ML20214G717
| ML20214G717 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 11/19/1971 |
| From: | Case E US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| CON-WNP-0155, CON-WNP-155 NUDOCS 8605220435 | |
| Download: ML20214G717 (11) | |
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e NOV 19 E71 Peter A. Morria, Director Division of Reactor thing EAMFDED # 2 NUcTEAR PLANT, DOCKET NO. 05000 397 UASRINGTON PUBLIC POWER SUPPLY SYSTEM Adi:quate responses to the enclosed request for additional information are retuired before we can complete our review of the subject application.
These requests, prepared by the DRS Structural Engineering Branch, concern the Class I structural design material presented in Sections 5 and 12 of the PSAR. Consultant comments have not yet been received.
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E. G. Cu Edson G. Case, Director Division of Reactor Standards
Enclosure:
Request for Additional Information for Hatch Nuclear Plant Unit No. 1 cc w/ enc 1:
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O HANFORD #2 NUCLEAR PLANT DOCKET NO. 05000 397 REQUEST FOR ADDITIONAL INFORMATION I.
CLASS I STRUCTURES OTHER THAN CONTAINMENT
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1.
In order to permit evaluation of Class I and Class II structural interactions:
(a) Indicate the criteria used for arranging and designing Class II structures in such a way that adjoining Class I structures will not be damaged by Class 11 structures during an OBE or DBE.
(b) Since the turbine building is designed for seismic zone 2, it is. assumed that the building will not be designed to fully withstand the OBE or DBE.
Explain the methods of design and construction used to ensure that the turbine building will not damage Class I structures or equipment located inside or adjacent to it.
e 2.
Specify the strength theory used for establishing the appropriate safety margin for the structural steel of Class I structures (other than steel containment) where two o r three dimensional stress conditions may exist.
3.
Present the criteria for "no loss of function" for all structures required for safe shutdown and submit a list of all such structures.
. Where structural deformations are the controlling criterion for Class I structures, explain how it is applied to these structures and list the acceptable deformation limits.
4 For reinforced concrete structures indicate the allowable stresses for shear, bond, and anchorage of reinforcing bars, considering uni-bi-or tri-axial stress distributions.
5.
The AISC specifications and the ACI-318 Code are applicable only to framed structures. Justify your use of these documents for structures other than framed structures.
6.
Indicate the provisions made to protect large openings, such as doors in the diesel-generator building, against tornado and tornado generated udssiles.
7 Present a list of typical missiles which have been considered in the design, and indicate the nature of the udssile, the weight mass / cross-section ratio, shape, assumed point of impact, ass umed impact velocity, and where and how originated. Indicate the criteria and the method of analysis used for checking the structure at point of impact. Indicate whether all Class I structures or part of structures have been checked for impact of missiles. Indicate whether the crane can generate internal udssiles which may endanger the containment s tructure.
8.
Describe the provisions made to tie down all removable slabs, blocks, or partitions to prevent them from becoming udssiles.
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9.
During an OBE and a DBE, torsional loads will be applied even to symmetrical structures (see the paper by N. M. Newmark, " Torsion in Symmetrical Buildings," Fourth World Conference on Earthquake Engineering, Santiago, Chile, 1969). Indicate whether torsional ef fects are considered for the containment, the internal s tructure, and other symmetrical and nonsymmetrical Class I structures.
Indicate the structural elements which carry these loads and demonstrate that the corresponding critical stresses meet the criteria for allowable design stresses.
10.
Describe tie down arrangements made for all Class I equipment to resist seismic and tornado forces. Restraints provided for equip-ment usually have gaps between them and the equipment. Indicate whether the seismic analysis considers these gaps and evaluate the impact forces, due to the gaps, acting on the equipment, the restraints and the structures. Refer for instance to: " Dynamic Analysis of Mechanical Systems with Clearances" Part I - Formation of Dynamic Model. Part II - Dynamic Response by Dubowsky, C. and Frudenstein, F., Jour. Engin. Industry, Trans. ASME 93(1) Feb. 1971.
- 11. To evaluate the design adequacy of the fuel pool floor and walls to withstand the ef fect of a f uel cask drop, submit the design criteria and applicable analyses used in the design of the walls and the floor. Indicate the maximum thermal stresses which can be developed
. in the spent fuel pool walls under the nost adverse conditions.
Describe what provisions have been made to control cracking in this s tructure. In the design consider combined stresses due to the worst load combination.
12.
The following information is needed to properly evaluate the structural adequacy of the concrete biological shield wall around the drywell:
(a) Discuss the loading combination DL + LL + P + TilERM + RESTR +
R + H + OBE (or DBE), at anchor points of the equipment and piping where R = jet reaction of piping and equipment and H = thermal reaction of piping and equipment.
(b) Discuss the venting and drainage system of the gap between drywell and shield wall and the possible undue pressurization of the gap due to high temperature in the drywell, which in turn could impose external loadings on the drywell.
(c) Discuss the thermal gradient in the biological shield, when the temperature inside the drywell may possibly reach as high as 350*F.
(d) Specify the design criteria and design details for large openings in the shield wall. Justify the use of allowable stresses highr.r thar permitted by the ACI Code, and explain the method used for the analysis for non-axisymmetric loads.
. 13.
Present a summary of the design of the reactor pedestal:
(a) Present the method used to include thermal gradients (transient and steady state) in the vertical and radial directions. Justify the use of allowable stresses higher than permitted by the ACI Code.
