mass-proportional damping rather than a full Rayleigh damping that uses both mass-and stiffness-proportioned damping. This was done because full Rayleigh damping FLAC analysis of the sections shown on Figures la and lb takes more than an order of magnitude longer computation time than those using just mass-proportional damping. Based on the computed ground motions from the one-dimensional FLAC analyses we performed, the use of mass-proportional damping rather than full Rayleigh damping would produce slightly conservative results. Basically, Letterrepdiablocanyonisfsi-f GeoPentech
Mr. Lloyd Cluff Pacific Gas & Electric Company October 18, 2002 Page 4 the damping values used in the mass-proportional damping in FLAC analysis are in their effects somewhat lower than those used in the previous QUAD4M analysis, which did use full Rayleigh damping values. Low damping values would generally result in higher and thus more conservative responses and computed displacement results.
The free-field acceleration time history specified as the input motion at the ground surface is shown on Figure 2a.
In both the previous QUAD4M analyses and the current FLAC analyses, this free field ground motion was deconvolved using SHAKE to the base of the one-dimensional left-side free-field models and applied as "outcrop" motion at the base of the QUAD4M or FLAC mesh.
The acceleration time history shown on Figure 2b is the deconvolved outcrop motion from such SHAKE analysis, which subsequently was used as the "outcrop" input motion in our check FLAC analyses. The free-field motion shown on Figure 2a is identified as Set 1 motion in SAR Section 2.6.5.1.3.3 and Table 2.6-4 and 2.6-5, and Calculation Package GEO.DCPP.01.25 Figure 4. This ground motion was selected for the FLAC coupled analysis because it produced the largest seismic displacement using the Newmark-type sliding block de-coupled analysis procedure as summarized in SAR Table 2.6-5.
The FLAC input motion (shown on Figure 2b) has the positive polarity when applied to a FLAC analysis section with the positive input accelerations acting toward right (into-slope direction) of the analysis section and the negative polarity when the opposite (out-of-slope direction) is the case.
Although only the positive polarity is appropriate for the tectonic environment at the site (SAR Section 2.6.5.1.3.4), the results of our check SDA indicate that very similar displacement values were computed using either positive or negative polarity cases.
Figure 3a shows the "bi-linear" undrained shear strength of the clay beds shown in SAR Figure 2.6
- 50. The bi-linear undrained shear strength shown on Figure 3a was represented in the check FLAC SDA using a combination of friction angles and cohesion. It is our opinion that the shear strength shown on Figure 3a is rather conservative. The assumption of all the pertinent clay beds becoming sufficiently wet to reach the conditions imposed on the laboratory testing specimens is conservative to begin with. In addition, based on our evaluation of Data Report G, most of the claybed samples tested exhibited peak strength as the samples were strained. As sample strain continued, the strength dropped from the peak value to a "post-peak" strength, which is on average almost 30%
lower than the peak strength. Figure 3b shows the idealized variation of the ratio between the shear resistance of clay bed and its post-peak strength with various displacement levels. It can be seen from Figure 3b that at very small displacements, the shear resistance of clay bed is high, but as the displacement is increased, the shear resistance is reduced by almost 30% at a shear displacement of 6 inches.
The peak strength of the tested clay bed samples was conservatively ignored in the previous Newmark-type sliding analysis as presented in SAR section 2.6.5.1.2.3.
The ratio relationship shown on Figure 3b when multiplied by an appropriate post-peak shear strength value from Figure 3a results in a somewhat more realistic representation of how shear resistance in clay beds may vary with relative displacement. The "bump" in Figure 3b was developed based on the results of the laboratory direct shear tests provided. We note that on the basis of the documents provided to us the greatest conservatism in the SDA resides in the kinematic and material characterizations of the clay beds.
Letterrepdiablocanyonisfsf-f GeoPentech
Mr. Lloyd Cluff Pacific Gas & Electric Company October 18, 2002 Page 5 RESULTS OF CHECK ANALYSES The key results of our check SDA are summarized in the tables and figures contained in the Attachment to this letter as described below:
Sliding Mass lb Figure 4a shows a portion of the deformed FLAC mesh without any exaggeration for the positive polarity case involving the Sliding Mass lb; it is basically a blowup of the Sliding Mass lb area shown on Figure la because at this scale the relatively small computed displacements are not obvious. However, on Figure 4a one can identify a small gap behind the Sliding Mass lb as the sliding mass separates from the back slope and moves on top of the clay bed which was modeled as interface elements with low shear resistance. Figure 4a also shows relative displacement vectors indicating the sense of direction of the computed displacements.
Figure 4b shows absolute horizontal displacement time histories of the Sliding Mass lb and the slope mass (the slope materials beneath the Sliding Mass lb) and the relative horizontal displacement time history of Sliding Mass lb also for the case of positive polarity. The relative displacement time history shown on Figure 4b using red color was obtained by subtracting the absolute slope mass displacements from the absolute Sliding Mass lb displacements. Thus, the relative displacement time history represents how the Sliding Mass lb moves with respect to the sliding plane beneath it as a function of time. As shown on Figure 4b, the Sliding Mass lb moves horizontally by about 3 feet with respect to the slope under the postulated shaking conditions. The actual computed horizontal displacement value in this case is 3.1 feet as presented in Table 2.
Figures 5a and 5b show, respectively, the results similar to those shown on Figures 4a and 4b except they correspond to the case using the negative polarity input motion. As shown in Table 2, the computed horizontal relative displacement of the Sliding Mass lb in this case is also 3.1 feet. The results from the coupled FLAC analysis are consistent with the results from the de-coupled Newmark-type sliding block estimates of 3.1 feet using ground motion Set 1 as summarized in SAR Table 2.6-5.
Sliding Mass 2c Figures 6a, 6b, 7a, and 7b show, respectively, the results similar to those shown on Figures 4a, 4b, 5a, and 5b except they correspond to the case for the Sliding Mass 2c (Figure lb) rather than the Sliding Mass lb. As shown on Figures 6b and 7b and in Table 2, the computed horizontal relative displacements of the Sliding Mass 2c are 2.5 and 2.3 feet for the positive and negative polarity cases, respectively. The FLAC computed displacements are slightly less than the Newmark-type sliding block estimates of 3.1 feet for slide mass 2c using ground motion Set I as summarized in SAR Table 2.6-5.
Letterrepdiablocanyonisfsi-f GeoPentech
Mr. Lloyd Cluff Pacific Gas & Electric Company October 18, 2002 Page 6 Parametric Study of Mass-Proportional Damping In addition to the main analysis cases presented in Figures 4a through 7b, two cases of parametric analysis for the Sliding Mass lb using the positive polarity were performed.
The results are summarized in Table 2. The first parametric analysis addressed the mass-proportional damping issue. As noted before, the FLAC runs associated with the results shown on Figures 4a through 7b used only the mass-proportional damping rather than the full Rayleigh damping. To document the degree of conservatism inherent in this approach, the first parametric analysis case was run using the full Rayleigh damping. As shown in Table 2, the use of full Rayleigh damping consistent with the previous QUAD4M analyses results in the computed relative displacement of 2.5 feet for the Sliding Mass lb compared to 3.1 feet displacement computed for the case of mass-proportional damping.
Parametric Study of Strength Characterization of Clay Beds The second parametric analysis case addressed the case of an initial "bump" (incorporation of peak strength) in the shear resistance of the clay beds. This is the case using the less conservative shear strength characterization of the clay beds using the ratio relationship shown on Figure 3b. The computed relative displacement of the Sliding Mass lb under the positive polarity input motion was 2.6 feet. The conservative mass-proportional damping was used in this parametric analysis.
SUMMARY
AND CONCLUSIONS In summary, Table 2 presents the computed relative displacement values of the Sliding Masses lb and 2c under the various postulated conditions listed therein. On the basis of the results of the independent check SDA we completed and summarized in Table 2, we conclude that the results of the previous decoupled QUAD4M-based SDA likely are reasonable if not somewhat conservative for the characterized strength of the clay beds.
