ML20206J420
| ML20206J420 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 06/24/1986 |
| From: | Herrick R CALSPAN CORP. |
| To: | |
| Shared Package | |
| ML20206J417 | List: |
| References | |
| OLA, NUDOCS 8606270164 | |
| Download: ML20206J420 (12) | |
Text
AFFIDAVIT OF R. CLYDE HERRICK REGARDING THE INTERVEN0R'S APPLICATION FOR STAY I, R. Clyde Herrick, being duly sworn, state as follows:
1.
I am employed by the Franklin Research Center (FRC), Division of Arvin/Calspan, Philadelphia, Pennsylvania as a Principal Engineer in the Engineering Department.
I serve as a consultant from FRC to the U.S. Nuclear Regulatory Commission (Engineering Branch, Division of PWR-A Licensing, Office ofNuclearResearchRegulation). A copy of my resume is attached.
2.
I have participated in the technical evaluation of the application, by the Pacific Gas and Electric Company, for high density spent fuel storage in the spent fuel pools of Diablo Canyon Units 1 and 2.
My participation was with respect to the structural design aspects of the spent fuel racks and the spent fuel pools.
I am the principal author of Technical Evaluation Report TER-C5506-625, dated April 30, 1986, which is included as Attachment A in the NRC Safety Evaluation Report dated May 30, 1986, supporting the issuance of License Arrendments No. 8 and No. 6 for Diablo Canyon Units 1 and 2, respectively, regarding the expansion of the spent fuel pools.
3.
I have reviewed the Application for Stay by San Luis Obispo Mothers for Peace and the Sierra Club, Santa Lucia Chapter, dated June 16, 1986 and the attached affidavit by Dr. Richard B. Ferguson, dated June 16, 1986.
I have addressed seven issues identified in the Ferguson Affidavit. These seven issues, discussions of which follow, form the basis of Dr. Ferguson's assertion that "the proposed reracking would significantly reduce the margin of safety for the spent fuel storage system and pose a risk to the public health and safety and protection of the environment".
These issues are:
A.
Rack to Wall Interactions B.
Rack to Rack Interactions C.
Multi-Rack Interactions D.
Cushioning Effect of Water E.
Design Differences of Rack "H" F.
Fuel Pool Seismic Displacements G.
Free Standing versus Anchored Racks 4.
Rack to Wall Interactions:
The Issue:
"The Commission has not evaluated the potential for collisions of the racks with the walls of the pool."
References:
Paragraphs 12, 14, 15, 16, 20, and Appendix A
$$0 DO G
Response
In support of the licensing amendment, the analysis model used for dynamic response analysis of the rack modules was valid for the consideration of adjacent rack modules and adjacent pool walls. The development of the analysis model is discussed in Section 3.1.4 of Appendix A to the NRC Safety Evaluation Report, beginning on page 16, and is supplemented by the description provided in the response to Issue B in Paragraph 5 of this Affidavit.
The only item not specfically expressed in the analysis as applied to a pool wall was the local acceleration of the wall during contact with the rack module. Wall motions of concern are those associated with the high acceleration components of the acceleration time-histories. These are higher frequency components in the acceleration time-history that are associated with wall displacements acting in a time period shorter than the response time of the rack. These wall displacements could, therefore, affect the rack as local displacements in addition to the calculated rack displacement at impact.
However, my consideration of the wall displacem a ts associated with these high acceleration components indicate that their magnitude is a fraction of the maximum computed rack displacements. Combining these wall displacements with the computed maximum rack impact displacements did not produce forces on the rack modules in excess of the allowable values.
Dr. Ferguson, in Paragraphs 14,15, and 20 of his Affidavit indicates that, based on his analysis, the rack to rack impact forces and rack to wall impact forces are many times the allowable loads on the rack modules.
Reference to Dr. Ferguson's analysis method, as shown in Appendix A of his Affidavit, indicates that Dr. Ferguson has derived the well known phenomenon that a constant force (or constant acceleration) applied suddenly, and then sustained, on a simple mass-elastic system will result in twice the force (or acceleration) being realized at the mass of the simple system during the course of its dynamic response. However true this might be, Dr. Ferguson's formula can not describe the acceleration and dynamic response of a rack module bearing against a pool wall that is accelerating according to the acceleration time-histories developed for the analysis. His mathematical model is inadequate.
