ML20035D176
| ML20035D176 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 04/08/1993 |
| From: | Steven Bloom Office of Nuclear Reactor Regulation |
| To: | Tira Patterson OMAHA PUBLIC POWER DISTRICT |
| References | |
| TAC-M85116, NUDOCS 9304120220 | |
| Download: ML20035D176 (7) | |
Text
._
Docket No. 50-285 April 8, 1993 I
Hr. Terry L. Patterson Division Manager - Nuclear Operation Omaha Public Power District 444 South 16th Street Mall Mail Ftop 8E/EP 4 Omab, Nebraska 68102-2247 l
Dear Mr. Patterson:
f
SUBJECT:
SPENT FUEL POOL RERACK - FORT CALHOUN STATION (TAC N0. M85116)
By letter dated December 7, 1992, you proposed revisions to amend Specifications 2.8, 3.2 (Table 3-5), 4.4.2, 5.10.3, and Figure 2-10 of your l
Technical Specifications.
These changes will allow an increase in the number of spent fuel assemblies which may be stored in the Spent Fuel Pool upon
{
modification to the Spent Fuel Pool stwage racks. To continue our review we i
need additional information from you. The enclosed request for additional information (RAI) was discussed by the NRC staff and your staff on April 6, i
1993. As discussed during the telecon, we anticipate your responses to our request for additional information to be submitted within four weeks.
If you have any questions about this mattcr, please do not hesitate to call me at 301-504-1313. This requirement affects fewer than 10 respondents and, 4
therefore, is not subject to Office of Management and Budget review under j
Public Law 96-511.
l Sincerely, ORIGINAL SIGNED BY:
Steven D. Bloom, Project Manager Project Directorate IV-1 i
Division of Reactor Projects - III/IV/V Office of Nuclear Reactor Regulation
Enclosure:
RAI cc w/ enclosure:
l See next page DISTRIBUTION:
Docket File OGC l
NRC & LPDRs ACRS (10)
PDIV-1 r/f ABeach, RIV l
i JRoe MVirgilio GHubbard PNoonan SBloom i
OFC LA/PD4-l M.
PM/PD4-1 D/PD4-1/2[
,e NAME PNoonan
$ Bloom /vw GHubbard DATE M/7/93 k/ 7/93
- /(/93
~
OfflCIAL RLCORD COPY Document Name: FC851168.RAI
/U{
l !
I 9304120220 930408 o
l PDR ADDCK 05000285 P
a af og i
[$ikI[4 UNITED STATES
]
NUCLEAR REGULATORY COMMISSION WASWNGToN, D.C. 20555 @ 01
- =***
April 8, 1993 Docket No. 50-285 Mr. Terry L. Patterson Division Manager - Nuclear Operation Omaha Public Power District 444 South 16th Street Hall Mail Stop 8E/EP 4 Omaha, Nebraska 68102-2247
Dear Mr. Patterson:
SUBJECT:
SPENT FUEL POOL RERACK - FORT CALHOUN STATION (TAC NO. M85116}
i By letter dated December 7, 1992, you proposed revisions to amend Specifications 2.8, 3.2 (Table 3-5), 4.4.2, 5.10.3, and Figure 2-10 of your Technical Specifications. These changes will allow an increase in the number of spent fuel assemblies which may be stored in the Spent Fuel Pool upon modification to the Spent Fuel Pool storage racks. To continue our review we need additional information from you. The enclosed request for additional information (RAI) was discussed by the NRC staff and your staff on April 6, 1993. As discussed during the telecon, we anticipate your responses to our request for additional information to be submitted within four weeks.
If you have any questions about this mattei, please do not hesitate to call me at 301-504-1313. This requirement affects fewer than 10 respondents and, therefore, is not subject to Office of Management and Budget review under Public Law 95-511.
Sincerely, G
- ]
,yGo J, Ue=
j Steven D. Bloom, Project Manager i
Project Directorate IV-1 Division of Reactor Projects - III/IV/V Office of Nuclear Reactor P.agulation
Enclosure:
RAI cc w/ enclosure:
See next page l
Mr. Terry L. Patterson l
Omaha Public Power District Fort Calhoun Station, Unit No, I cc:
i Harry H. Voigt, Esg.
i LeBoeuf, Lamb, Leiby & MacRae 1875 Connecticut Avenue, NW Washington, D.C.