Ob) Describe the design of the ring girder and the anchor bolts connecting the reactor skirt with the steel ring girder on top of the concrete pedestal, and the anchor bolts connecting the ring girder to the pedestal including a discussion of the transmission of horizontal forces from the reactor skirt to the ring girder and from the ring girder to the concrete.
Evaluate the safety factors provided if no friction is assumed to act in tae interfaces of skirt to ring girder and in the interface af ring girder to concrete.
(c) Evaluate 8.a) the stresses in the shear reinforcing connecting the base of the concrete pedestal to the ellipsoidally shaped concrete base, and (b) the shear ring connecting the ellipsoidally shaped concrete base to the steel drywell, assuming that there is no friction acting between the concrete and the steel.
(d) Evaluate the safety factor provided in the connection between the bottom of the steel drywell and the concrete foundation, neglecting friction.
. 14 Describe the seismic design of elements connecting the reactor building to other buildings with dif ferent dynamic characteristics.
Compare the structural separations with anticipated seismic move-t I
ments of the structures.
I 15.
The forces on structures due to thermal expansion of pipes and/or equipment under operating conditions change during a loss-of-coolant accident. Explain on what basis these forces have been established for accident conditions. Indicate the corresponding loading combinations and the nominal safety factors used in the design of the structure for these conditions.
16 Give examples of the design of the reactor building floors, walls and steel superstructure: (a) explain the design method for con.
centrated loads such as jet forces, equipment reactions and missile impact, (b) describe concrete crack control and how earth-quake torsion was handled in design, (c) discuss the probability that only part of the reactor building siding will be blown away and indicate how this case has been provided for in the main steel framing of the building, and (d) indicate the impact factor used in designing for the drop of a fuel cask.
17 (a) Indicate the design criteria and the design methods for the biological shielding and other concrete at points of support for pipe and valve structural anchors. Also, furnish the same information for anchorages to structural steel supports
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. (b) Indicate design methods and design stress criteria applicable to the main steam line anchor separating the Class I f rom the Class 11 part of the main steam line.
18.
Describe the design criteria, methods, and type of Inads and design safety f actors for the structures of the sacrificial shield and the main steamline enclosure.
- 19. Indicate in sketches the provisions made to test the leaktightness of the penetration and field-welds, including the welds connecting the penetration sleeves to the drywell shell.
20.
Provide sketches showing the construction details of the reactor building locks and indicate the design criteria and design methods, especially for seismic loads, and furnish the test procedures.
21.
Provide sketches of typical pipe, cable and duct penetrations in the reactor building. Indicate the testing methods and the tornado protection for the penetrations into the reactor building.
22.
Describe the design criteria applied and provisions made to prevent the collapse of block walls between cells during an earthquake and to preclude damages to Class I equipment adjacent to them.
II. DRYWELL AND PRESSURE SUPPRESSION CHAMBER 1.
In order to evaluate the actual safety factor in the containment design, furnish the following:
6 (a) A discussion of the long term (through 10 seconds) thermal gradients that will be established in the steel and concrete L.
. portions of the containment following the design basis loss of coolant accidents under conditions during the functioning of containment heat removal systems.
(b) Identify the pipe sizes of design basis breaks which result in the most severe thermal gradients being established in critical areas of the containment such as steel shell, concrete walls, base mat-to-steel joint, drywell floor-to-wall joint, reactor vessel concrete support, and steel containment head closure.
Submit a list of safety factors (in terns of ratio of allowable stress to calculated stress) for these critical areas, based on the combination of coincident thermal and pressure loadings which may exist at the time when the most severe thermal gradients are developed as well as during plant startup and shutdown periods, and which may result in critical stresses.
2.
Demonstrate by analysis that the removable, segmented, reinforced concrete shield plug above the drywell is capable of resisting the impact of the postulated udssile with the greatest impact energy, and that it cannot itself become a missile, or a group of missiles, and damage the drywell. Describe also the effect of operating and accident thermal loads on the shield plug.
3.
Explain the method of analysis and the strength criteria used for the seismic design of the connections between the personnel and equipment locks and the drywell shell. Explain the provisions made
k to take care of differential motion and expansion of concrete and the steel shell. Explain the influence of complete local encase-ment of the drywell in concrete on the scismic design.
4 List separately the elements of the pressure mmpression support system designed by the ASME B and PV Code,Section III, and the structural elements designed by AISC specifications. Indicate what sections of each Code have been used and list the respective allowable design stress criteria applied.
5.
Describe the physical characteristics of the filler between the drywell and shield wall, especially the extent to which it can be compared with the expansion required of the drywell. Include the effects of permanent set of the material af ter several cycles of normal drywell thermal expansion. Discuss increased steel plate buckling potential due to the gap filler material and the base transition zone encasing concrete.
6.
Since the dividing floor between the drywell and the suppression chanber is a conventionally reinforced concrete floor and is supported by the center pedestal and a series of columns, provisions are necessary to accommodate the required differential motion for thermal, seismic effects, etc.
It is not clear from the description given what seal between the floor and the containment steel wall will be provided. Describe the details of such a seal or other means to accommodate the required dif ferential motion.
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- III.
Testing 1.
State the design pressure differential across the inter-mediate floor within the containment.
Indicate whether initial and subsequent testing of the floor with regard to strength and leakage will be performed, and the manner in which it.will be executed.
Specify the maximum allow-a le leakage without resulting in an excess of design pressure of either the drywell compartment or the pressure suppression chamber compartment.
Also specify the design leakage through the floor and the seal, including the bases upon which these leakage values are determined.
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