While simple analysis can often serve well to check more complex phenomena, the major inadequacy of Dr. Ferguson's analysis was that he incorrectly assumed the wall to be accelerating at a constant rate, and did not consider the distributed mass and flexibility of the rack moriules.
In using a constant wall acceleration in his analysis, he failed to consider the short time duration of the high wall accelerations in relation to the generally slower response times of the rack modules and fuel. Thus, Dr. Ferguson predicted excessive forces on the racks using analysis that is badly out of context for this application.
Conversely, the analysis reviewed and evaluated in Appendix A of the NRC Safety Evaluation Report correctly addresses the technical requirements, their proper application and context.
It is an adequate analysis.
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5.
Rack to Rack Interactions:
The Issue:
"The Commission has also failed to assess properly the potential for collisions of one rack with another."
References:
Paragraphs 12, 14, 17, 18 and 20
Response
Dr. Ferguson indicated, in Paragraph 17 of his Affidavit, that tha analyses were based upon fallacious assumptions, but he offered no technical st.; port of his statements other than an erroneous analysis of rack-wall impact (see response to paragraph 4).
On the contrary, the Commission approved analyses that carefully simulateo the nonlinear dynamic behavior of the spent fuel rack modules as reviewed and evaluated in pages 16 to 40 of Appendix A to the NRC Safety Evaluation Report.
The analyses were based upon well established engineering principles and included the following modeling considerations:
elastic flexibility and material strength of the rack module o
impacts of the spent fuel assemblies oscillating in clearance o
space within the storage cells of the rack off-center partial fuel loadings as well as full fuel load o
o a documented range of friction coefficients between the mounting pads and the pool liner the hydrodynamic effects of water between the racks and the o
pool wall or an adjacent rack o the effects of impacts with an adjacent rack or the pool wall o the simultaneous consideration of three orthogonal seismic acceleration time-histories (3-dimensional analysis)
The maximum dynamic response was analyzed conservatively by choosing for analysis the rack with the geometrical characteristics that produce high dynamic response. The maximum forces of collisions with an adjacent rack were analyzed by assuming the adjacent rack to be a mirror image of the high-reponse rack under dynamic motion simulation analysis, so that the response of the adjacent rack was equally high and opposite in direction.
This assumption conservatively maximized the computed impact forces between two adjacent rack modules, as opposed to the more realistic case where adjacent dissimilar racks would have lower dynamic response amplitudes and a different response frequency spectrum.
Contrary to Dr. Ferguson's statements, the analysis provided in support of the licensing amendment included a realistic consideration of each physical phenomenon influencing the motion of a fuel rack, and rack-to-rack impact forces were based on the high-response racks. Multi-rack interactions are addressed in Paragraph 6 below..__
6.
Multi-Rack Interactions:
The Issue:
" Third, the Commission has ignored the potential for multi-rack collisions --."
References:
Paragraphs 12, 15, 18, and 20.
Response
Multi-rack collisions were considered and are assumed to occur. The analysis approved by the Comission recognized that the dynamic response motion of the racks is more complex than lateral sliding of each rack unit, and that the maximum inter-rack impact occurs at the top of the rack where the sliding motion of the rack is augmented by angular motion of the rack associated with the mounting feet bouncing off the floor.
Whereas the racks will impact randomly with adjacent racks in a complex pattern of inter-rack impact, the maximum forces on each impacting pair of adjacent racks was analyzed conservatively by considering the maximum forces resulting from the assumption of two adjacent identical, high-response, rack modules undergoing equal and opposite motions as described in the response of paragraph 5.
With the dissimilarity of racks in the pool and the complex response of each rack, the possibility that two or more racks could be positioned tightly together and move in unison to damage another is extremely remote. The bouncing nature of each rack under the higher earthquake accelerations produces lateral movements at the top of racks that will prevent tightly packed group behaviour of the racks under the acceleration levels of concern.
In Paragraph 15 of his Affidavit, Dr. Ferguson states that, " Basic physical principles predict that the forces generated in a collision with two racks sliding would be twice as large as for single racks, three times for three racks, etc..."
Again, Dr. Ferguson seems to be mislead by an overly simplistic approach as discussed in Paragraph 4 above, and appears to be treating the rack modules as rigid bodies under constant,'or long-term, acceleration. Actually, the racks are flexible, mass-elastic bodies subjected to random excitation transmitted mostly by rapidly-changing friction forces between the rack mounting feet and the pool floor. As such, it would be extremely improbable that multiple racks could be bound tightly together to impact with another such group or wall.
