ML19344A900
| ML19344A900 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/26/1978 |
| From: | Parker W DUKE POWER CO. |
| To: | Case E Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19344A901 | List: |
| References | |
| REF-GTECI-A-36, REF-GTECI-SF, TASK-A-36, TASK-OR NUDOCS 8008220498 | |
| Download: ML19344A900 (1) | |
Text
DUKE' POWER COMPA.NY Powra Britotxo 422 SouTn Cucacu SrazzT, CruntorTE, N. C. 2e242 w i L LI A M O. PAR M ER, J R.
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5-t a =a Pace.c? cm 3 ' 3-4 93 June 26, 1978 THIS DOCUMENT CONTAINS Mr. Edson G. Case, Acting Director P0OR QUAllTY PAGES Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
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Reference:
Oconee Nuclear Station Docket Nos. 50-269, -270, -287
Dear Mr. Case:
In a letter dated May 17, 1978 from Mr. V. Stello, NRC/ DOR, the staff requested additional information with regard to licensee procedures and plant systems for the movement of heavy loads near spent fuel.
Duke Power Company has previously exchanged information relating to
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this concern with the staff. This correspondence was documented in 7
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the Safety Evaluation supporting Amendment Nos. 32, 32, and 29 to I J Facility License Nos. DPR-38, -47, ~55, respectively, a copy of which #
is attached.
Duke Power Company considers therefore that this concern has been sufficiently addressed and that no further response in this matter is required.
Ve y truly yours,/
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William O. Parker, Jr. '*
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SAFETY EVALUATION AND ENVIRO'" ENTAL IMPACT APDRAISAL L-t BY THE OFFICE OF NUCLEAR REACTOR RECULATIO:.
$1c' SUPPORTING AMEND"Z1T NO. 32 TO FACILITY LICE"SE NO. CPR-33 AMEND"ENT NO. 32 TO FACILITY LICENSE NO. DPR a7 AMEND l'ENT NO. 29 TO FACILITY LICENSE NO. DPR-E5 DUKE POWER COMPANY r--
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OCONEE NUCLEAR STATION, UNITS NOS.1, 2 AND 3 DOCKETS N05. 50-269, 50-770 AND 50-287 Introduction a
By letter dated August 20, 1976, Duke Power Company (the licensee) reauested
,. ;f a change to the Technical Specifications accended to Licenses Nos. DPR-3E, DPR-47 and DPR-55 for the Oconee Nuclear Station Units Nos.1, 2 and 3.
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amendments would require that spent fuel assemblies ctored in designated areas of the two Oconee spent fuel pools be decayed a minimum of 43 days prior to spent fuel cask movement.
Discussion By letter dated July 22, 1974, we requested that the licensee furnish, as 7j..
an amendment to the Oconee FSAR, additional information on the Ocenee facility design and coerating procedures related to scent fuel handling that demonstrates that the objective of Section 50.34(b)(4) of 10 CFR 50 is met, or will be met by appropriate plant modificaticns.
Section 50.34 F"
(b)(4) requires that analysis and evaluation of the design and perfornance of structures, systems and ccmconents of the facility with the cbjective of assessing the risk to public health and safety, in particular, including
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determination of the adacuacy of structures, systems and ccmponents provided fc the prevention of accidents and mitigation of the consequences of accidents, be included in the FSAR.
Revision 35 to the Oconee FSAR, issued by the licensee en September 30, 1974, included a description of the equipment used to hancle spent fuel casks at the Oconee Nuclear Staticn.
By letter dated August 29, 1975, we advised the licensee that revision 35 did 7t contain sufficient analysis to
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support its conclusions on spent fuel cask handlina system acceotability.
We therefore recuested that the licensee provide additional information.
By letters datdd November 3,1975, March 19,1976 c.nd July 26, 1976, the
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licensee provided the additional information we requested.
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The licensee was requested to specifically address the possibility of a spent fuel cask dropping onto spent fuel stored in the pool and the b
resultant radiological consequences.
In additien, the licensee's submittal was to include the effects on the spent fuel pool liner should the spent fuel cask strike it during the postulated accident.
The licensee has conservatively estimcted that up to 76 fuel assemblies could be damcged should a failure of the spent fuel cask handling crane or other cask handling equipment occur.
In order to maintain the r
resultant whole body and thyroid doses well within the exoosure ouidelines C-of 10 CFR Part 100 it was d'etermined that all fuel assemblies in the spent W**
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fuel pool areas which would be vulnerable to impact from a postulated spent fuel handling cask accident should have previously been decayed for a minimum of 43 days. The licensee has therefore proposed that, prior to spent fuel cask movement, spent fuel stored in the first 13 rows of the Unit Nos.1 and 2 common scent fuel pool and in the first 20 rows of the Unit No. 3 spent fuel pool closest to the spent fuel cask handling area in each pool, shall be decayed a minimum of 43 days following its last activation in the reactor from which it was removed.