It is our opinion that the strength characterization of clay beds is the single controlling parameter for the numerical modeling to estimate seismically induced sliding mass movements during the postulated earthquake at the Diablo Canyon ISFSI slope. It is also our opinion that a more realistic shear strength of the clay beds reflecting the inter-locking effects induced by rock asperities along the thin clay beds can be developed. Such a shear strength model when incorporated into the coupled FLAC analysis would result in less conservative and more realistic estimates of seismically induced displacement of the sliding masses along the clay beds. The assumption that the clay beds are perfectly smooth to allow undeterred displacement along the beds without inter-locking and dilative effects caused by rock asperities regardless of how much movements have taken place is very conservative.
While the results of the coupled analyses presented herein confirm the reasonableness of the previously completed de-coupled analyses based on the Newmark sliding block procedure, the results from both methods should be considered conservative and the actual movements of any sliding masses at the ISFSI slope under the postulated earthquake shaking Letterrepdiablocanyonisfsti-f GeoPentech
Mr. Lloyd Cluff Pacific Gas & Electric Company October 18, 2002 Page 7 conditions should be less. The lack of geological evidence of movements of large rock masses at the site in the past 500,000 years as stated in SAR Section 2.6.5.1.3.6 validates this conservatism associated with the computed seismic diplacements.
LIMITATIONS The independent check analysis performed and the professional judgments presented in this letter report are based on the information PG&E provided to us and our general experience in geotechnical earthquake engineering.
GeoPentech does not guarantee the performance of the project in any respect, only that the engineering work and judgment rendered meet the standard of care of the profession at this time.
We appreciate this opportunity to be of service to you. If you have any questions or require additional information, please call us at your convenience.
Sincerely, GeoPentech Yoshi Moriwa Principal AssocPha T
Associate Attachments Letterrepdiablocanyonisfsi-f GeoPentech
Mr. Lloyd Cluff Pacific Gas & Electric Company October 18, 2002 Page 8 REFERENCES Geoscience Calculation Package GEO.DCPP.01.25, Revision 2, Determination of Seismic Coefficient Time Histories for Potential Sliding Masses Above Cut Slope behind ISFSI Pad. June 21, 2002.
Geoscience Calculation Package GEO.DCPP.01.31, Revision 1, Development of Strength Envelops for Clay Beds at DCPP ISFSI, June 25, 2002.
Data Report G, Soil Laboratory Test Data (Cooper Testing Laboratories), Diablo Canyon ISFSI, December 17, 2001.
Hudson M., Idriss I.M., and Beikae M., 1991. Quad4M (Program and User's Manual). Center for Geotechnical Modeling, Department of Civil & Environmental Engineering, University of California, Davis, California.
Itasca, 2001. Fast Lagrangian Analysis of Continua (FLAC) version 4.0 User's Guide and Manuals.
August 2001.
Idriss I.M., Sun J.I., 1991. User's Manual for SHAKE91, program modified based on the original SHAKE program published in December 1972 by Schnabel, Lysmer, and Seed, Center for Geotechnical Modeling, Department of Civil & Environmental Engineering, University of California, Davis, California. November 1992.
NRC, 2002. NUREG-1620, Rev. 1, Standard Review Plan for the Review of a Reclamation Plan for Mill Tailings Sites Under Title II of the Uranium Mill Tailings Radiation Control Act, Draft Report for Comments, prepared by U.S. Nuclear Regulatory Commission, Office of Nuclear Materials Safety and Safeguards, Washing D.C., January.
PG&E, 2001. Diablo Canyon Independent Spent Fuel Storage Installation Safety Analysis Report.
Schnabel, P.B., Lysmer, J., and Seed, H.B., 1972. SHAK, A computer program for earthquake response analysis of horizontally layered sites, EERC Report No. 72-12, University of California, Berkeley.
Wright S.G., 1991. UTEXAS3, A Computer Program for Slope Stability Calculations, Shinoak Software, Austin, Texas, 1991.
Letterrepdiablocanyonisfsi-f GeoPentech
ATTACHMENTS GeoPentech October 9, 2002 Iterpiboaynss-letterrepdiablocanyonisfsi-f
TABLE 1 MATERIAL PROPERTIES USED IN FLAC DYNAMIC ANALYSIS Slope Section I-I' DIABLO CANYON POWER PLANT Material Description Layer and Unit Shear Wave Poisson's No.
Thickness Weight Velocity Ratio (h)L I
(pcf)
(fps) 1 Obispo Formation 160 feet 140 4000 0.37 Bedrock 2
Obispo Formation 100 feet 145 4800 0.37 Bedrock 3
Obispo Formation Depth >260 150 5900 0.35 Bedrock feet bgs Note: 1 Thickness below horizontal ground surface in the left or right side free field shown on Figure 1.
TABLE 2
SUMMARY
OF FLAC ANALYSIS RESULTS Slope Section 1-1' DIABLO CANYON POWER PLANT Sliding Time Average Relative Remark Mass History Horizontal Polarity Displacement (feet) lb Positive 3.1 lb Negative 3.1 2c Positive 2.5 2c Negative 2.3 lb Positive 2.5 Using mass and stiffness proportional (Rayleigh) damping lb Positive 2.6 Using shear strength as a function of I relative displacment (Figure 3b)
- Note. Using mass proportional damping.
Clay bed modeled as interface between Sliding mass modeled sliding and slope masS as separate body from the slope mass Scale - feet I
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Right Side Free Field Figure 1: FLAC MESH DISCRETIZATION FOR SLIDING MASSES lb & 2c
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eUi -IT~
and2cskws don resto the Proposed site for th SS aiiy a
efre.thi w dowing identified several potential hazards that the HI-TRAC vihlCle myecwtrdrn h
mnovemen of spen fuel. -These hazards amredo~uffletjd in the walk dowrn'report as well as AIR A0524878.
Inadtioin to the MvaUat 0no theý transportiaolOi pt, Adacd Concepts. Inc; efre an vauaio fr hebuk hydrogen, strg tnslcted eas of the AuxlarBudigo
-Ie 115 ft.-elevation. 'As noted in Advanced Concep~ts' reprt Buk Hydrogen Facility Risk Evauat~n, (Atacliihit2) herisk to-tie HI-TRAC tranporte~r from ail explosion Or a msieis not considered risk si~gnificatit. -As~uh dacdCnet eemndta h hyroe tak onte15:.elevation would not pose a risk to the HI-TRAC vehicle.
If ou ee aditonal infornation or clarification on heabov topics. pleaseconatDv HL0*
at 805-
-4054.
'Cs F. F 1ý _ý
IEALATON it, l -lit-iRAC
- -'~~~TRIANSPOP.TAIU)N.tP March6. 20 Fir l~rars Fom u~iiaT Bud'fl To'ISFSI NIt
- n. rot.ornteUi A waZlk down of the primary andl alternate HI-TRLAC transpoflation Iot.fo teUi "and 2 cask washi down areas to the Proposed site for th-I.
.,ndep --
tSpent Fuel Storage
"--sta..tion (151-S-) and the cilit tsfer facility (CT.F) south of the Raw Water Storage Rsrors, was perfoired in early l-ebruary. 1001Ab members of the Fire Protection Grop (i~gneCifl).This walk dow was performed to detrmine potential fire hazards the HI-TRAC transportation vehicle, may encoun~ter during its mo~vement 'of spent fuel
-casrrott itfel pool area to the ISFSI site.-As shown on drawýing 401 6849,______
S..
Rev. A, ISFSI Facility
, Scton & Detail-" there are two routes available-to the
-I-TRAC vehicle. ThepimaP yo tewil be out Gati 20 and up Reservoir Rd. to the
-ISFSI sit*n h lent ro~ute will be in front of th anwrhouse (Building 115).
4-through pa~rkig lot 8 onto Reservoir'Rd to the ISFSI site. This evaluation'looked at both possible routes adpodes the fire ha e
uation for each. %Based on the hazards noted during this walk down an "nistrte procedure il beirequired todesur i plementation of the recommendations in this document priotth movement ofspe fuel. The development of this administrative procedure is-being tra~cked under'A/R
-A0524878.