20009-5728 Mr. Jack Jensen, Chairman Washington County Board l
of Supervisors Blair, Nebraska 68008 Mr. Raymond P. Mullikin, Resident Inspector U.S. Nuclear Regulatory Commission Post Office Box 309 fort Calhoun, Nebraska 68023 Mr. Charles B. Brinkman, Manager Washington Nuclear Operations Combustion Engineering, Inc.
12300 Twinbrook Parkway, Suite 330 Rockville, MD 20852
?
Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 l
Harold Borchert, Director Division of Radiological Health Nebraska Cepartment of Health
-1 301 Centennial Mall, South Post Office Box 95007 Lincoln, Nebraska 68509 l
Mr. James W. Chase, Manager Fort Calhoun Station Post Office Box 399 Fort Calhoun, Nebraska 68023 1
l i
i
i
?
i
?
Enclosure l
REQUEST FOR ADDITIONAL INFORMATION ON THE I
SPENT FUEL POOL STORAGE RACK APPLICATION AT i
FORT CALHOUN UNIT 1 Please refer to Reference 1 for questions 1 through 13.
1.
The licensee, Omaha Public Power District (OPPD), utilized compression gap elements in the dynamic analyses to provide for opening and closing i
of interfaces such as the pedestal-to-bearing pad interface.
Provide the magnitude of the largest compression force and the location of the gap element and the time when that event occurred for the case of I
RUN I.D.-DRALMHEO.RF8 of the submittal (Reference 1).
2.
Provide the details of the findings of RUN I.D.-DRALMHEO.RF8 for the fuel assembly impacts against the cell wall:
i a) The magnitude of the largest impact force and location of the impact in the fuel assembly and cell wall, b) The masses and accelerations of the fuel assembly and the cell wall at that critical point, c) The effects of the fluid between the fuel assembly and cell wall during the interactions, and i
d)
Provide exoerimental study that varifies the numerical simulation of the fuel asse...bly and wall intccactions.
3.
Provide the largest magnitude of the fluid press'tre distribution along the height of the rack during the fluid and rack interactions for each case of the 3-D single and multi-rac( analyses. Also, provide results of any existing experimental study that verifies the simulation of the fluid coupling utilized in the numerical analyses.
[ Note: OPPD is
~
requested to provide results of experimental study in addition to the experimental study indicated in Reference Section of the submittal. The experimental study mentioned in Reference Section does not reflect realistic rack configuration, boundary conditions, rack and fluid interaction, and dynamic input loading conditions.]
4.
OPPD states that the four sets of artificial time histories were used j
for dynamic analyses.
From the review of the response spectra, it is i
found that not only the response spectra calculated for each individual 1
time history did not envelop the licensing Dasis design response spectra of the final safety analysis report (FSAR), but also the average calculated response spectra generated from these time histories did not envelop the design response spectra of FSAR.
Section 3.7.1 of the standard review plan (SRP) provides a guideline that the average calculated response spectra should envelop the licensing basis design response spectra for use of multiple time histories. OPPD is requested to demonstrate adequacy of the artificial time histories used in the
]
i analyses (e.g., the extent of conformance to a target power spectral j
density (PSD) function of the artificial time histories) or to use new I
artificial multiple time histories such that the average calculated
.e-
. +-
+Am+
response spectra of the time histories should envelop the licensing basis design response spectra, and perform the structural analysis.
5.
OPPD simply states that analyses were performed for checking the integrity of the pool liner. No detailed quantitative information were provided in the submittal. OPPD is requested to provide the following:
a) Analytical approaches or methodologies, b)
Loading conditions, c)
Failure (tear and rupture) criteria, d) Material properties used including concrete bearing strength and friction between the pedestal and liner, and e) Provide complete summary of the findings in a tabular form.
6.
With respect to the fuel pool structure analyses, Table 8.5.3 of Reference I shows the limiting safety margin of 1.03 for a wall. OPPD concluded that the pool structure maintains its structural integrity 3
during a critical loading combination since the safety margin is larger than 1.0.
However, the calculated factor of safety is very marginal, and it could be changed depending on analytical methodologies and other parameters such as material properties used in the analyses.
OPPD is requested to submit the input and output of the pool structural analyses of a slab and five walls for all four different critical loading conditions including physical dimensions and locations of the reinforcement of the pool structure for further staff review.