Even if this could happen, the forces would not be as predicted by Dr. Ferguson (see paragraph 4 and 5).
In summary, the analyses reviewed, evaluated and approved in Appendix A of the
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Safety Evaluation Report adequately address the considerations of multi-rack impacts.
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7.
Cushioning Effect of Water:
The Issue:
" Fourth, the Commission has over-emphasized the cushioning effect of the Water in collisions involving fuel racks."
References:
Paragraphs 12 and 19.
Response
Dr. Ferguson stated in Paragraphs 12 and 19 of his Affiaavit that the cushioning effect of the water was overemphasized and unreasonably large.
However, he offered no technical basis for his conclusions, and did not provide any reasons why he believed this to be true.
It is important to consider the eff cte of water surrounding and between the rack modules. The virtual mass of t he eater adds to the mass of the rack module in determining the dynamic response
- une rack module to earthquake excitation.
In addition, cushioning is derived from accelerating the mass of water from between adjacent racks that are moving toward each other, or from between a rack and a wall.
It should be noted that these effects constitute hydrodynamic coupling as discussed on page 23 of Appendix A to the NRC Safety Evaluation Report. These effects involve the mass of a frictionless (inviscid) fluid.
This is not fluid damping.
Fluid damping was not included in the analysis.
The hydrodynamic coupling employed in the analysis constitutes state-of-the-art analysis based upon established fluid dynamics principles. The model was reviewed specifically to determine that the coupling was realistic and conservative.
8.
Design Differences of Rack "H":
The Issue:
"Fifth, one rack in particular (fuel rack "H") has a different configuration from the other racks."
References:
Paragraphs 12 and 21.
Response
In Paragraphs 12 and 21 of his Affidavit, Dr. Ferguson expressed concern about the mounting supports of rack "H" being shorter than those for the adjacent rack modules, thus providing the possibility that the protruding bascplates of adjacent racks could damage rack "H" above the baseplate.
PG&E records show that in recognition of this possibility, girdle bars were added to each "H" rack at the level of the baseplates of adjacent racks prior to issuance of the NRC Safety Evaluation Report. Therefore, with the added girdle bars in place, any impacting of rack "H" by the baseplates of adjacent fuel racks will occur on the girdle bars provided for that purpose and not on the storage cell walls.
9.
Fuel Pcol Displacements:
The Issue:
"During the PHE, the spent fuel pools (and indeed the entire power plant) are expected to undergo displacements
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of up to three feet in the north-south direction and eight feet in the east-west direction."
Reference:
Paragraph 13.
Response
In Paragraph 13 of ' M Affidavit, Dr. Ferguson incorrectly assumes that the spent fuel pools, "are expected to undergo displacements of up to three feet in the north-south direction and eight feet in the east-west direction". He appears to have based his assumption on plots cT displacement that he prepared from double integration of the time-history data to yield displacement without realizing the possible errors that may result.
Two sources of error are explained in the following paragraphs.
The first and major source of error is expected to result from a slight offset, or bias, acceleration value in the acceleration time-history data.
The acceleration time history was generated from the specified earthquake spectrum by a modified version of the computer program SIMQKE, a well accepted and widely used method. Procedures in the use of the program require that a baseline correction be made to adjust the mean square of velocity, and to scale the peak accelerations predicted.
In the course of performing these procedures, it is possible that a very small offset acceleration was introduced to the time-history data which, upon double integration to yield displacement, led to the very large earthquake displacement cited by Dr. Ferguson.
A second, and possibly smaller, source of error may have resulted from Dr.
Ferguson's integration methods. Because the acceleration time-histories were defined as sets of acceleration values at incremental points in time, Dr. Ferguson would probably have used a double summation procedure instead of a true mathematical integration of the acceleration data set. The amount of error that would accumulate from a summation procedure depends upon the smootning, or interpolation procedures that are used. The greatest error would be realized from direct double summation of the time-history data set without the use of a smoothing, or interpolation procedure.
However, these errors leading to the large displacement plotted by Dr. Ferguson did not adversely affect the licensing analysis. The purpose of the acceleration time-history was to input the earthquake excitation to the dynamic analysis, which used excitation in the form of acceleration to produce forces on the rack module. The analysis was not significantly affected by slight differences in offset acceleration.