For Unit IUtransportation of the spent fuel casks w11 commece from Fire Area 3R (Spent Fuel PooUniit 1) on the 115 ft. elevation. A survey of the area noted a
- .i--/-"-"
n~e5ai~yj n-rl 6f door' 361. While significant quantity of combustibles stored in the hallwayjust orth 4
- 2..-.
- 44- -
o;,
.4I-T A
DO f-9
-~
.4 4
4
.q
-..4 A.... I 44,4
EVALUATION (Fj 1HlE 1ll-TRAC
-TRANs-ORT ROUTE Marih 6 2001
-0.
th ~mbus~tl loading in rils wre is rnagiitUC ltlWvr thin the ctlmrbuibl.
loid used
°
- fi* tl l01tec (,alcuiaio Hl-2002512} a-ca !:._,!:,.*-*
- d g the aluation of a til-11RAC fuel..n.t..
n
- 2) s.
dent action thi s are* 'should b-'cleared of all combustibles for a distance of 20 f1 prior
- to the transportation of spent fuel throuhý,this area
.524878).
Outside of the cask wash down area along the east side-of the roadwa aelqiNtroge and Hydrogen
-tanks., Nitrogenf in a nonflamimablegas an does not pose a fire protection problem. The'
.ydrogen tanks, six(6).,
51 cubic feetach, are locaed in a seismically eval uted rack, s were -
for.potential risks en"close in seismincally evaluated vault Thes ealuated for t
to the HI-TRAC vehicle in the -Bulk Hydrogen Facility Risk Evaluation$' (Chron No
-- _236670) and determined to pose little threat tothe vehicle during the mov:emen.t of spent,:
Q fuel. As such, no furhe action is reuired herelfor this subject.
. Alongthe east side fthvehicleuta waste storage bunkers. While an nspection of the bunkers did:not rev.eal any significant fire protection h it would be
- .inspectiootebnesddnt*,
a
,,_-t.
action t°-. ensueallof the d°bu°kers are 6osd ort "transport. and the area is restricted from vehicles (A052487 8).
ForUnit 2, transportation of the spent fuel casks WIl commence from Fire Area 3W (spent Fiul Pool, Unit 2), on the 115 ft. elevation. A survey of the area noted few combustibles. However, like Unit I the hallway just south of door 261-2 is a storage area for cleaning supplies and radastc vacuums i*
equipment. While the quantity of items stored in the area is small a prudent action would be to clear all combustibles for a
-ItI.TRAC IX'-*-*2:
-5v,,
OA I
-. 5 O F-II I-IR,-
FErAIUA1 ION 0- iIIEII-RAC I RANSPORTATION ROUME
-Aarch6.200I Sdisac eofathkat.prtohe movCmeC o.t nt uel siiiar recommended for Unit I (A0S248" Q).
For Both Units.
S- " Continuing" w}ith the evluation of the route outside the Auxiliary Buildingn but still inside "te radiological-controlled area (RCA). on the west side just south of "the Primary WateStorage Tank (PWST) 2-i is a welding supply seatrain:. This seatrain pose-a *ire protectiOrn holds welding rod oven and otheruweditdg suppnsaaa
" "'i t A
-threai to the HI-TRAC vehicl. Outside this facility is a storage rack for Argon gas yli*ne*rs. Since theArgon gas does not preScnt a fire hazard no further fire protection evaluation is'being performed. In accordance with procedlureMA.1D
-Compress ed.-,
"s ldC ers a surely chained in a storag k
a vertical
- A
- 'Gas Cylinde CrtOn*l",thesecylind asto ar v
s c.:
misl hjjrtoth
-TA veie.
position. -As such, they should not present anymssile"hazardseto the H
ACehicl On the west side, south ofthe welding supply seatran it rage location for the portable crne.' This crane, while mostly metal, has a diesel el tank with an' approximate-capa city of 40 gallons. Because of the high flashpoint of diesel fuel and the fat that it is stored in a fuel ank it would not psert-a ire haz:ard tothe transport.
vehicle.
On th east side, just north of the radiological area fence, is a paint storage seatrain. This--,-,,
building is a storage facility for paints, thinners, cleanersetc. used in the palintinig efforts
'HI.TRAC DOC
-EVATTIA! ION til-ni l-IA 1 RANSPORTA IION Rot' zoo 1;
March
. 200 insie cthe RCA. lI'h,-% VwflbuiIbk' r 4"e nieamld~eta' ih.
ae
-- p,--.. h.......m. *...- uppr-ssion $%'Stemn Cuh thOupl e
ith the rcial tailht> being u d
to store t-e ha: arous materials should ensure thatrit doesn i pose a threat to the "1-I.TRAC vehicle.
Outside the RCA. just South of the south gate on thc 1 15 ft elevation is the staging ae for ful-and e-y
- as c--ylinder.. These as cylin derscontinnonflammable g-ssand -
" for full arid Thnesa
- c......-
ire placed -in i*til ageraksuntil they aare removed f6rF~ tumCto,-he w_.rehouk. Inside the Storage racks.the cylinders are-hainedtoensuretheydonofall over during transit or storage.
trice no flammable gasses are stored in-this ar.'-a.
--,pe.
DCMT-4,
'oxi
& xplSiveMtras and because the-cylinders that-ar stred in these rcsare secured in a vertical position they will not pos a fire or missile hazard to the HI.TRAc transportation vehicle..
~jypTransfc Route
-After leaving the RCA the primary rute for the HI-TRAC vehicle wil b suth toward Gate 20.-Hiading toward Gate 20 just north of the Unit 2 Cold Machine Shop (Building 116)1-at the 85 ft.'de laion, is a staging are for materials and PG&E Vehicles. From a oaspecthe highest h in his area is from the storage of one of the.two
'PG&E fuel storage tiucks. One of these trucks is normally parked at the maintenance facii y norheasof the ISFSI site wile t other is parked inside orjust outside the fa" facih northeastofhlF ite %ri the protected area.' Each of these fuel trucks has the capability of holding 2 all
.o I-T* o
- ."C 4-
INVA LUA1O(i IJI 1l-TR AC 11tANSPOR All()% ROUll f~e. Pesntl OlC I~h vhicc~is confiiguredt od 10 N1 0 gallLn fdcdfc n Tans ndStrae ass."Adusin fr hesc lng
- distance, ssngFince5o Departnlent
~
~
he ofteAmyTcnsa aulTM -00,gl 'sofncurs t Rsit heEfec of ccdnt al xlsos'
" dtdNvme190itwseeine tc that no damae stoedinths re.
s uc, o
d~iesioa fueqr nl a re reuied fo thed fuel truc st '
in thas arloera. A ta Foloigion th icalin setion toward0(6atev 20.!7tlhe Unim Ce~old Machine shoan four (4) lage usedtan r
eto h ITA oie npcino hs etan revald tatthee aciites er beit lng uetotreminteance euimnt sepie
- flins, exldng temsetbtnotahing tha wqould~ pose a hazard no the i-TaCe d
oteH-RCtransportation vehicle anditts cargo.
oee, tteen fteinie aproimatel strack n tis ab e&n~ sdi tr rpn yidr oyhlsue ntepat aka th tm o isecio asonyhaf ulwihamite r
ffl an emt cidrs.o butd thee s n asurnc tht hisraktold' be completely 2-ull d
when sp nt uli en moloven*d ow Assuh anclnew stoaelcation wilne ob on o h trg ftee cylndrs priore ston furcmvement (af th2H878
- o. In addition tof thse proane cyindes hazardC toC th H5T
-rage.
