ML20049J682
| ML20049J682 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 03/11/1982 |
| From: | Wuller G ILLINOIS POWER CO. |
| To: | John Miller Office of Nuclear Reactor Regulation |
| References | |
| N88-82(03-11)-6, N88-82(3-11)-6, U-0435, U-435, NUDOCS 8203190205 | |
| Download: ML20049J682 (5) | |
Text
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U-0435 ILLINDIS POWER 00MPANY : gg ggg_ggz03_11y.5 fM 500 SOUTH 27TH STREET, DECATUR, ILLINOIS 62525 March 11, 1982 os Mr. James R. Miller, Chief 8
Standardization & Special Proj ects Branch Ni'CIifMED fgOl 8 [ggg,, '~
Division of Licensing Office of Nuclear Reactor Regulation
,kfmgge %e U.S. Nuclear Regulatory Commission E
g%4m Washington, D.C.
20555
//
Dear Mr. Miller:
Reference:
Illinois Power letter 1/20/82, U-0403 G. E. Wuller, IP to James R. Miller, NRC, regarding Degraded-Core Hydrogen Control Clinton Power Station Unit 1 Docket No. 50-461 As agreed upon in a telephone conversation with Dr. C. P. Tan of NRC on February 23, 1982, we are forwarding to you the revised responses of questions 2, 3, and 4 on the subj ect of containment ultimate capacity.
Our original responses to these questions were provided via the referenced letter.
The attached revisions are as discussed and agreed with Dr.
C. P. Tan.
Please let us hear if you have any question on this material.
Sincerely, G. E. Wuller Supervisor-Licensing Nuclear Station Engineering JHS/lt cc:
J. H. Williams, NRC Clinton Project Manager H. H. Livermore, NRC Resident Inspector W. R. Butler, NRC CSB N.
C. Chokski, NRC SEB C. P. Tan, NRC SEB 6
8203190205 gyng,,
,{z DR ADOCK 05000461
\\
Revision 3/11/82 Question #2 If instead of using the 1971 edition with 1971 addenda the latest 1980 edition of the ASME B & P V Code Section III Division 1 is used, what will be the buckling capacity of the equipment hatch spherical head?
Reponse,:
The basic compressive allowable stress, determined in accordance with NE-3222.1(b), does not change if the latest 1980 edition of the ASME B & PV Code Section III Division 1 is used instead of 1971 edition.
In determining the 76 psig ultimate static pressure capacity of equipment hatch, which is limited by buckling of the spherical head, twice the basic compressive allowable stress was used.
At 76 psig the compressive stress in the head is 8300 psi against the minimum yield stress of 34,600 psi for the material.
The ASME Code does not address the allowables for an ultimate capacity determination.
However, if the allowables for Level D Service Limits are used from 1980 Code, NE-3222.2(c), the capacity of the head against buckling will be 57 psig.
We believe that for ultimate capacity determination, it is more appropriate to use twice the basic compressive allowable stress, permitting 76 psig, rather than the allowables for Service Level D, 1980 code.
It should be noted that the basic ASME allowable is based on capacity reduction factors determined from lower bound values of test data.
These facters account for imperfections in the shell, both local and of a general nature.
This is documented in ASME Code Case N-284.
Revision 3/11/82 Question #3:
On the basis of the pressure resisting capacity of the seals, around personnel lock equipment hatch and other access pene-tration indicate what the containment ultimate capacity will be.
Response
The airlock doors and equipment doors are pressure seated.
They are the same basic design and similar materials that have been used on pressurized water reactor plants which would employ a higher design pressure for the containment vessel.
CB&I has successfully used this type closure on the SNUPPS Containment which was designed for a pressure of 60 psig and tested at 69 psig with no apparent leakage.
We would expect that the amount of leakage through these seals at 76 psig containment pressure would be generally within the leakage rate for the design pressure (15 psig).
The seal material should not degrade for temperatures up to 300 F.
m
Revision 3/11/82 Question #4 In figure A-1 Section 3-3 in the containment mat marked as critical section.
In staff's judgment the cylinder section adj acent to the foundation mat may be more critical.
Provide an evaluation of this section.
Response
Figure A-1 was meant to show only the critical section in each of three regions:
mat, cylinder and dome.
Meridional stresses in the cylinder adjacent to the foundation mat are indeed higher than in the mat itself.
However, the hoop stress in the cylinder section at approximately midheight is the most critical.
The cylinder section near the mat is not as critical because the hoop stress in that section is smaller than at the midheight of the cylinder due to the meridional reinforgement at the section being creater than at midheight of the cylinder.
Maximum stresses in the cylinder adjacent to the mat (considering the liner for strength) are:
Tension in meridional reinforcement =62ksiff(F7 = 71.1 ksi)
Compression in concrete = 3550 psi (3fc
= 6086 psi)
Maximum strain in the cylinder. liner adj acent to the mat is:
Tensile strain in liner = 0.0030 in./in. (less than 0.01 in./in. ASME allowable)
The meridional and hoop reinforcement in the cylinder sectirns near the mat and near midheight are shown in the following sketchec.
1. "-
,CYLIMDZR REI::FO2CE *.E:IT
(
I
/
O-Meridional Iloop f
- 18 0 12"c x # 18 @ 12" 3 6,,
O G
-hinar J-Meridional Section Near Dr"cmat f.
t
- 18 0 12"',/
O Iloop N.
Meridional
- 18 9 12" 36"
/
o 1--Liner
.z, Meridional Section IIcar Midheight O
_2_
-