ML19256F530
| ML19256F530 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 11/27/1979 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Whitmer C GEORGIA POWER CO. |
| References | |
| TAC-11158, NUDOCS 7912190343 | |
| Download: ML19256F530 (4) | |
Text
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UNITED STATES
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November 27, 1979 Docket No. 50-366 Mr. Charles F. Whitmer Vice President - Engineering Georgia Power Company P. O. Box 4545 Atlanta, Georgia 30302
Dear Mr. Whitmer:
We are prcceeding with our review of your submittals dated December 1,1978, August 14, 1979, and October 8, 1979 regarding proposed Technical Specifica-tion changes for settlement of Class I structures on Hatch Nuclear Plant Unit No. 2.
We have determined that the additional information requested in the enclosure to this letter will be necessary in order to complete our review.
In order to provide for timely completion of our review, we request that a submittal including the additional information identified in the Enclosure be provided within 30 days of your receipt of this letter.
Should you have any questions, please contact us.
Siliceyely, vf (N?&lLM P
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Thomas A. Ippolito, Chief Operating Reactors Branch #3 Division of Operating Reactors
Enclosure:
Request for Additional Information cc w/ enclosure:
See page 2
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1620 267 7 912190.3 4 3
Mr. Charles F. Whitmer Georgia Power Company cc:
G. F. Trowbridge, Esquire Shaw, Pittman, Potts and Trowbridge 1800 M Street, N. W.
Washington, D. C.
20036 Ruble A. Thomas Vice President P. O. Box 2625 Southern Services, Inc.
Binningham, Alabama 35202 Ozen Batum P. O. Box 2625 Southern Services, Inc.
Birmingham, Alabama 35202 Mr. William Widner Georgia Power Company Power Generation Department P. O. Box 4545 Atlanta, Georgia 30302 Mr. L. T. Gucwa Georgia Power Company Engineering Department P. O. Box 4545 Atlanta, Georgia 30302 Appling County Public Library Parker Street Baxley, Georgia 31413 Mr. R. F. Rogers U. S. Nuclear Regulatory Commission P. O. Box 710 Baxley, Georgia 31513
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,_.,N Section A.2 - The benchmarks shown in Figure A.1-1 are all located outside of the critical buildings.
Describe the procedure followed to tie the elevations of the inside benchmarks into the system of outside benchmarks.
Describe the original procedure and the periodic checking procedures.
Section A.4 - Provide a table listing of all benchmarks installed in the walls of the critical structures and their distances to the floors of the same structures.
Section B
- (a) We assume that your statement about the 3 inch gap you mention which has been established at the top of the buildings in the powerblock means that an open space 3 inches wide exists between any two buildings.
Confirm that our understanding is correct and descr.ibe the procedure which you will use to inspect the gap during the operating life of the facility.
(b) You describe in Section B and show in Figure B.1-1 a flexible connection with a 3/4" maximum range for differential settlement. Demonstrate that this range is sufficient even when extreme enviranmental conditions occur such as safe shutdown earthquake, floods, etc.
(c) The limiting values of settlements are also a function of soil properties, size of the foundations, etc. and not only of structural considerations.
The design of structural elements should take into account the necessity for structural elements to absorb safely the differential settlements.
If the limiting values of settlements, at end of operating life of the facility, are such that they exceed the capacity of structural elements to absorb them, a very dangerous situation may be created. Demonstrate that the values of diff-erential settlements at age 40, incorporated into the design, will not be exceeded in actual circum-stances.
(d) Our main concern with tilting is whether all the equip-ment involved in limiting the consequences of LOCA type accident will perform as expected.
Furnish a list of this equipment, the allowable tilt for each piece, and the procedures devised for checking that the actual tilting is below the allowable.
Section D
- Penetration Differential Settlements Indicate the safety margins provided in anchors and penetra-tions for the case when the observed settlements are exceeded.
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ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION REVIEW 0F PROPOSED CHANGES TO HATCH UNIT NO. 2 SPECIFICATION ON SETTLEMENT OF CLASS I STRUCTURES (DOCKET #50-366)
We have reviewed all the information provided by the licensee to date including answers to our questions. We have also noted the changes in Technical Specifica-tion, required by NRC staff, worded as follows:
" Position:
The NRC staff requires the following statement be added to Sections' 3.7.8.2, 3.7.8.3 and 3.7.8.4 of the Technical Specifications under heading ACTION:
'With the differential settlement of any structure exceeding the allowable differential settlement value of Table (insert appropriate table), be in at least HOT SHUTDOWN within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the next 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />'.
The addition of this statement is not required in Section 3.7.8.1."
In order to be able to prepare our evaluation and to comment on suggested changes in the Technical Specification, we still require the following additional infor-mation from the licensee:
Report attached to Georgia Power Company letter to NRC dated October 8,1979 General Our main concern is with possibly very rapid changes in the state of the structures and equipment.
It is well known that strain energy slowly accumulating in the various elements of the facility may be brusquely released by extra fast crack propagations, Provide technical bases to address this concern.
Section A,1 - (a) Figure A.1-1 does not include a scale.
Provide a graphic scale which will give us the possibility to evaluate the relative distances.
(b) Your. responses state that there is no procedure for perio-dically checking the elevations of the reference benchmarks and the basic reference benchmark.
Provide such a procedure, especially for the case where the benchmarks r.ay have been displaced such as an earthquake.
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