Thisi
S1.A...1 A-IO 00\\
l oi IJ-AC
'- 1R.NSPORiA1)ONROUIT
-W6 6'.,2001 ae.IfCand w tin daon th-J'-
a ol the" nit Ad machine shop. Whilce l-argon cylindie d n' Iea fire harird to theIlliRAC transort te cylndersmight. The 'c~ inderi are chainedansuruddba concrete block vall and in accordance uit) DCN T-40. it is accpal to store clen cylindcrs at this l i
Fu;49
-:evaluiation of this configuration 9 PC A in" Calculation M-1047. MnmilSaration lcwelAeyeeTnsadTase Bass ed on this evaUatio it as detrine htth ctlne'"nes trda tis location were acceptable c__
Pror w xtng th rtced area (throiigh Gate 0)a hazardous storage bul71 F2' "is located approximtely ft fro...d.
way just cast of.Gaie 20. Thisfiacility was stabishe to house paint,thinners, cleaners and other flammable materials uIsed int preartin aind painting 7proeses,at DCPP. This building is a fire rated stnacture and i's L Clasifid and Factory Mutulal Systems approved.-Because of the design ofth structurevan the intrl suppression systern this strucuewilntpsasgifat
-th the IH-TpAC transportation vehicle or its contents.-'
Outside Gate 20 is iiing lot6. During a norma! workweek this area is f11 of peronnel
,.vehiCles.Becaus of the largeinumberoft vehicles normally Parked in the are and t-h
- minimal amount of ime the HI-TRAC vehicle will spend traveling throug this area a, prbability risk assessment was performed. Based on this risk assessment it Was determined thatthe probability of a gas tank exploding nd c ing damage to
-. l.TRA C
6
-=
2
-EVAI t;A7I6N
- 111 t:lHI-A
-il-,LA-Thkic.. wa-mininial
- No PRAO 141. R' -0. -Pi.k A,,,;,fl1CflO ItD Cask/SpentFuel Tran~oUki' Wlthin 1Ihc 1"I)CM IIT ootiik
-1a'.
As such.4 vt _ iteht.eCxceftiOn of theadministratie actiýnsj nted in calculation PRAO 1
,1 no frther actons ame reqtwred.
In addition to pronlvehicles parked in parking lot 6 the PG&E fuel tUck is also stored in this area -Th
_ultk a tsown' desipae parking space appro imaey
'120 f--.*-rm the route of the Cvehicle route. An evaluation mms performed using
-:the:h.,,,ed in ocalulition M-l04C Rev. 0. Adjusting for the scaling distac using to Fig. 2.15 of DepLUiýrnet of the Army Technrical Mainual TM 5-1300. it was dtrine that no -danmage would occur to the tIl-TRAC vehicle with the fuel truck stored on adito acion we*uirdfo thestoageof the fuel
-_tI this Tocation. Asuch, n arui the l
truck( at this location.
rthe Hi-TRAC ve"c"e leaves prkinglot 6 it will tavel up Shore Cliff Rd. toward the ISFSI site. Along Shore Cliff Rd. the-HI-TRAC ve.hicle will pass by ft hazardous w-ste facility (Building 120). This facility is ocat m the road and houses "hazrdos wst*ein 55
.dru*m*s for ýhipmrent offsite. This facili u
p
- ire ha.dto the HiTRAC velhicle.
J The Hil-TRAC ehle ill then turn onto Reservoirrd. and pas by Wahous B (Building-113)andt firing range (Building 114). Warehouse B is approximately 75 ft.
IN.TRCDOC' 7
- :- _ : /
- 5..
1
-SPRTAT1ON R01 "I I
fromitheroad and how-cs dtheIXTr tire truck' While the tire truck is ni'maI~kl't in on*
no fl tha
-+c-t..-
fo.:. M ks x-
'this the northeast scto of th
-ilding it is n hitiih s
fa nks locate on thIs tr--- +i.;ould present a sign n
re h rd to the i-TRAC %vehick n be use o t h"gh nlagh n of theful As nioted above-the Hil-TRAC vehicle will also pass by the firing range-, Th7is-'a-rea is used to store munitions for variou vitiies it the site.ThDeatntornpfail S....
- mmtm IptohllzI¥*v*
~mu*,,-
- .. ;"+44
- ?
(DOT) has classified the munitions storý at this facility as a Class C explosive9 the`--'
lowes clasificaiofr all regulated I'lsvs Thesek muniitions, are' sto'red inside a wood
.. Jiatl 0ftrothro od Wile these munitions would not stalrt
-a fire fire in the area may resl iprjectiles being generated.&'
etysml aie.
"riflne an ha.+ caiber handgun muniflons are sto/ed in this.facility.Ba on information from+ the Wneer Arms Co. (wwwwin_ lCer.cm) the MuMze energy of a
~~223.CAlibe rifle bullet is 1,357 ft. lb.(oI case scenario frmunitions stored at this l
tio W le this energy would be severelyreduced if th.bulle. weredischargd from its casing as a result of afiie he potentalmpact to the 1 l-TRAC v-hicle was
-calculated u-sing the energy noted above to be-conservitiv.
Based on mu_
- e c
f 1 -,357 ft. lbts.it was determine that the projetile would not de-elop enou6gh...
to i-e t
damage ft HI-TRAC vehicle.
Continuing up Reservoir Rd. the HI-TRAC vehicle %ill pI pas r the 500 kv lini for
,--'both Units I and 2. While th nes do t'pose a direct fire, hazr should one ofthe
_MT ADOC'.
+
+
- m
+,
+
+
+
4
+
.+
+
+
7;,
+"
+-
+'+
-+
+,
+:'
+ +'
4 4,:+4.+
+> :
- t> 4
- -+,-
EVA!.UA1)O (Of 1111, Il1-T4 ACR SPOR-ATION ROIIE' lanIs fail, and fall on the Ili-TRAC (chici.t IlCl X*k Ox n th,%ihic nehKi ma. ignite. As, noted in Section 8.2.5 of the In n
St 1 lili,,* S vfety Anals-s Re "thr the storage ask the transfer cask uwidro any strwtural degradation frama fre' resultin"g from a' Hl-HT..
fuel tank rflh.e hazr r
9n the route from the Auxiliary Buildin PtotepopoedSSIail.
HFit 14 ser~~S~~t Approxmatey ZG f fnortheast of the ISFSI site is th e maintenance sh o fto perfbrm maintenance on the.fleet or PG&E vechicles used in and arotind the plant.Aside from fte normal lubricants and solvents the largest hazard to the ISFSI fiiyll fomh--d e
ltruck stored at the facility. -As noted earlier ther "are I t~ such fuel trucks located on the site, one '.normally' at the6 mainteniance shp aiid
-one located inside or just outside t protected area. As noted in calculation M-1046, a "distance of 180 ft is required to ensure an exlosonof the fuel truck will not impact one of the Hi-STORM casks at theiSFSl site. -Sincethe distance beten the fuel truck aiAd the ISFS! site, aits closest distanceis less than this distance the movement of this fuel "truck has been cyaluated using a probability rsk assement ap
. As outlined in this asseýssmnt (calc PRAOI-01be)auseof ited amunt oftmes this fuel truck will less than I0o and the frequency of shipments in this area it was determined tht the fuel truck wuld not pose a fire hazard to ie: HI-TRkAC or I-I facility.
tu.TRAC VOC 9
A>
x -
0 1
g EVAIAA!
N) t1a o.o1 lllkIWRAC "In tion t. t onnCn&E fcl truck a 4.t)QI' Al, S.
tank.
frm-an oty t MIplct prrcl psss the ISUSI stc lo%%-ccr. even uith the proposed relocation fthe-road around the norh side of the"Raw ater CR.eervir th" minimum dist-nce
-needed t-o ensure the ~iSFS siwwoulId ntbie damagzed cannot be pro~vided. As such.
admnitrtiv pcic~dre %ill be implemenited toesr the 400 gallon gas tanker does".
not trivel up Resror Rd.' (A6524S79)'
A.ternate Transfer Route p.ox-_mately 9t f*ro6mf tsuth gateof the RCA is the startof the alternate routefr -fo
-theHI.. --
T CvhWicle. This route will proceed up the hill toward the DCPP Main Warehouse (Building 115).- Jus pior to reching the Main Warehouse the Hl-TRAC tranportvehicle will be exposed to the Hazardous Buildin ilding 127) and
" sorage racks for flammable compre I s cyinders. The Haiardous Stotage Blg pp ntfm the-roadway. This buildin-was designed for the
"-storageof hazardous materials and is supplied with an in-rack and building wide su on system on the distanc this buildin s rdn the roadway the inherent safety-feature of the building this building should not pose a threat to the ve also-*' ed to store ammabl Mmressed
'..I -T R A i i '.'
