ML20150F079
| ML20150F079 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 03/30/1979 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Whitmer C GEORGIA POWER CO. |
| References | |
| TAC-11158, NUDOCS 7904180008 | |
| Download: ML20150F079 (5) | |
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UNITED STATES j
NUCLEAR REGULATORY COMMisslON
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MARCH 3 0 ST9 Docket No. 50-366 Mr. Charles F. Whitmer V1.ce President - Engineering Georgia Power Conpany P. O. Box 4545 Atlanta, Georgia 30302
Dear Mr. Whitmer:
By your letter dated December 1,1978, you proposed Technical Specification changes for settlement of Class I structures on. Hatch Nuclear Plant Unit No. 2.
During the course of our review we have determined that the additional informatiori identified in Enclosure 1 is required.
Our review has identified a significant iten of difference between,
the staff's requirement and your submittal.
This difference relates to the currently approved specification which requires ' shutdown should the field measured settlements exceed the allewable settlement values.
Your requested amendment would delete shutdown action based on your statement that this requirement is unnecessary and overly severe because of the slow pace at which settlement could be expected to occur and where remedial action could be taken. The staff's position on this item is indicated in Enclosure 2.
In order to prcvide for timely completion of our review we request that a revised subnittal which includes the additional infomation identified in Enclosure 1 be provided within 30 days of your receipt of thi s l ett.er.
Further, your submittal should include a revised Technical Specification as discussed in Enclosure 2 or justification for deviating from the staff position.
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. Mr. Charles F. Whitmer 2-Stould you have any questions, please contact us.
Sincerely, Thoma[)!N)!2<~bt-CV Ippolito, Chief e
Operating Reactors Branch #3 Division of Operating Reactors
Enclosures:
1.
Request for Additional Infomation 2.
Staff Position on Technical Specification change request cc w/ enclosures:
see next page l
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Georgia Power Company Oglethorpe Electric flembership Corporation flunicipal Electric Association of Georgia City of Dalton, Georgia cc:
G. F. Trowbridge, Esquire Shaw, Pittnan, Potts and Trowbridge 1600 M Street, N. W.
Washington, D. C.
20036 Ruble A. Thomas Vice President P. O. Box 2625 Southern Services, Inc.
Birninghan, Alabama 35202 fir. Harry 11ajors Southern Services, Inc.
300 Of fice Park Birminghan, Alabana 35202 Mr. C. T. Moore Georgia Power Company Power Generation Department P. O. Bor, 4 54 5 Atlanta, Georgif 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 Conmission P. O. Box 710 Baxley, Georgia 31513
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ENCLOSURE 1 REQ' JEST FOR ADDITIONAL INFORMATION GEORGIA POWER COMPANY EDWIN I. HATCH NUCLEAR PLANT UNIT NO. 2 "SETTLEMENT OF CLASS I STRUCTURES" 1.
The labeling of benchmarks on submitted settlement records (FSAR, Fig. 2A-16A, sheet 1 through 5) should be revised and resubmitted to permit correlation with new benchmark designations indicated on the proposed Technical Specific.ation Tables.
2.
Provide the surveyed reference elevations for each benchmark i n Ta bl e 3. 7.8.2-1.
Provide the results of the comparison which was nade between allowable versus measured settlement that is discussed in Paragraph 4.3 (Enclosure to Georgia Power December 1,1978 letter entitled, "Supporting Information for Proposed Technical Specifications, Settlement of Class I Structures"). We request the actual computations which estab-lished the allowable differential settlement in Table 3.7.8.2-1 between benchmarks 1 and 2 (0.033') and benchmarks 1 and 3
( 0.13 9 ' ).
3.
Many of the allowable differential settlement values estimated for the Control Building, Turbine Building, Diesel Crierator Building and Intake Structure are so large because of the adopted settlement criteria that they exceed total predicted settlement values where notification of the NRC would have been required.
We recommend in order to highlight the controlling settlement criteria that an explanatory note be added to distinguish those allowable differential settlement values in Table 3.7.8.2-1 which are superseded by a more limiting settlement criteria.
The referenced note should indicate what Technical
<cification Table contains the controlling settlement value.
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EtiCLOSURE 2 STAFF POSITI0tl Ori SETTLEMEfiT OF CLASS I STRUCTURES E0Witi I. HATCH fiUCLEAR PLAT 1T UtilT tiO. 2 Position:
The.f4RC staff requires the following statement be added to Sections l
3.7.8.2, 3.7.8.3 and 3.7.8.4 of the Technical Specifications under I
heading ACTI0ti:
"With the differential settlement of any structure exceeding the allowable differential settlement value of Table (insert appropriate table), be in at least HOT SHUTDOWii within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUT 00Wfi 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.
Discussion:
1.
Computations establishing the allowable differential settlement values in the Technical Specification tables are based on somewhat conservative but reasonable design assumptions.
These settl ement.s.
if exceeded because of unanticipated conditions, could result in undesirable distress to Class I structures and conduits.
The current trend reflected by actual field settlement measurements indicates that settlements have leveled off and that the proposed allowable values should not be experienced during the years 'of plant operation.
However, if unanticipated foundation conditions were to develop and result in an unusual resumption oi settlement, it is the staff's position that there should be a maximum settlement limit beyond which shutdown and physical inspection of Class !
pipelines, connections, and structures would be required.
2.
The Technical Specifications as proposed by the licensee require an engineering review and evaluation for submittal to the fiRC if the reasured dif ferential rettlement exceeds 75% of the allowable settlement value.
It is the staff's position that the results of this study could permit shutdown to be avoided if a reasonable explanation for the continuing settlement were provided and remedial action was shown not to be necessary.
3.
The requirement for shutdown strongly encourages both the licensee and NRC to address an unanticipated developing settlement problem in a timely manner.
Lengthy technical studies requiring detailed review while the settlement oroblem goes unstated should be avoided.
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