Evaluation p
Our review of the Oconee spent fuel handling system involved an evaluation of the consequences of a scent fuel cask tipping and falling cnto scent fuel assemblies in the spent fuel pool.
Th review included consideratien of both the safety and environmental aspects of such a postulated accident.
Safety Consideraticns As indicated by the licensee, the path of travel of the spent fuel cask handling crane does not allow the spent fuel cask to pass over stored fuel in either the pool cc.w to Units Nos.1 and 2 or in the Unit No. 3 pool.
7 However, assuming a failure of the crane or handling equicment, and that the falling cask strikes the rim of the scent fuel pool or cask platform in the pool, it can be postulated that the cask would be deflected onto
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the stored fuel closest to the cask handling area.
The licensee has considered the worst situation to be a-hoist cable failure when the cask is positioned over the fuel pool wall with a resultant eccentric drca of
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the cask onto the wall.
In such a case, the cask, as well as the ycke and load block of the cask handling system could be deflected onto spent fuel. The licensee provided an analysis of the failure postulated acove to determine the number of fuel assemblies which could be contacted.
The Oconee Unit No. 3 spent fuel pool was selected for the analysis since it v-will have a higher fuel storage density as a result of the license amendment issued by us on December 22, 1975, which authorized an increase in the fuel aseembly storage canccity from 216 to 474 assemblies.
The "J'
li~censee described the assumptions employed and conservatisms ccnsidered in its analysis and concluded that a maximum of 76 fuel assecolies could be affected in the postulated accident.
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Regarding the assumptions used by the licensee to detennine the resultant 1
radiation exposure doses from the postulated accident, we indicated to th_
licensee that a fuel radial peak:ng facter of 1.65 and a X/Q, value of
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2.2X10-4 sec/m3 (55 meterology at 1609 meters) would provide more con-servative estimates.
Using these value, exposure doses of less than 1 Rem Whole Body and 150 Rem Thyroid would be predicted if the 76 fuel cssemblies assumed to be damaged have first been allowed to decay a minimum of 43 days following reactor shutdcwn.
These conservative assumations and others we employed in our independent analysis of the spent fuel cask tip accident c2a and the resultant estimated doses are summarized in Toble 1.
Std In view of the above, the licensee has agreed to place technical specificaticn restrictions on the storage of fuel assemblies in both Oconee spent fuel pools to assure that scent fuel which might be contactec in a postulated dropped fuel cask accident has decayed for at least 43 days folicwing its last activaticn in the reactor from which it was removed.
The licensee also provided an analysis of the effects en the spent fuel pool liner should the cask strike it during this postulated accident.
It was indicated that the spent fuel pool concrete v.as originally designed
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for the cask drop accident.
Should the cask strike the bottom liner clate on the edge, however, localized concrete crushing of the fill concrete would occur and the liner olate would be ructured in the area of impact.
The licensee therefore analyzed this possibility to determine the rate that pool water would escace.
The results of this analysis shcw that the calculated leakage would be 21.3 gallons per day and would be well within the capacity of the pool water makeuo systems.
'!e have reviewed the licensees analysis and have concluded that the conditions assumed were ft.
appropriately conservative and agree that more than adequate makeup water
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would be available shculd damage to the spent fuel ecol liner occur.
mP-In summary, it is considered that the postulated dropped fuel cask accident
- =e evaluated herein is extremely remote.
Given a decoced fuel cask, it is highly unlikely that danage would occur to a significant numcer of stored spent fuel assemblies in either of the two Oconee s;ent fuel pccis due to the fact that the crane travel does not pass over stored fuel assemolies.
7 Nevertheless, we have determined that the analysis of the postulated dropped fuel cask accident submitted by the licensee uses ccnservative assumptions to obtain the maximum number of fuel assenblies affectec.
We have concluded that the assumptions and analytical techniques utilized are acceptable and that the licensee has adequately predicted the maximum number of fuel assemblies affected.
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Conclusion We have concluded, based on the considerations discussed above, that: (1) because the amendments do not involve a significant increase in the probability or consequences of accidents previously considered and do TIS not involve a significant decrease in a safety margin, the amendments do not i6volve a significant hazards consideration, (2) there is reasonaole assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be g
conducted in compliance with the Commission's regulations and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Am Environmental Imoact Aopraisal bb If, in a postulated fuel cask accident, the cask and associated handling device are assumed to tio and fall into the scent fuel cool and damage 76 fuel assemblies, the resulting thyroid and whole body doses would be well within the exoosure guidelines of 10 CFR Part 100 fo-5 per cent meteorology as discussed above, and would be <1 Rem to the thyroid for 50 per cent meteorology.