A T 6 i ~ ~
hi.O t s+-
gas cylinders. Since this area is outside the exclusion zone noted in DCM T4O any
_A numberiof flammable gas 4ylinders could be stored in the area. Based on result" documented in Calculation M-1047. it w-as determined that a significant number of A
7A DOC 10
EVAI. - 11O oi: ili llIR 1RAsPORTA1OI.1 Coinprec.cd -gas ltdiries could be,I4ime in thi~. aci~ihu mpacig lc l-TA
%Chick.
t Continuing along the lent rofte theý Il-TRAC transprt vechicke will pass %%i hn 10 ft ofth DPP Ma-in Warchouse (building 1 15). -This building ha an area %%ide rire ieteNtion sion system installed in' the building. In additiOn1, the exterior ls of the buildn r osrce of nona-flammable material. Thisarawddectoan supesin oped wVitth nonflamawible iexterior wills would povideC amptle timeý for
- thell1.RAývhile, to passy this area should a fire occuirwrhile the vehicle is in front of t.
ase onthefir prtecio systrms and the non-combustible rating of the eixteOrio wýalls the DCPP Main'Wrhos houses 'will not pose a ftre, hazarti to the HI-TRAC' Aftr assngbythe DCpp Main Warehous the HI-TRAC vehicle will pass wvithin 15 ft ofteGas C~ylinder Storg facility. This facility is constructed with reiniforcedconciete blocks aprximaitely 7 ft high. This faci~litysol rvd dqaepoeto o h HI-TRACvehicle.
I The-HI-TRAC vehicle will then pass through parking lot S. This parking lot is normially, only used during refueling 'Outages and as such. no vehicles were in the parkingý lot during, our frprtcion walk down. Should fuel movement. occur during tiewencsar pred in this area the samne prowailistic risk Iassessment performed for parking lot H -ThAC-Do
Sk)RIA 0\\
"]I ch ould bc acccptalýFf6i this arta. Afler ng thrw9h iQýi-ing-1,,,%(
9 the I 11-TRAC, o 'hej7jjjýg ra4-c tWiding Rd-ad)wmt t
114L ww
ýýWwa"illenteronto cScrme the r6utc to the ISFSI site conunuc up Dated' 03/06A)l Tus was veligied David 10 c,ýajjjitio'n was reviiwed by:
-7S&VC B4kker s
ý,K
-'A k 12-A
DIAkBLO ICAE K)rm MM 1
Htt~ )R
(.P II~CI fYRSK EVAIl.UAT1 The risk-W the' transporte~r from-explosons admsie rmtesaimybl ydonfaidlity are ro
'osd~drisk skignificant. However, to fiwarenrett these risks ame rnaitied as low as possihk. no hydrogen filling %ill be preformedwhl
'the ranpocr isi h eea raof t11e fhcility., Beyond thisý there will be an ecsinzone maintained around the. op~en ndothvalswreno dicCS will be
~~~ n all vehicle movement wil oe'lirnitodin the area while the transporter is present There is a bulk hydrogen storage-facility at DCPP located east of the Auxiliary Building.
This storage facility houses six tanks which-are 5 icubic fetecf-a total volume capailit cr36 cuic eet. The tanks w
-ebuilt to ASME Code Section VII,Code CaQsel 1203. The-vessel maeali AShIM _A-37 class IV. Akt their normal fil Pressure ofaproimnately 2200 psteod atotal o f approximately,42,000 scf. -Thes tanks are reflld asd ots~hh'r~gs'b~ittwice a month:heitak are held ina 7Msmically~evalxuated-rack,~ wichi eccs in a seismcally evaluated vauIlt -The al backs up against the hill and is only open o'n the side toward the Auxiliairy Building.Th valtispovided with a twelve-.inch ventt in its ruoo to ensure no possil; ul po a e-~r 3eakge.~
The Waks are situated in the vault in two levels -of three taniks. Their supply and process
'piingis octedon heopen sid -of the vault, whic ensures maximuvetn capability shouild thcri be any lcakiL The tanks providedi are fitited with o ve'r pressurizatio poetoanalof the relief valves on the process pipminarevented to a loctio aoveth valt ndaboe ny gntio source fro6m a fill tanker. In addition, the hydrogeni system has jutom~atic excess flow shuioff valves, which are designed to shut off hydrognfopfdmn xed 50
-fn.Normal operation of this facility has onlyone tank online' at a timie siupplying hydrogn The others are shutoff until they are re'quired.
In ron ofth open side of the vault are truck barries whichi kceep any -vehicles fro htigtevialvesand process piping on the tinks. Within the vault and the area' immediately around the opensid ofth vault, ther are no ignition sucs There arenot A lot of industrial standridsfor stationary hydrog en facii~ies. The most widely uegida isfo FASA SaiadfrGsous Hydrogen Systems ka XConsumir Sites", 1999 edition., The DCPP installation meets all the gudance of NFPA 50OA, including distance to other facilities and buildings. The hydrogen is avery light gas and disperses qciypwrwhic reduces any potential for build UP. ;The configu~ration of the vault and the ventinig provided, eliminate any probability for abuild
--up of gas in the vault alrea from a slow leak. Asa aresult; only a, large rupture could, wihnavault, which protects them onalbtoeside. The bulk gas industry operatting wihi i o
al-uton
r'DIABU)
CAV~YIW O.TA flANTý e-xpcc indicates itialiths typeofan swi.rttac
, possibilav "of atank rupture.
ased on the deipýn-4, of the inks and tb~ifaci litN. thec ni crediblceauses- 'of a lare release fitonn the tanki wo~uld be c:hcr a'n ac-cidnt dunniz fiffin$
-rf chicle was allowed to strikth process piping.
This facility is built -to' meet the NFPA 30A g uidaice aix! is miainitained by plant and
- delivery procedures, and mainitenance programs.,[ Theri is, otn anenneporn
-cio at DCPP iat periodically verifies excess flo~w ValC ffuricin"etnk ul
-.to ASMIE Code Section VIII, which doies not require a p~eriodic hydro testing of the tanks.
-As their niornial practice the induistry'rained delivery operators monitor: the tanks and system condtions: prior to and post filling operations. :hedliryoraors are specifically trained 'in detecting degradahinai ilro provid servictoayfiiy
~that ii potent~ially degradad Asanoral jrcdetofligthdlivery operators wil check the fill system adtnvlves using aeak delection spray.
'fany degaaini identified they report it to DCPP. operators flo'r d'isiposition and repair.
.DCPP peronnel do not fill the hydrogen facility and! there are no specific DCPP fill
'Mrr~eures for thataction. These tanks are only filledby industry trained delivety'-.
operators ThMey use their procedures and proess hc are bae n betpatces in he bulk gsindustry.-Prior to6 connecting to 'the fill systemn the delivery operatoii access-_
-the fail~ity-and verifi-the condition of the equipment.-uigtefiln rcs a tner truck is located withini approximately 15 feet of the fclity anid connets to fl connectiorn provided on the pro'ceiss piping.. Thtnkire filled one at a time-anid as each'
-onie is filled it-is secured and the next one is opened. Thbe tiinker uses its supply hose, which reduce the'amount: of hydrogen that is vented in the disconnfecting process.
Durng ie illng rocssstandard, industry saety equipment is ue ntetne n iafety pract~ices are followed for the fill prcs.Once the tanker is disconniected the
- aclity iobevlfor aydegradation and the tanker is removed from die area.
All of the relieveivalves on the system have beeni piped to a central vent above the vault
'which keeps ainekaeaayfo any potential ignition source on the tanker Past oprtn xpeine=
has shown that there have been some instances of what'are called
- ~ops.
hese are the result of a reflief valve lifting during the fill' prcess. Thbepo occurs at the point where the hydrogen mixes with the air and ignites.,Piping the relief
' valves above the vault ensures that these pops occur away fr-om'n th eitanks, are controlled anid quickly extinguished., No other ignitions; or firi~s have occurred at -the -DCPP facility' since its installation.
Based onr the safety. ratces followed and the useofindustry trained deliveiy operators the potential for a tank explosion at,this facility is ve ry low.