Any technical assumptions made during the analyses should be discussed in details.
7.
With respect to the analyses of the piles supporting the pool structure, Table 8.5.4 of Reference 1 shows the safety margin of 1.07 for the piles. OPPD states that the pile analysis was done using the finite element analysis program of ANSYS. However, OPPD did not provide any i
technical details and summary results in the submittal.
From the review, it appears that the pile analysis did not take into account effects of the soil-pile-structure interactions during the dynamic loadings of the operating basis earthquake (OBE) and safe shutdown earthquake (SSE).
OPPD is requested to provide complete details of the j
analyses (i.e., loading conditions, soil and pile properties, effects of 1
4 the soils, analysis methodologies, dimensions of pile, and supporting and adjacent structures, etc.) including summary of the results (i.e.,
bending moments, shear and axial forces, deformations, etc. versus their corresponding allowables).
8.
OPPD states that all computer programs utilized in performing the rerack analysis were verified in accordance with Holtec International's nuclear Quality Program (QP).
Indicate whether the QP was reviewed and approved by the NRC staff.
Also, indicate whether or not the QP documentation is available for staff audit.
9.
Describe plan and procedure for the post operating basis earthquake (0BE) inspection of fuel racks gap configurations.
y n
s
}
I t 10.
Discuss the basis for selecting storage locations for newly discharged spent fuels versus the spent fuels which have been stored for some periods (i.e., the fuel storage location plan and the associated load distribution patterns as well as their effect on pool stress distribution and permanent deformations due to the previous spent fuel loadings,etc.).
11.
Discuss the key procedures and assumptions for generation of three dimensional multi-rack model used in the analysis and basis for considering boundino cases for analysis (e.g., are the so-called bounding cases truly bounding?).
12.
Why did OPPD use the range of coefficient of friction of 0.2 to 0.8 ?
Is this still the best range? In addition, OPPD is requested to provide the results of the dynamic analyses similar to the case of RUN I.D.-
DRALMHEO.RF8, but with the coefficients of friction of 0.01 and 0.99, respectively.
Please summarize the two results in tabular forms similar to Table 6.7.3 of Reference 1.
13.
Are the stress ratios provided for rack support assembly and the supporting concrete based on strictly linear assumption of structural behavior? Do these numbers truly reflect reality?
Please refer to Reference 2 for questions 14 through 20.
14.
Describe the factors attributable to the large discrepancy between the whole pool multi-rack (WPMR) analyses of Chin Shan and the plant in New Jersey pertaining to the ratios of the maximum displacements between the WPMR and the single rack analyses.
15.
Given the statement that tracking the inter-rack gap showed that the presence of water has the effect of injecting a certain symmetry into the motion of adjacent racks, leading to a strong in-phase motion of component, try to explain the 60% increase of the maximum displacement of an WPMR analysis over that of a single rack analysis as shown in Table 1 of Reference 2.
16.
Referring to Figure 9 of Reference 2, would the statement that the computed gap amplitude of 0.1 to 0.2 inch, oscillating at approximately 2 Hz frequency, generally apply to most of the racks similar to the one analyzed? Discuss any safety significance attributable to these parameters.
17.
In a WPMR analysis, was a randomly selected friction coefficient (based on the coefficient of friction of 0.5 with standard deviation of 0.125) j at a given instant applied to all racks identically?
If one were to select random fH ction coefficient for each rack at each instance, would the results be appreciably changed?
18.
Was there any physical rack design change necessitated by the res;lts of the WPMR analysis?
If yes, describe the change (s).
. 19.
In the WPMR analyses performed for Chin Shan and the New Jersey plant, discuss how the fluid rack int.araction effects was accounted for as well as the assumptions made in the codification of the computer code used for the analyses.
20.
Discuss the error band associated with the used of central difference equations in the representation of the non-linear governing equation of motion.
Reference:
1.
" Application for Amendment of Operating License," Letter dated December 7,1992 from Omaha Public District to U.S. NRC.
2.
Soler, A. and Singh, K.,
"Some Results From Simultaneous Seismic Simulations of All Racks in A Pool," INNM Spent Fuel Management Seminar X, Washington, D.C., January,1993.
i 5
)
i i
l l
i i
.