ML20213G054
| ML20213G054 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 10/29/1986 |
| From: | Hunsader S COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 2338K, NUDOCS 8611170302 | |
| Download: ML20213G054 (4) | |
Text
5 co s
?. c), One First Natknej Plaza. Chicago, Illinois
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/ Address Reply to: Post Offes Box 767 y
L/ Chicago, Illinois 60690 - 0767
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October 29, 1986 s:
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Mr. Harold R. Denton i
Office of Nuclear Reactor Regulation 1 U.S.
Nuclear Regulatory Commission N
Washington, DC. 20555 8
3, N
Subject:
. Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Final Safety Analysis Report Revicions NRC Docket Noc. '30-4 54 /455 and 50-45C /4 57
Dear Mr. Denton:
This,'sletter provides' adirance'information of changes to be made to the l'y' con /Braidwood FSAR that 'are to be includedCin the nsxt Amendment submittal.
There advance copies are provided to allow for early NRC review.
'N Attachment A includes the affected Byron /Braidwood FSAR, pages 9.1-9a and 9.~1-29 with the indi:ated changes marked as to i
where they are to be inserted.
Attachment B provides the wording additions dealing with dry storage bf new fuel in'; t he l u pent fuel..
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racks ands f uel assembly -edge to edge. distances. ' '
Should you have any questions, please contact this office.
o p e signed original and' fifteen copies o'f this letter and l
the attachments are provided for your review.
4 Very truly yours, t
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S.C. Hunsader Nuclear Licensing Administrator
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cc:
L. Olshan J.
Stevens att.
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P611170302 861029 PDR ADOCK 05000454 P
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ATTACHMENT A B/B-PSAR AMEND!iENT 38 MAY 1982 O
L The results show a nominal k,,, well below 0.762.
Thus, the I
worst accident case as analyzed, does not have consequence any more than the worst normal distribution case.
Dev Storage of New Fuel in Spent Tuel Racks The design of the spent fuel storage racks also allows a subcritical effective multiplication factor for dry storage of new fuel with 3.20 w/o enrichment in a checkerboard loading pattern: k less than 0.98 for the optimum moderation condition 3$a,k
, less than 0.95 for the flooded condition inaccordancewTkhANSIN210-1976.
Under the checkerboard loading pattern, new fuel assemblies are to be placed in rack positions with four nearest adjacent positions empty.
The optimum moderation condition exists when the storage racks are covered with clean water at a uniform density of 0.05 gm/cc.
The flooded condition exists when the storage racks are covered with cold, clean, unborated water at a full density. (INSERT)
The criticality analysen of these two conditions were performed with the assumptions and calculational methods similar to those utilized for the analyses of new fuel racks in Subsection 9.1.1.3.
The only exception was that the spent fuel storage rack was assumed to be infinite in size in all three dimensions O
for additional conservatism.
Under the optimum moderation condition of 0.05 gm cc water for the spent fuel racks containing the 3.20 w/o enrichment fuel in the checkerboard loading pattern, the k as deter-mined is 0.8904.
Adding reactivity ef fects of 8$kculational uncertainties of 0.0153 ak and geometric and material uncer-tainties of 0.0479 ak to the optimum moderation k*$k a 95%
results in a maximum k of 0.954 with a 95% probability confidence lev,[,, which satisfies the design basis of main-e taining k below the design-basis limit of 0.98.
eff When the spent fuel racks containing the 3.20 w/o enrichment fuel in the checkerboard loading pattern are flooded with cold, unborated water, the nominal k,, is 0.8413.
Adding reactivity effects of calculation un,ettainties of 0.0198 ak, c
geometric and material uncertainties of 0.0056 ok, and the temperature decrease effect (from 68* F to 40* F) of 0.0014 Sk to the nominal k results in a maximum k of 0.868 with a 95% probabTk,ityat a 95% confidence Te,0el, which satisfies the design basis of maintaining k below eff the design-basis linit of 0.95.