'To ensure that there is 'no -vehicle,damage the tanks and their proc e-ss piping are protect -ed from vehicle traffic by vertical pipe barriers. These barriers do not allow any vehicle to come in conta~ct with die tanks or the process pipin an maintain all potential "vehicle iginition so urces -at, a, iifedistancet.
2
'---9
-DtABL CANZYONKPOWER PI ANF BULK HY*ROGEN FACLUrY RLSi EVAL.U N_
in addition to the NFPA'50A guidance, there is oh.cr guidance that is used in the nu"lear indus for dietermnation of the affects of hazards. Rcuiatory(3*&ide 1.91.
l EvIuation of Eiplosions Postulaitýd to Oýcur on Transportation Routes Near.'uclear Poier Plant.
Sits',. deals vith hazards on transoration routes close 1o a power plant.rThis guidance
""povides fo -the movement of hazards and does not really aidress a staiionary ficility W d the hazards of thafacility. he intent of this guidance is to determine h ther -is an unacceptable ind provides several options or methodologies for making that detefronion.,RG 1.91 provides guidance ondetermining probability based-on.,
freijuency of shipment, and distance to transporton routert R 1.91 h aso been used in siti]ngof facilitis at power plants becau of its veryconsrervative appropach R.G-1.91 d
-ioesoiusconsider the amoiiii of gas, but also the risk ofan ignitionfi This R
.9 doe no jus conide thl 1* nta it
.. *:]"...
</:7 risk, --'bais ed oi the frequenty ofa condition ha could result in that ignition. -On ci "1,
71 t-a ispoijation route that risk is based ofithe number of occasions when the ignition sources i
s in a locýai6n, the probaility of theihazad being in acondition to ignitr-ai-d th distac from the plaint In the case of a sationary facility the disstance is fixed and the' f.equency of theignition condition is the only varible.
Alhog RG4-l.91 addresses tra isporting hazardsmand niot stationarY-facilities, the intent_
of the guidic should be applicable to stationary facilities.-To show acceptability the risk must iot be significant. Since the DCPP facility is properly des gned and vented,'
there is little probability of a slow build upof gas from a small leak. In addition, the
, 7-4 tanks are built inerently safe withl protection against over pressurization, excessive'flow, land vehicle amge As a'result, the potential for a large unconitrolled rupture of the tank or the proces piping is not considered credible.
L
-he only otha potential accident where there could be an explosion is durinig the filling
'operatOn. Considering the frequency of the filling (twice a month), safety process used, "industry trained delivery operators, and the operating experience at DCPP and other
. -- `inistria1 facilities, the probability bf this scenario is not considered credible'.' Asa result, tihe risk" frin this stationary facility location is acceptably low even under the guidance Of 1G.9 1.
"in the case oof the potential effect on e
er, the transporter I only be in the "are of the tanks for very' short periods of time as it is entering nd leaving the fuel, "
building.' A Cask Transporter Evaluation Progrnm will be developed, which will Include a requeiremen for an -valuation of potential fire and explosion hazards be perflormed prior" to any wrisport&e movemenit. lThis program will require allefillingoft hydroge.-tanks z,
during t movement to be suspended and all movement of vehicles will be,'."
"administratively controlled to furtherreduci any potential., Because of the non-iredible possibility of an explosion and the limited exposure of the transporter'to this possibility the risk provided by this facility is considered acceptable.
en.3
"DiAND CAN Y(Y'ý; f'43AT R PIANT IM
-9 BULK RYI)PrXiEN FAC RIS In 3ddition, them has bei:6 aý "Uation C64kio an tt;ý7rýotavtw jm Occtsof num diated f Obe tank-s (bvoý # 00-1645.-034397. aM RWS is shový th3t the 66W polentizlis if a vehick ii the ý-al%
ýT of that cv&b=tibn I I
-`ýý_'
banicts punided limii that'06sýsibifitv. therefore tisk-isextrmwav W.
Tbe truck
-Fbir 'almg,ýith the lirhited 'mncýznt of iiýnc that a trang-orter is in the-mri. icsuhs in in' CXtrimficly low probabi
ýý Ic'nsk-.'
lity ilr,4 an Ri ASMECO& section VFII,ýCode Caw 1203 ASTM A-372XIM TV J
NFpA:-5bAa as fbi G&seous. Hydr6j*6 Systems it Conamner Sitce% 1999 edition 1.91, Eýalýiiionlof Explosions Nstulated to 6ccur'on car poi-ir Plaýt Sitein 02105/01,betwcmJeiTLuiiofBOCGases'wýd M4 Spaulding on Fill
,Opimtw 7ýaining
-Dated. 03/OMII s 6yal4ation UgI S uld' 7WS i:ýiifionwas b-Datc4-3 vs t
ThLUCOM Dal:c 02, '5 01 From: Dougasi -"auding Toý. jjff Lutz of WCG&aMe rume I1:30am' Subjct:
III operator aramun 1-1 Jeff told ane th~a all fill operaors for but~p a ie r trained praior to alowing c
thm opwmafilli
~operation-They also do local wpay lea tetngo heimdiasteailtypi o to roeeing with die fill operation. BOC wilt "notfll tam" Unless they-have cunent yrtaitetnceifaio.-Hwvr the d no d te tstng ndhae temsen ot.He did not know w'hat the u~tetn ceftifictin dorain' was.W but be thmiight f was five years. Jeff asho said that all the opeastor examine the faaciiy prior to m4~n anmd am-y problems are comuicae with she ownrsm and xi ftherfill*n will take piace until the.
pioblis haebeeni fixed or deftemine to haeV-fetonteoeain PG&E Letter DIL-03-001 Sheet I of I REVISED PRA CALCULATION Probabilistic Risk Assessment, Calculation File No. PRA01-01, Revision 2, Risk Assessment of Dry Cask/Spent Fuel Transportation within the DCPP Owner Controlled Area.
PACIFIC GAS & ELECTRIC COMPANY PROBABILISTIC RISK ASSESSMENT CALCULATION FILE NO. PRAOI-01 Revision 2
SUBJECT:
Risk Assessment of Dry Cask/Spent Fuel Transportation within the DCPP Owner Controlled Area PREPARED BY:
VERIFIED BY:
a,44'-2
.W.
o ng DATE:,
DATE:
2FNe3 VERIFIED IN ACCORDANCE WITH: CF3.1D15
/
APPROVED BY:
A. Afzali This file contains:
10 pages DATE:
1 /.2 I/Z
- o3
CALCULATION FILE PRA01-01 Rev. 2 RECORD OF REVISIONS REV. 0 Original Calculation.
REV. 1 In this revision, the risk of damage to dry casks due to explosion of an acetylene carrying truck is added to the analysis of risk of damage due to other hazards. This is done to support response to RAI 15-12.
REV. 2 In this revision, the date of the final HI-TRAC evaluation was changed to reflect the actual issuance date (March 6, 2001). The February 2001 date was a preliminary draft, which was the version available at the time this PRA calculation was initially issued (Revision 0 dated February 28, 2001).
INTRODUCTION A risk evaluation was performed to assess the risks of an explosion causing damage to the dry casks while being transported, or while the casks are stored at the Independent Spent Fuel Storage Installation (ISFSI). Specifically, four explosion sources were identified for risk evaluation:
- 1. An explosion of an automobile while the HI-TRAC transporter is passing on the road by Lot 6 or Lot 8 (Lot 8 only of concern if the Lot is occupied with cars)
- 2. A hydrogen explosion in the protected area from the hydrogen tanks while the HI TRAC transporter is in the vicinity.
- 3. An explosion of a 2000 gallon fuel truck while it passes within 180 feet of the ISFSI facility.
- 4. An explosion of a Unit 2 transformer while the HI-TRAC transporter is passing on the elevated road inside the Radiologically Controlled Area (RCA).
DISCUSSION One of the requirements in the Diablo Canyon Spent Fuel Storage Installation (ISFSI)
Safety Analysis Report (SAR) is the evaluation of explosions. During the evaluation process, four potential explosion hazards were identified as needing a risk evaluation.
