ML20215L925
| ML20215L925 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 10/10/1986 |
| From: | COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20215L916 | List: |
| References | |
| NUDOCS 8610290369 | |
| Download: ML20215L925 (4) | |
Text
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Figuro 3.2-9 Hot Channel Factor Normalizcd Oparating Envelope for Units 1 and 2 F
Constant (Loca Limiting Value) = 2.32 g
i i
(0.0,1.000) ;
(6.0, 1.000) i (10.8, 0.940)
- 1. 0 -
N i
4
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f
- 6 (12.0, 0.612) n e=
w g
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E u
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2 1
i ea
{
~
x i
2 4
6 8
10 12 l
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Core Height (feet)
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-63a-8610290369 861010 PDR ADOCK 05000295 P
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ATTACHMENT 2 DEVELOPMENT OF K(z) AT THE 12' LEVEL REFERENCES (1): Reload Safety Evaluation for Zion Nuclear Power Plant Unit 1, Cycle 2 dated November 1975.
(2): CECO Response to NRC Request for Additional Information, G.L. Pliml to R.A. Purple dated April 19, 1976.
(3): NRC/SER dated May 12, 1976 Supporting Amendment Nos.
20/17 to Facility Operating Licenses DPR-39 and 48 (4): Westinghouse Letter 82CW*-G-080, J.M. Corkle to H.E. Bliss dated May 21, 1982; Subject "K(z)
LOCA Envelope for Zion".
This report tracks the acceptance and use of a 1.42 "Fq x P" value for Zion fuel at the 12' level for the Small Break Loss-of-Coolant Accident (SBLOCA) line of the Hot Channel Factor Operating envelope, and supports the correction of the recent error discovered in Zion Technical Specification K(z) curve, Figure 3.2-9.
The SBLOCA was reanalyzed for Zion Unit 1 Cycle 2 to accomodate an increase in the LOCA K(z) envlope third line segment from (12', 0.44) to (12', 0.63) for a maximum Fq at rated power of 2.25 (Reference (1)). The K(z) values are normalized Fq(z) values for the " Heat Flux Hot Channel Factor Normalized Operating Envelope".
In order to calculate K(z) at the 12' level, you would take the Fq(12') and divide by the maximum Fq.
As the K(z) value, not the actual Fq value, was reported for the 12' level in the Zion Unit 1 Cycle 2 RSE, as 12' Fq would be back calculated as such:
K(z) = Fq(z) / max Fq
@l2':
0.63 = Fq(12') / 2.25
===)>
Fq(12') = 1.4175 The Reference (1) RSE was submitted to the NRC and, as part of their review, CECO was requested to provide additional SBLOCA information.
The additional information requested by the NRC was provided in Reference (2). Reference (3), in part, provided NRC approval for a Zion Unit 1 Cycle 2 revised K(z) third line segment.
In none of the first 3 references was the actual 12' level Fq value of 1.42 reported, only the K(z) value. As these documents were issued in the mid-1970's, the appropriate pages are included to aid in the review.
. Technical Specifications require normalized Fq values for the K(z) curve but the SBLOCA analysis is performed using the un-normalized Fq value. The 1975 SBLOCA analysis had an actual Fq of 1.42 (Reference (4))
but it is standard practice to report a K(z) value that is normalized to the max Fq and then rounded down to two decimal places. As such, the value for the 12' K(z) is 0.6311+ but was reported as 0.63.
It was because CECO had conservatively calculated the 12' Fq as 1.4175 (see above) that Westinghouse issued the Reference (4) letter (attached), and it was that reference for which an internal file seach showed that the SBLOCA 12' operating envelope endpoint first appeared as a 1.42 Fq, not the-rounded 0.63 K(z) or its back calculated Fq equivalent.
Thus, the current, correct value of K(z) at the 12' level is simply obtained by:
1.42 = 0.612 2.32 2038K
3ica Rs6
.~
3.0 POWER CAPABILfTY AND ACCIDENT EVALUATION 3.1 Pgwer_Cagabili}y' The olant ocwer caoability is evaluated (considering the consecuencas of -hose., incidents examined in tne FSAR
'l and fuel densification repo rts " #, using'the previously accepted design basis.
It is concluded that the ccre reload will not adversely affect the ability to safely noe' rate at 100% of rated power during Cycle 2.
For the overpower transient,' a maximum local rod power limit of 22.6 kw/f t corresponds to the burnup dependent fuel centerline temperature limit of 4700 F.
This can be accamodated with The time dependent densification modelggin in the Cycle 2 core.
was used for this evaluation.
The LOCA limit at rated power is met by maintaininci F at or belcw 2.25 depending on core height, as shown in Figure g
2.
This curve is satisfied by the power control maneuvers allowed ay the Technical Soecifications, which assure that the FAC criteria are met for a caectrum of small and large LOCAs.
The small break l')CA was reanalyzed for Cvela '/
- a accomodate an increase in tne P z) tniro line coordinate (Figure 2) from (12.0, 0.44) to (12.0, 0.53)*
3.2 egidegg,[yalua}{gg The effects of the reload on the design basis and postulated incidents analyzed in the FSAR have been examined.
In most cases it was found that the effects can be accomodated within the conservatism of the initial assumptions used in the previous applicable safety j
analysis.
For those incidents which were analyzed, it was determined that the aaplicable design basis limits are not exceeded, and therefore, the conclusions presented in the FSAR and densification reports are still valid.
A core reload can typically affect accident analysis input parameters i
l in three major areas:
kinetics characteristics, control rod worths, and core peaking factors. Cycle 2 parameters in each of these tnrae areas were examined as discussed below to ascertain whether anw &cident annlyses were required.
Xinetics Parameters - A comparison of Cycle 2 kinetics parameters witn tne current limits is given in Table 2.
The Doppler power coefficient and prompt neutron lifetime are within the bounds of the current limit. Table 2 shows that the Cycle 2 moderator density coefficient exceeds the current limit by.003 a k/gm/cc; however, this change is not significant.
For a cooldown transient which results in a 10 F decrease in reactor coolant temperature'(aporoxinately
.31 gm/cc increase in moderator density) for example, the increase in reactivity due to the change in moderator coefficient is only YIoad ECC5 analysis, Zion Nuclear Plant Unit 1, Cycle 2.
To be supplied later under separate cover. h
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