This is not significantly greater than the expected consequences of other accidents previously evaluated in the b,'"
Oconee Final Environmental Statement (FES).
Radioactive effluent releases from postulated fuel handling accidents remain unchanged from those p===
presented in the FES of March 1972. The realistic assumptions and estimated consequences for the spent fuel cask tip are summarized in Table 2.
In our Safety Evaluation supporting the license amendment issued on December 22, 1975, we indicated that the transfer of spent fuel frcm the Units Nos. I and 2 sj.
spent fuel pool to the Unit No. 3 spent fuel pool would possibly start in about
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4 years. The licensee has indicated to us that such transfers may actually r"--
commence in September 1976 following completion of the design modifications to the Unit No. 3 pool.
As concluded in our Environmental Imoact Acoraisal rs.
supporting the December 22, 1975 license amendcant, a maximum of about 150 spent fuel assemblies are excected to be transferred from the Units Nos.1 and 2 pool to the Unit No. 3 pool over the life of the clant.
The dose rate for F*'
the transfer of 150 assemblies was calculated to be apprnximately 150 man-rem.
This was considered not to involve a significant increase in the excectec occupational exposures as creviously reviewed.
We therefore conclude that the transfer of spent fuel assemblies between the two scent fuel cools earlier than previously expected is acceptable and should be allowed to proceed as I
is now planned.
0 With regard to possible contamination due to the maximum expected scent fuel pool leakage of 21.3 gallons per day due to a rupturec liner plate, the licensee provided information indicating that the nearest water source used by. the public that would become contaminated is Lake Hartwell (Xeowee River).
Based on permeability tests conducted at the Oconee facility, it would take a minimum of four years for any leakage to reacn
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the oil collection pond which is ultimately discharged to Lake Hartwell.
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5-This route is the most limiting of those examined.
We agree with the
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correct any damage to a spent fuel pool liner plate or to take other
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measures to prevent contamination of the Lake Hartwell water source.
Conclusion and Basis for Necative Declaration On the basis of the foregoing analysis, it is concluded that there will be no significant environmental impact attributable to the proposed action.
Having made this conclusion, the Commission has further concluded that no environmental impact statement for the proposed action need be prepared
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and that a negative declaration to this effect is appropriate.
Date:
September 10, 1976 s
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TAT.LE 1 i
CONSERVATIVE ASSUMPTIONS AND ESTE4ATED CONSEQUENCES
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FOR SPEST FUEL CASK TIP E('
AT OCONEE 3 2928 Mw:
Power level i--
3 years Operating time 1.65 Power peaking factor 43 days Decay ti=ee.
' Fraction in gaps:
30%
Kr-85 10%
All other noble gases
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10%
Iodine 76 Nu=ber of assemblies da= aged w
177 Nu._ber of asse=blies in core Iodine Decontamination Factor in pool water 100 Initial inventories at time of shutdown:
25,080 ci/Mw:
C'y
'r-131 259.5 ci/Mw:
Xc-131=
56,220 ci/Mvt Xe-133 410.2 ci/Mw:
7 Kr-85 3.47 x 10=3/see Breathing Rate F.
(43 days) _
Dose, re 5% X/Q, sec/=3 Thyroid
'n'nole Body EAB (1609 =)
2.2 x 10-4 150
<1 LPZ Ecundary (9656 =)
4.0 x 10-5 27
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REALISTIC ASSUMPTIONS AND ESTD!ATED CONSEQUENCES FOR SPENT FUEL CASK TIP AT OCONEE 3
~Power icvel 2928 Mwt
" k' Operating time 3 years Power peaklmg factor 1.0 Decay times 43 days u
Fraction in gaps:
Kr-85 20%
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All other nobic gases 2%
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Iodine 2%
A Number of assemblies da= aged 76 Number of assemblies in core 177
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Iodine Deconta=ination Factor in pool water 500
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Initial inventories at time of shutdown:
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I-131 25,080 ci/Mw y.
Xe-131m 259.5 ci/Mwt Xe-133 56,220 ci/Mwt Kr-85 410.2 ci/Mwt Breathing Rate 3.47 x 10-4 3
m /see Dose, rem (43 days) 50% X/0, see/c3 Thyroid
' hole Body
- EAB (1690 m) 4.7 x 10-5
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<1 LPZ Boundary (9656 =)
2.5 x 10-6
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