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9.1-9a
f ammacuMFNT A
~ 75-F5AR AMENDMENT 43 E
5 SEPTEMBER 1983 i
The f uel handling equipment is designed to handle a spent fuel assembly underwater f rom the time it leaves the reactor vessel until it is ready for placement in a container ror shipment from the site.
Underwater transrer of spent fuel assemolles provides an effective, economic, and transparent radiation shield, as well as a reliaole cooling medium for removal of decay heat.
The i
boric acid concentration in the water is sufficient to preclude criticality.
Ihe associated fuel handling structures may be generally divided into two areas:
the refueling cavity and ref ueling canal which are floodeo only during plant shutdown for refueling, and the I
i spent rerueling cavity, which is xept f ull or water and is always j
accessiale to operating personnel.
Tne refueling canal and the j
l rerueling cavity are connected by a fuel transfer tube.
This l
tuae is ritted witn a gate valve on the fuel storage area end.
ruel is carried through the tuce on an underwater transfer car.
Fuel is moved cetween the reactor vessel and the refueling canal l
by the refueling macnine.
The PCC Change Fixture is used for transrerring control elements f rom one fuel assembly to another a
i fuel assemoly.
The FTS is used to move ruel assemolies between j
the containment ouilding and tne fuel storage builaing.
Arter a l
1 ruel assemoly is placed in the fuel container, the lif ting arm l
eivots the tuel assemoly to the horizontal position for passage i
tnrough the fuel transf er tune.
After the transfer car transports tne ruel assemoly through the transfer tube, the i
lif ting a rm a t that end of the tune pivots the assembly to a i
vertical position so that the assemoly can be lifted out of the fuel container.
In the fuel storage building, fuel assemblies are moved about by i
j the spent fuel pit bridge crane and the fuel handling building crane.
When lifting fuel assemblies with the spent fuel pit bridge crane,
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the hoist uses a long-handled tool to assure that sufficient radiation shielding is maintained.
A shorter tool is used with the fuel handling building crane to handle new fuel assemblies initially, and for operations following receipt of assemblies for initial core loading, the new fuel elevator must be used to lower the l
assembly to a depth at which the spent fuel pit bridge crane, using the icng-har.dled tool, can place the new fuel assemblies into or out of the fuel storage racks.
l (INSERT) 9.1.4.2.1 Refuelina Procedure t
Ihe refueling operation follows a detailed procedure which i
provides a safe, ef ficient refueling oteration.
Prior to initiating refueling operations, tne reactor ccolant system is i
l borated and cooled down to refueling shutdown conditions as sCecified in the technical specifications.
Criticality protection :or refueling cperations, including a requirement for daily enecks of boron concentratians, is specified in the technical specifications.
The following significant points are assured by the rerueling procedure:
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l 3.1-29 1
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ATTACHMENT B l
1)
Pace 9.1-9a.
insert following 1st paragraph as indicated:
"Until the spent fuel pool is filled with water fuel assemblies shall be stored in such a manner that water would drain freely i
froc the assemblies in the event of flooding and subsequent draining of the fuel storage area.
In addition, two fuel assemblies may be placed in two water-filled failed fuel containers (on 44-inch centers) for primary neutron source installation and shielded storage provided that the water has a boron concentration of at least 2,000 ppm.
The failed fuel container between the two fuel assemblies shall also be filled
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with water having a boron concentration of at least 2,000 ppm."
2)
Page 9.1-29, insert prior to Sec. 9.1.4.2.1:
"As a precaution to prevent an inadvertent criticality while transferring new fuel between the new fuel storage vault, spent fuel storage pool, and the reactor vessel wnile the spent fuel pool is in a dry condition, the minimum edge to edge distance of twelve (12) inches shall be maintained between a fuel assembly l
outside its shipping container, the storage racks or the reactor vessel and all other fuel assemblies.
More than two fuel 1
assemblies may be out of their shipping containers, storage locations or the reactor vessel provided the twelve inch minimum t
edge to edge distance is maintained in addition to insuring that i
a minimum separation distance of five (5) feet is maintained l
l between groups of assemblies in motion."
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