These four explosion hazards are:
- 1. Explosion of an automobile, while the HI-TRAC transfer cask transporter is passing through the parking lots.
- 2. Explosion of the bulk hydrogen storage facility while the cask transporter is in the area.
Sheet 2
CALCULATION FILE PRAOI-01 Rev. 2
- 3. Explosion of one of the 2000 gallon fuel trucks while it is passing within 180 feet of the ISFSI facility.
- 4. Explosion of a Unit 2 transformer while the cask transporter is moving through the RCA.
ACCEPTANCE CRITERIA Regulatory Guide 1.91 (Reference 1) contains guidance on acceptable risk from explosions for nuclear plants. Regulatory Guide 1.91 states "If conservative estimates are used, an exposure rate less than 10 is sufficiently low."
ASSUMPTIONS
- 1. It is estimated that there will be eight shipments per year of the HI-TRAC transfer casks from the spent fuel building to the ISFSI.
- 2. The hydrogen tanks will not be filled, tested or vented while the HI-TRAC transfer cask transporter is in the vicinity of the hydrogen tanks.
- 3. Additional physical barriers will be erected to prevent the transporter from getting too close to the hydrogen tanks.
- 4. The 2000 gallon trucks will be maintained at least 20 feet from the transporter path during spent fuel transport (Reference 2).
- 5. A 2000 gallon truck will pass by the ISFSI facility once per day. (Reference 9)
- 6. The 4000 gallon fuel truck will be not allowed in the owner controlled area during spent fuel transport. (Reference 2)
- 7. Administrative controls will prevent the 4000 gallon truck from passing by the ISFSI facility.
- 8. Physical and administrative controls will be included in the security plan to prevent vehicle movement in the vicinity of the moving cask transporter.
- 9. The cask transporter, while loaded with a HI-TRAC transfer cask, will be in the vicinity of the bulk hydrogen storage facility less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> during each shipment from the spent fuel building to the ISFSI facility.
10.The cask transporter, while loaded with a HI-TRAC transfer cask, will be in the vicinity of the parking lots less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> during each shipment from the spent fuel building to the ISFSI facility.
Sheet 3
CALCULATION FILE PRAOI-01 Rev. 2
- 11. It is assumed that all bottles within the RCA and outside the protected area will be appropriately secured and chained so they are not hazards. A walkdown will occur prior to the transporter beginning its trip from the Spent Fuel Pool Building to the ISFSI to confirm the bottles are appropriately chained.
- 12. It is assumed that walkdowns will occur in the Parking Lots to assure no potential explosive hazards (such as leaking gas tanks) exist.
13.The design pressure for the HI-TRAC transfer cask is 384 psi. The design pressure for the HI-STORM storage casks arel 0 psi. (Reference 12).
14.Additionally, it is assumed that a walkdown will occur outside the protected area prior to movement of the cask transporter, while loaded with a HI-TRAC transfer cask, to evaluate any transient material located along the pathway.
CALCULATIONS Car Explosion Risk Car explosions almost always are the result of a crash or collision, and rarely, if ever occur in parked cars. Car fires for parked cars are also rare, but have occurred. In fact at least one car fire is known to have occurred at Diablo Canyon. During the transportation of the HI-TRAC transfer cask, administrative and physical controls will be in place to prevent cars from moving while the transporter is in the vicinity of the parked cars. Thus, it is extremely unlikely for a car to explode while the transporter is in transit by the parking lots. Nevertheless, a conservative calculation can be performed to determine the frequency per year of a car explosion occurring while the HI-TRAC transfer cask is being transported in the vicinity of the parking lots (Lots 6 or 8).
A search was conducted for industry data concerning the frequency of explosions of parked cars. No industry information was found. Thus, a plant specific estimate was made, using conservative assumptions. In the approximately 30 years since plant construction began, there has never been a car explosion. Recently, there was a car fire in the parking lot, but the fire did not result in an explosion.
Using the 30 years of experience without a car explosion, a conservative estimate of the frequency of car explosions can be made, by assuming one car explosion occurred in 30 years. The frequency can be converted to an hourly frequency as follows:
Car Explosion Frequency Per Hour = 1 explosion/30years
- 1year/8760 hours) =
3.8e-6 explosions/hour As noted above in the Assumptions section, it is estimated that the HI-TRAC transfer cask transporter will make eight trips from the protected area to the ISFSI per year. As stated in the assumptions section, it is estimated that the transporter will move past the Sheet 4
CALCULATION FILE PRA01-01 Rev. 2 parking areas in less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Conservatively, it will be assumed that the transporter will passing through the car parking areas less than 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per year.
It is assumed that the maximum amount of fuel in any car's fuel tank is 50 gallons. If so, using the formula in Calc. No. M-1046, the Separation Distance (above which there is no risk of cask damage from the explosion) can be calculated. Using 50 gallons as the tank capacity, Wtt = 11770.6
- 50/4000 = 147.13 X, the separation distance is defined as X = 4
- Wtnt 1/
Zg = 1 for a pressure shock of 384 psi (Reference 11) so X = 1
- 147.131/3 = 5.3 feet.
(Note: The same equation applied to a 2,000 gallon fuel truck yields an answer of 18 feet, which is noted in the assumptions and rounded to 20 feet.)
Thus, if the exploding car is within a radius of 5.3 feet of the transporter, the cask could potentially be damaged, according to the conservative calculation. Even if a car explodes while the transporter is moving by the parking lot, it is unlikely that the transporter would be within 5.3 feet of the exploding car. Given that the parking lots are over 1000 feet long and 200 feet wide, it is estimated that the conditional probability of the transporter being within 5.3 feet of the exploding car during the time the transporter passes through the parking lot is less than 1 in 100, or 0.01 (geometry factor). In other words, it is estimated that there is less than a 1 in 100 chance that an exploding car will be within 5.3 feet of the transporter at the time of the explosion.
Thus the conservative annual probability of a car explosion occurring that damages the cask on the transporter is:
Annual probability of cask damage due to car explosion = 3.8e-6 car explosions/hour
- 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> /year
- 0.01 = 3.8e-7.
According to Regulatory Guide 1.91 Revision 0, if conservative calculations are used, an exposure rate, of less than le-6/year is acceptable.
Hydrogen Tank Explosion The bulk hydrogen facility contains 6 hydrogen tanks. The hydrogen tanks and hydrogen piping contain relief valves, which are vented to atmosphere. Because of the design, a hydrogen explosion is considered almost incredible. However, hydrogen fires are credible, and appear in the EPRI Fire Events Database (Reference 5), including fires caused by a stuck open or leaking relief valve.
Sheet 5
CALCULATION FILE PRA0I-01 Rev. 2 The EPRI Fire Events Database gives an annual frequency of Hydrogen fires of 3.2e 3/year (Reference 5). It is conservatively assumed the entire frequency of fires can be assigned to the bulk tank facility. Thus, the hourly frequency of hydrogen fires at the bulk tank facility is:
Hydrogen Fire Frequency = 3.2e-3/yr
- yr/8760 hrs = 3.7e-7/hr Because of the design of the hydrogen system, which does not allow hydrogen to accumulate in confined spaces, there is an extremely low probability of a hydrogen explosion, even if a hydrogen fire occurs. If we conservatively assume a conditional probability of 0.1 that a hydrogen explosion occurs, given a hydrogen fire has occurred, then the Hydrogen Explosion Frequency is:
Hydrogen Explosion Frequency = 3.7e-7/hr
- 0.1 = 3.7e-8/hr The hydrogen explosion is a concern when the HI-TRAC transfer cask transporter is in the vicinity of the hydrogen tanks. As noted in the assumptions section, the transporter should be in the vicinity of the hydrogen tanks less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> for each shipment, with eight shipments per year. It will be assumed that the transporter will be in the vicinity of the hydrogen tanks a total of 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per year.
On a yearly basis, the probability (exposure rate) of a hydrogen explosion potentially damaging the HI-TRAC cask is:
3.7e-8/hr
- 10 hr/yr = 3.7e-7/yr According to Regulatory Guide 1.91, "if conservative estimates are used, an exposure rate less than 10-6 per year is sufficiently low."
