ML19241B730
| ML19241B730 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 05/29/1979 |
| From: | Donohew J, Zudans J Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19241B710 | List: |
| References | |
| NUDOCS 7907230361 | |
| Download: ML19241B730 (9) | |
Text
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION REFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter cf
)
)
COMMCN'AEALTH EDISCN CCMPANY
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Occket Nos. 50-295
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50-304 (Zion Station, Units 1 and 2)
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NRC STAFF TESTIMONY IN RESTONSE TO BOARD OUESTIONS 1(c), 4(d), and 4(f) by Jack Conchew John J. Zudans Question (4)(c):
What postulated accidents, which might affec'; the safety of plant personnel in the spent fuel storage building or which might result in the release of radiation or radioactive materials from the scent fuel storage building, vere scecifically analyzed in the FSAR, SER, ER and FES utilized in tre CP and CL li-censing reviews of Zicn Units 1 and 2?
Res:cnse:
The :cstulated accidents, which mignt affect the safety O clan c eratinc cerscnnel in the scent #uel stcrage buildinc or.eich micht result in the release o# radiation cr radioactive materials f-cm this buildinc, that were scecifically analyzed in the Final Safe y anal / sis Reccrt (CSAN, Sa#ety Evaluation Recert (SER), Environmental Recort (ER) or ~inal Environnental Statenent (FES) for Zicn Nuclear Ocwer Stati:n, Units 1 and 2 (Zion 1/2),
are given beicw:
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i
. FSAR:
Fuel Handlina Accident Earthquake, Tornado Missiles & Turbine Missiles SER:
Fuel Handling Accident Earthquake, Tornado Missil es & Turbine Missiles ER:
None FES:
Fuel Handling Accident Heavy Object Droo Onto Fuel Rack Ouestion 4(d):
Which, if any, of the postulated accidents in (c), above, will be increased in probability, magnitude or consecuence (to per-sonnel, to the general oublic or to the environment) if the proposed spent fuel pool modifications are carried out?
Resocnse:
Table 4.d-l lists the changes in the probability, magnitude or consequences and risks for the postulated accidents which affect the safety of plant operating personnel in the Scent Fuel Storage Buildina or result in the re-lease of radioactive material from this buildinc and which were analyzed in the Zion 1/2 FSAR, SER, ER or FES. These accidents are listed in the rescanse to Cuestion a(c).
The additional scent fuel wnicn wculd be stored in the cool due to the excan-sicn c' ccoi cacacity is tne oldest fuel which has act been shicced frcn Zion.
This fuel will have decayed several years. 'his fuel wot id make a negligible contribution to the magnitude or consecuences of accidents in the Scent uel Storage Building.
The only soert fuel which effectively contri-butes to the consecuences of accidents in the Scent Fuel Storage Building is ln C~G
,)
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. the last spent fuel to be placed in the pcol.
This is the spent fuel dis-charged during a refueling or a full core offload.
Yost of the gaseous fission products in irradiated fuel have short half-lives and decay to in-significant levels in a few months.
There will be spent fuel movements during the modification of the Zion 1/2 pool ecual to about 10 refuelings at Zion 1/2. This is for the ocol being modified af ter the scheduled 1980 refueling. This is an increase of 12.5%
over the number of refuelings expected at Zion 1/2 during its operating life-time. The spent fuel should have decayed at least one month in allowing the refueling to be coroleted before the mcdification of the cool is started:
therefore, the cotential concecuences for tne Fuel Handlinq Accident will be at least a factor of 10 lower than the values given in the Safety Evalua-tion (SE) dated October 1972 for Zion 1/2. Therefore, the risk from the Fuel Handling Accident to the oublic, the plant and the environment will be decreased during the modification of the coc i.
By letter tated 'lovem er 29, 1963, tne :cmmonwealtn Edison Comoany (the licensee) crovidec the project fiilestores schedule #or the Zion 1/2 #uel coc! mcdi#icaticn.
Basec on this letter, tnere shculd only be 532 scent fuel movements
'4.e., ecuivalent to 5 re#uelings: and tne scent fuel in tne Zion
'2 coci curing :ne pcol cci#ication will ce at learc cne year cit.
he 1;C sta## nas uncer way a generic review cf Icad hardlinq oceraticrs in the vicinity c# scent fuel cools to determine the likelihocd of a "eavy load imcacting fuel in the ccol and, 4# necessarv. the radiolccical conse-cuences of sucn an event.
Because Zicn 1/2 will be recuired to croh' bit
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loads greater than the nominal weight of a fuel assembly and handling tool to b3 transported over spent fuel in tne S:9, we have concluded that (1) the likelinced of a heavy load handling accident is sufficiently small that the proposed modification is acceptable and no additional restrictions on load handling operations in the vicinity of the SFP are necessary while cur review is under way and (2) there is no change in the probability, magnitude (to plant cersonnel, the public or the environment) or risk of an accident caused by dropoing a heavy load into the pool during the mcdification of the cool, The scent fuel shipoing cask will not be brought into the Scent Fuel Storace Building during the modification of the pool.
The scent fuel pit, the Auxiliary Building housing the spent fuel cit and the spent fuel pit cooling system are Class I seismic structures and ccm-ponents (rescense to FSAR Guestion 4.23).
The Auxiliary Building has been designed to withstand the impact of turbine and tornado-driven missiles (re-sponse to FSAR Guestion 10.3 and 15.2).