In confirmation of the above, an inspection of the di.splacement curves produced by Dr. Ferguson indicated that an extremely small constant offset acceleration would account for the large displacement and the basic trend of the displacement curve.,
- 10. Free-Standing versus Anchored Racks:
The Issues:
"The new fuel racks, unlike the original racks, are free-standing and unfastened to the floor and walls of the pools".
Reference:
Paragraphs 10 and 11.
Response
Dr. Ferguson is concerned by the change to free-standing racks and states that, "The posibility of damaging collisions results directly from the replacement of racks which are anchored with new racks which are not anchored."
Free-standing spent fuel rack modules are not new to the nuclear power industry and continue to replace anchored fuel racks on an increased frequency concurrent with the industry's need to provide additional storage capacity for spent fuel at the plants.
The advantages of free-standing spent fuel rack modules over anchored racks include the following:
improved integrity of the spent fuel ifner, in that a multitude of o
rack anchor members penetrating the liner to be secured in the concrete pool structure are no longer necessary.
o the liner can be made smooth to better facilitate pool cleaning.
replacement of a rack module, should it be necessary following a fuel o
handling accident, for example, is simplified to the point that, after removal of the spent fuel assemblies, the module can easily be lifted out of the spent fuel pool and a replacement module installed with less hazard and exposure to personnel.
Plants other than Diablo Canyon, have been converting to free-standing spent fuel racks for many years. The following plants, for which I have participated in the review and evaluation of fuel racks for high density spent fuel storage, have received NRC approval to install free-standing fuel rack modules:
Oyster Creek Summer McGuire 1 and 2 St. Lucie 2 Turkey Point 3 and 4 Ginna Grand Gulf Millstone 2 Peach Bottom 2 and 3 __.
11.
Conclusion:
Following careful consideration of these seven issues associated with the structural analysis of the spent fuel racks and spent fuel pool that were raised by Dr. Ferguson, it is my professional opinion that the structural analysis of the racks and pool provided in support of the installation of high density fuel rack modules in the pools of Diablo Canyon Units 1 and 2 are adequate, and that the racks and the pool meet the structural criteria provided by the NRC. Therefore, it is my opinion that the structural adequacy of the free-standing spent fuel racks being introduced to Diablo Canyon will not reduce the margin of safety for the spent fuel storage system and will not increase the risk to the public health and safety or to the environment.
I hereby certify that the above statements are true and correct to the best of my knowledge, b 6nd { c
<ce-/r R. Clyde Herrick Subscribed and sworn to before me this ' day of June,1986.
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Program Management Mechanical Systems Design with Electronic / Hydraulic Control Product Development / Evaluation Structural Analysis Dynamic Response Failure Analysie R. CLYDE HERRICK, P.E.
PROFESSIONAL EXPERIENCE Mr. Herrick, a Principal Engineer in the Engineering Department, first joined Franklin Resarch Center in 1953. His present responsibilities include new program / project development as well as technical and managerial direction of continuing programs.
Mr. Herrick is also serving to focus and coordinate corporate actions with respect to the development of the Calspan Interchange Mechanism.
From 1969 to 1977, Mr. Herrick held several managerial positions with the Philadelphia Gear Corporation. As Assistant General Manager, Synchrotorque Division, he was responsible for technical direction and the formulation and execution of divisional plans and policy. Major contributions included standardization of commercial products, improvement of profitability and reliability, upgrading of electronic / hydraulic controls, and introduction of successful new products.
As Program Manager, Systems Division, Philadelphia Gear, he had primary responsibility for all phases of technical and administrative management of two multi-million dollar equipment development programs under the U.S. Navy's program management system, each including R&D, design, fabrication, and test-demonstration at sea of critical, complex, propulsion machinery. One program, that of successfully developing the world's highest performance super-cavitating controllable-reversible pitch, Marine propellers for the Navy's 100 ton SES-100B Surface Effect Ship, that attained 105 miles per hour during sea trials, required profound environmental and fabrication studies of candidate materials including inconel, precipitation hardening steels, and titanium alloys. The other program was for the Navy's DD-963 Spruance Class Destroyer Program, and covered the successful development and application of unique, logic controlled, automatic, forced-synchronizing clutch / brakes that delivered the power of four 22,000 HP gas turbines to the main propulsion system.
