ML20028E436
| ML20028E436 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 01/06/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20028E434 | List: |
| References | |
| NUDOCS 8301260030 | |
| Download: ML20028E436 (3) | |
Text
r DIABLO CANYON, UNIT 1 SAFETY EVALUATION REPORT yy letter dated December 21, 1982 the Pacific Gas and Electric Canpany (PG&E) requested relief from Section 3/4.9.7 of the Diablo Canyon, Unit 1 Technical Specifications for a period of 120 days in order to make certain modifications in the Fuel fiandling Huilding. Section 3/4.9.7 of the Technical Specifications prohibits the povement of loads in excess of 2,500 pounds over the spent fuel pool while fuel assemblies are being stored in the pool.
EVALUATION As a result nf the independent design verification program, certain modifications are required to be made to the Fuel Handling Building superstructure in order to assure that the building is designed in accordance with the FSAR commitments.
In performing these nodifications, there is the potential for dropping objects into the dry Unit I spent fuel pool which presently contains unirradiated fuel assemblies which have been stored there since 1976. To preclude an object from falling into the dry spent fuel pool and possibly damaging the unirradiated fuel asseoblies, PGSE has proposed to install steel covers over the Unit 1 spent fuel pool until the necessary modifications have been completed. ' The covers are comprised of two 1/2" thick steel plates each of which weighs approx-inately 11 tons and one smaller steel plate cover which weighs approximately 2 1/2 tons. Since each of the steel plate covers weigh in excess of the 2500 pounds naximum pernissible load to be noved over the spent fuel pool by Section 3/4.9.7 of the Technical Specifications, PG&E has requested relief from this technical specification for a period of 120 days.
The sizing of the steel plate cover was based on preventing the heaviest identified object, which weighs approximately 500 pounds, from-penetrating the proposed cover.
The Fuel Handling Building Crane, which has 'a design rating of 100 tons, will be used to transfer the steel plate covers from the temporary storage at a height '
of 1" above the spent fuel pool side rail tracks as they are moved into position.
The sane procedure will be used when removing the covers.
Established maintenance procedures for testing and maintaining the Fuel Handling Building Crane will be adhered to.
The two larger steel plate covers contain angle restraints along the sides, in the direction of travel along the pool side rail tracks, to further preclude the potential for dropping (sliding) these covers into the pool while they are being positioned over the pool.
The requirements of CAL OSHA in regard to the rigging and lifting of loads will be complied with, as appropriate, and operations of the crane will be done by qualified and experienced personnel.
The rigging that will be used to move the covers will have a safety factor of 10.
The foregoing neasures and procedures provide assurance against the inadvertent dropping of the steel plate covers into the pool.
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lI The introduction of borated or unborated water into the spent fuel pool with the fuel assemblies in their present geonetry would not result in criticality.
The dropping of an object on the fuel assemblies in the dry spent fuel pool will not cause criticality.
Criticality could only occur if the fuel racks were deforned in a manner that would decrease the distance between the fuel assenbiles to form a critical geometry in the presence of water.
To further preclude this possibility, the three systens that provide water to the fuel storaqe area (Prinary Water, Fuel Pool, t'akeup Water, and Fire Water to the hose reel stations) will be valved off and tagged inoperable. Following the installation of the covers, the Fire Water valves will be returned to their original valve position and tags renoved. Prior to removing the covers the Fire Water will again be temporarily valved off and tagged inoperable. We find that above precautionary measures to prevent damage to the fuel assemblies and consequent criticality are acceptable.
i Et VIR0t#tEtlTAL C0flSIDERATI0f!S The imC staf f has determined that this amendment does not authorize a change in effluent types or total amount nor an increase in power level and will not result in any significant environnental inpact. Ifaving made this determination, 7
we have further concluded that this anendment involves action which is insignifi-cant from the standpoint of environmental impact and pursuant 10 CFR Section 51.5 (d)(4), that an environnent31 inpact statement or negative declaration and environcental inpact appraisal need not be prepared in connection with the
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issuance of this anendment.
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Cof:CLUSI0ft Hased upon our evaluation of the proposed changes to the Diablo Canyon, Unit 1 Technical Specifications, we have concluded that:
(1) because this amendnent does not involve a significant increase in the probability or consequences of accidents previously considered, does not create the possibility of an accident of a type different from any evaluated previously, and does not
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involve a significant decrease in a safety nargin, this amendment does not involve a significant safety hazards consideration; (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed nanner, and (3) such activities will be con-ducted in compliance with the Comission's regulations and the issuance of this anendment will not be inimical to the connon defense and security or to the health and safety of the public.
Ue, therefore, conclude that J
the proposed ch0nge is acceptable.
Dated: JAN 6 1983
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1 The ' introduction of borated or u norated water into the spent fuel pool with
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thp fuel aneraltes in their' present yeonetry would not result in criticality.
The dropping of an object on the fuel asseichlies in the dry spent fuel pool will_not cause criticality. Criticality could only occur if the fuel racks were deforned in a nanner that would rtecrease the distance between the fuel assenh11es to torn a critical qeonetry in the presence of water.
To further preclu/le this possibility, the three systens that provide water to the fael storage arco (Primary Pater, Fuel Pool, Makeup Water, and Fire Water to the hose reel stations):will be valved off and tagged inoperable. Following the installation of the covers, the Fire Water valves will be returned to their original valve position and tags renoved. Prior to recoving the covers the Fire Water will again be teaporarily valved off and tagged inoperable. De find that (bnve precautionary acasures'to prevent danaqe to the fuel assemblies dQ are accent'able.
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ENVIRpfcpTALCONSIDE7ATIONS
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The P C staff has determined that this anendt: Ant;_does not authorize a change in effluent t,/nes or total anount nor an increase in power level and will not resuit-in any significant envirorm. ental inpact, fiaving r1ade this determination, M have further concluded that thic amendment irNulves action which is insignifi-cent from the standpoint of enviromental inuact and pursuant 10 CFR Section 51.5 (d)(4), that an environnental impact statement or negative declaration and environmental inpact appraisal need not be prepared in connection with the issuance of tnis arrendment.
CONCIUS10H j
Pased upon our evaluation of the proposed changes to the Diablo Canyon, Unit 1 Technical Specifications, we have concluded that:
(1) because this anendment does not involve a significant increase in the probabilizy or consequences of accidents previously corisidered, does not create the possibility of an accident,of a type different from any evalusted previously, and does not involve a significant decrease in a sefety r:iargin, this amendment does not involve a significant safety hazards considdration; (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed r"anner, and (3) such activities will be con-ducted in compliance with the Comission's requlations and the issuance of this anendnent will not be inimic'al to the comon defense and security or to the health and safety of t'ie public.
We, therefore, conclude that the proposed change is acceptstile, a
Dated:
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