2000 Gallon Truck Explosion There is data available from the Department of Transportation on truck crashes and truck fires. The 1996 NHTSA statistics (Reference 6) show a "Large trucks involvement rate" of 216 per 100 million miles." Table 38 of the 1996 Motor Vehicle Crash Data (Reference 7) shows that 0.3 percent of large truck crashes result in fires. Thus, the frequency of truck fires is 216/(100*108)
- 0.003 = 6.5e-9/mile. For the purposes of this analysis, it is conservatively assumed that all truck fires result in an explosion. Thus, the explosion rate for truck fires is 6.5e-9/mile.
Regulatory Guide 1.91 provides the following equation for use in the evaluation of explosions:
r = nfs, where n= explosion rate for the substance and transportation mode in question in explosions per mile Sheet 6
CALCULATION FILE PRA0I-01 Rev. 2 f = frequency of shipment for the substance in question in shipments per year, and s = exposure distance in miles It is assumed that the ISFSI exposure distance, s is approximately 1000 feet.
As noted above in the assumptions section, the frequency of shipments is 1 per day, or 365 per year.
Thus, r = 6.5e-9/mile
- 365
- 1000/5280 = 4.5e-7/year According to Regulatory Guide 1.91 Revision 0, if conservative calculations are used, an exposure rate, of less than le-6/year is acceptable.
Transformer Explosion There are 6 active, normally energized transformers located on the Unit 2 side (south side) of containment. Three are single phase 500kV transformers, two are three phase 25kV transformers and the last is a three phase 12kV transformer. There are also two spare transformers stored adjacent to the active transformers. The transformers are located at elevation 85'. The road for the transporter is at elevation 115' and runs perpendicular to the potential explosion zone for under 600 feet. There is a sloped, rock covered embankment located approximately 120 feet from the transformers. That embankment is 30 feet tall and would take the brunt of the explosions force heading that direction. On the top of the embankment at elevation 115' is a paved lot that is used as a storage area - this has already been evaluated in reference 4.
Approximately 60 feet away from the ledge of the embankment is the road that the HI TRAC transporter will traverse.
The layout of the transformers is such that the three single phase 500kV transformers are located closer to the pathway, while the two three phase 25kV transformers are mostly shielded from the pathway by the 500kV transformers. The 12kV transformer is located further yet, and is also shielded by the other transformers. All of the active transformers have a fire suppression system surrounding them which will activate after a fire.
Failure rate for transformers was obtained from a standard nuclear industry source (Reference 10) using catastrophic failures, which are composed of open and short circuits plus removal by protective features; i.e. potential explosive failures. The recommended values from the reference were utilized, which is conservative for the new 500kV transformers installed on Unit 2.
Transformer type Failure Rate Reference 500 kV Single Phase 2.6E-7 failures per hour Page 369, Section 6.3.1.6 Transmission 12kV-25kV Three Phase 6.6E-7 failures per hour Page 371, Section 6.3.2.1 Transmission I
I Sheet 7
CALCULATION FILE PRAOI-01 Rev. 2 Consistent with the assumptions throughout this calculation, the conservative time of 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of transport will be used. There are three transformers of each type.
Additionally, there is a geometric factor to consider, for an explosion would have to impact the transporter traveling approximately 240 feet away at an elevated height of 30 feet above the transformer. The geometric factors utilized assumed that there would be no bounce, or reflection off structures or the rock embankment that could impact the transporter and that the blast was evenly distributed over the potential 180 degrees of blast direction. As noted earlier, the transporter will be approximately 240 feet away from the transformers and elevated approximately 30 feet. As a result, the ratio of the transformer target area to the total blast area is quite small, and is judged to result in geometry factors of 5E-3 for the 500 kV transformers and 1 E-3 for the 12-25kV transformers, assuming a 20% throughput of energy past the 500kV transformer acting as a directional shield.
Thus: 500kV: (2.6E-7 failures per hour per transformer) x (3 transformers) x (10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per year) x ( 5E-3 geometric) = 3.9E-8 per year And 12-25kV:
(6.6E-7 failures per hour per transformer) x (3 transformers) x (10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per year) x (1 E-3 geometric) = 1.98E-8 The total risk is the sum of the risks from the two calculations for the 6 transformers, which is 5.9E-8 per year.
The risk from a transformer explosion, based on exposure time and distance, is estimated to be less than the 1E -6 acceptance criteria stated by Reg. Guide 1.91.
Acetylene Truck Explosion The risk of damage from this hazard is judged to be bounded by the risk of damage due to 2000 Gallon Truck Explosion. That is, using Regulatory Guide 1.91 approach for evaluating the risk of damage due to explosion of an Acetylene Truck, the estimates of parameters used for calculating exposure rate (r) are bounded by the estimates used for the 2000 Gallon Truck Explosion on the basis that:
n (explosion rate) is the same since the primary reason for the Acetylene tank explosion is judged to be due to large truck crashes. Note that under the Hydrogen Tank Explosion, the explosion rate is calculated as 3.7E-8 per year.
f (frequency of Acetylene shipment) is judged to be less than the frequency of 2000 Gallon Truck shipment.
Sheet 8
CALCULATION FILE PRAOI-01 Rev. 2 s (exposure distance in miles) is judged to be less than that of the 2000 Gallon Truck hazard due to lower potential energy release from explosion of a few Acetylene tanks than the potential energy release from explosion of 2000 gallon of oil.
As an alternative, the risk of damage due to Acetylene Truck Explosion can be estimated in a similar manner to the risk of damage due to Hydrogen Tank Explosion.
Again, it is judged that the risk is bounded by the risk of damage due to Hydrogen Tank Explosion and is less than 1.OE-6 per year.
Therefore, it is judged that, based on Regulatory Guide 1.91 criteria, the risk of damage due to Acetylene Truck Explosion is less than 1.0E-6 and is low enough to be considered insignificant.
Note that the risk of damage is a conservative measure to use as a surrogate for the risk to the public on the basis that the damage to the casks does not constitute cask barrier integrity or the fuel cladding integrity failure.
RESULTS The risks associated with explosions which could damage the HI-TRAC transfer cask or the HI-STORM storage cask were evaluated. All the hazards evaluated resulted in conservative estimates for exposure rates of less than 106, which is risk insignificant.
According to Regulatory Guide 1.91, this risk level is acceptable.
RECOMMENDATIONS Each of the assumptions listed in the assumptions section of this calculation should be implemented through administrative procedures. This is being tracked by AR A0524878.
REFERENCES
- 1. "Regulatory Guide 1.91, "Evaluation of Explosions Postulated to Occur On Transportation Routes Near Nuclear Power Plants," February 1978.
- 2. PG&E Calculation M-1 046, Revision 0, "Minimum Separation Between Fuel Tanks and Storage Casks."
- 4. "Evaluation of the HI-TRAC Transportation Route", Dave Hampshire, dated March 6, 2001.
- 5. EPRI, "Fire Events Database for U.S. Nuclear Power Plants."
Sheet 9
CALCULATION FILE PRAOI-01 Rev. 2
- 6. US Department of Transportation, "Federal Motor Carrier Safety Administration Fact Sheet 1998." http://www.fmcsa.dot.gov/factsfigs/mchsstats/98factsheet.htm.
- 7. US Department of Transportation, "Traffic Safety Facts 1996." http: //www nass. nhtsa. dot. gov/nass/, NASS GES Annual Reports (1996).
- 8. PG&E Calculation M-1047, Revision 0, "Minimum Separation Between Acetylene Tanks and Transfer Casks."
- 9. "Telecon with Lou Ricks on Fuel Truck Frequency," Dave Hampshire and Lou Ricks, 2/13/01.
- 10. IEEE Std. 500-1984, "IEEE Guide to the Collection and Presentation of Electrical, Electronic, Sensing Component, and Mechanical Equipment Reliability Data for Nuclear-Power Generating Stations."
11.Army TM 5-1300 - Structures to Resist the Effects of Accidental Explosions, November, 1990, page 2-57.
- 12. Holtec Calculation HI-2002512 Rev. 1; February 14, 2001 Sheet 10