Therefore, the probability, mag-ritude or 0nsecuences, and risk for accidents resultinc fecm an earthcuake, tornado missiles cr turbine missiles are unchanged during the mccification of the 2007 A mal # unction or i:ss :f tre scent #uel oit : cling system is nct : nsicered an accident.
Tne :cnsecuence of sucn an event is addressec in the resconse ta Contention 2(c'
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. Tabl e 4.d-l CHANGE IN RISK FOR POSTULATIDN ACCIDENTS DURING SFP MODIFICATICN cc Ment Change FHA
- HODA*
CDA*
ETM the Following Probability increase none zero none (about 12.5")
Magnitude or decrease none none Consecuences (by a factor of about 10)
Risk decrease none zero none Fuel Handling Accident FHA
=
HCDA = Heavy Object Drop Accident Cask Crop Accident CCA
=
Eartncuake, Tornado Missiles a r.d EMT
=
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m
. Question 4(f):
Which, if any, of the postulated accidents in (c), above, will be increased in probability, magnitude or consecuence (to per-sonnel, to the general public or 00 the environment) as a re-sult of the completion of the proposed spent fuel pool modifi-cations and the proposed subsequent usage of toe increased spent fuel storage capacity?
Rasconse:
Table 4.f-l lists the changes in the probability, magnitude or consecuences and risks for the costulated accidents which affect the safety of plant personnel in the Spent Fuel Storage Building or result in the release of radioactive material from this building and which were analyzed in the Zion 1/2 FSAR, SER, ER or FES. These accidents are listed in the response to Question 4(c).
As discussed in the response to Question 4(d), the additional spent fuel in the pool because of the pool modification makes a negligible contribution tc the consecuences of accidents in tne Spent Fuel Storage Building.
There will not be a significant increase in the number of fuel handlir.g and shiocing cask movements because of the increase in cacacity cf the SFp. The total number of sniccing cask movements will decend on the size of the cask and tre numcer of asserblies to be snioced and not en the cacacity of the SFD.
Because *here are no recuirements in the specifications as to wnere the freshly discharged scent fuel must be stored, the numoer cf fuel handling mcvements should not change because of the increase in tne SFO cacacity.
Therefore, the modific. tion of tne cool does not chance One orc:aci~ ity of the Fuel Handling accident and the Cask Droo Accident.
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The scenario for the postulated fuel handling accident is the dropping of a fuel assembly directly onto another assembly in the spent fuel pool resulting in the rupture of all of the pins in the equivalent of one assembly.
SMce this scanario is the most severe fuel handling accident and results in the most conscrvative analysis, the increased fuel density in the cool would not increase the consecuences of this accident and further analysis is n;t needed.
In addition, operating exoerience to date nas indicated that no apare:iable radiological eleases can be expected fron a fuel handling accident.
The NRC staff has not completed its review and evaluation of the potential rac,ological consecuences of a spent fuel shipoina cask falling into the Zion 1/2 pool. Until this review is completed, a shipping cask will not be allowed near the pool.
If a shipping cask fell into the pool, the additional scent fuel in the pool because of the proposed pool modification may increase the consequences of this accident to the olant personnel, the public and to the environment; however, this increase would not be sis. ificant. The addi-tional fuel in the cool because of the pro?osed pcol modification will have decayed several years. This decay will reduce the radioactivity cf volatile and gaseous material to negligible levels so that inis additional fuel is not imoortant in calculating tne cotential consecuences of this accideqt.
Tqe EC staf# has und, r way a generic review o# load handling coerations in tne vicinity of scent #uel ocols to determine the li'<elinocd of a heavy load impacting fuel in tne cool and, if necessary, the radiclogical consecuences of such an event. Because Zicn 1/2 will be recuired to orchibit loads greater than the ncminal weiant of a fuel assemoly and har2inc tool to be transcorted C '.. \\.
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over spent fuel in the SFP, we have concluded that (1) the like:ihood of a heavy load handling accident is sufficiently small that the propo;ed mcdifica-tion is acceptable and no additional restrictions on load handlina operations in the vicinity of the SFP are necessary while our review is under way and (2) there is no change in the probability, magnitude (to plant personnel, the public or the environment) or risk of an accident caused by droopino a heavy load into the pool af ter completion of the :odification of the pool.
The spent fuel pit, the Auxiliary Building housina the '. cent fuel pit and the spent fuel pit cooling system are Class I seismic structures and comoonents (rtsconse to FSAR nuestion 4.23).
The Auxiliary Buildina has been designed to withstand the imcact of turbine and tornado-driven missiles (.rescanse to FSAR Ouestion 10.8 and 15.2). Therefore, the probability, magnitude or consecuences, and risk fcr accidents resulting fran an earthcuake, tornado missiles or turbine missiles are unchanced after ccrpletion of the modifica-tion of the pool, a malfunction or loss of the spent fuel ait cooling system is not considered an accider..
The consecue.;ce of such an even: is addressed in the resconse to Ccntention 2';).
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Table 4.f-l CHANGE IN RISK FOR POSTULATED ACCIDENTS AFTER SFP MODIFICATION Change Accident I"
- HCDA*
CDA*
ETM the Following Probability none none none none Magnitude or none none insignificant ncne Consequences increase Risk none none insicnificant none increase
- FHA Fuel Handling Accident
=
HCCA = Heavy Cbject Drco Accident Cask Drop Accident CCA ET'!
Eartnquake, Tornado Missiles and
=
/3 L C..$