Previously, as a staff member at Franklin Research Center from 1953 to 1969, Mr. Herrick served as principal investigator for numerous research and development projects for government and industry, j
Specific experience in the nuclear power industry includes the following, some of which represent quick reaction assignments:
Herrick-1
o Monitored and evaluated the failure of the diesel engine crankshafts at the Shoreham Nuclear Power Station, including an evaluation of the corrective action taken. This was undertaken on a quick reaction basis.
o Reviewed the stress relaxation of the containment wall tendons and evaluated the tendon rock anchors of the Ginna plant.
o Reviewed and evaluated licensees' analyses for the introduction of high density spent fuel racks in the spent fuel pools of nuclear power generating stations. The analyses included two and three dimensional non-linear structural dynamics analysis of the spent fuel racks, wherein the fuel rack modules may lift off the pool floor during seismic events.
Participated with an NRC team in assessing the NRC's program for o
regionalization of licensing action reviews. This assignment included visits to each regional NRC office and evalubrion, for each region, of all aspects pertaining to the performance of licensing action reviews, o Conducted a technical review of 34 plant groups for the accident conditions of a main steam line break with continued feedwater. This program included an evaluation of the safety systems controlling feedwater and containment pressure, o Planned and conducted, on a quick reaction tasis, an extensive experimental random vibration study of the primary and secondary flow loops of the Advanced Test Reactor (ATR). This study identified the cause and indicated the required corrective action for severe tube vibration that damaged all four primary-to-secondary heat exchangers.
j o Pioneered the development of equipment qualification testing for electrical equipment in harsh environments, and performed the first known EEQ test after establishing a test facility for equipment qualification testing.
o Pioneered the use of the finite-element computer techniques for structural analysis of nuclear reactor components.
Developed early computer analysis techniques for volute pump casing o
structural analysis of large primary coolant pumps using the finite-element approach. The computer method served as an interim analysis standard for the AEC.
o Reviewed structural analyses of nuclear reactor components for the 3
Loss of Fluid Test (LOFT) program.
o Performed an analytical investigation of the instability of fuel rods within a chevron fuel module.
Herrick-2
Participated in the pioneering development of shipping containers for o
spent nuclear fuel elements, with emphasis upon fabrication, structural integrity, and accident survivability, o Contributed structural analyses and the development of analysis methods toward the design of the Enrico Fermi and EBR II breeder reactors.
Representative projects for government and industry:
o Consulted in machine / structural diagnostics, vibration, critical instrumentation, system response, and failure analysis.
Performed dynamic system simulations, including flywheel-stored energy o
for airplane catapult systems, an ammunition transfer carrier mechanism, a reversing drive for ship propulsion systems, and industrial variable-speed drive systems.
Performed a broad study of methods, systems, attainable accuracies, o
and costs of in-motion highway vehicle weighing.
o Developed elastomeric bea*.ings for helicopter rotor hinges, including formulation of special silicone elastomers.
o Performed extensive analysis of stiffness, and of design and fabrication methods, of multiple reduction gear drives for large radar antenna and radio telescope drive systems to achieve the accuracy requirements of servo antenna positioning systems (three programs).
o Evaluated methods for thawing frozen coal in railroad hopper cars, o Performed mechanical systems diagnostic services for industry, combining analytical and experimental methods.
ACADEMIC BACKGROUND Pennsylvania State University, BSME, 1953 University of Pennsylvania, MSME, 1958 University of Delaware Extension, 30 Graduate Semester Credits University of Pennsylvania, Completed course work toward Ph.D. (1966)
PUBLICATIONS Mr. Herrick has published more than 55 research and development reports, A'hE papers, and several trade journal articles.
S Herrick-3
9 PATENTS Self-Synchronizing Clutch, U.S. Patent #4,053038 Patent applied for in Germany, United Kingdom, Switzerland, and Japan Other disclosures for which applications have not as yet been made.
REGISTERED PROFESSIONAL ENGINEER Pennsylvania PROFESSIONAL SOCIETIES American Society of Mechanical Engineers Societysof Naval Architects and Marine Engineers National Society of Professional Engineers Society of Experimental Stress Analysis Sigma Xi (Research Society of America)
Sigma Tau (All-Engineering Honorary)
Pi Tau Sigma (Mechanical Engineering Honorary) 1 O
e e
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