ML20210U414
| ML20210U414 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 02/12/1987 |
| From: | Kowalski S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Butler W Office of Nuclear Reactor Regulation |
| References | |
| CON-#187-2529 OL, NUDOCS 8702180473 | |
| Download: ML20210U414 (7) | |
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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 (215)841-4502 S. J. KOWALSKI VIC E-P R ESID E N T ensenesnine ano massamen Mr. Walter R.
Butler, Director FEB 12 567 BWR Project Directorate #4 Division of Licensing U.S.
Nuclear Regulatory. Commission Washington, DC 20555 Docket No.:
50-353
Subject:
Limerick Generating Station, Unit 2 Charcoal Filter Cooldown Mode for Reactor Enclosure Recirculation System i
References:
1.
Le tter f rom S.
J.
Kowalski (PECo) to W.-R.
Butler (NRC), dated December 29, 1986 2.
Telecon between PECO, NRC and Bechtel on January 16, 1987.
File:
GOVT l-1 (NRC)
Dear Mr. Butler:
Philadelphia Electric Company proposed to make changes to the design and operation of the Reactor Enclosure Recirculation System (RERS) for Limerick Generating Station Unit 2 in the reference letter.
In support of the proposed changes, the.results of calculations performed to' quantify the potential radioactive decay heat buildup in the RERS charcoal adsorbers were also provided in the reference letter.
L l
A request for additional information was received via the reference telephone call.
In the call, Messrs.
R.
E.
Martin and J. Lee of the NRC asked -that PECo provide additional information regarding specific parameters and general methodology used in the above mentioned calculations.
The requested information is provided in.the attachment.
As indicated in the reference letter, we request your decision on the proposed changes to the RERS by April 1987.
l 8702180473 B70212 (d
ADOCK05000gg3 PDR A
- w -
W
.. If we can be of further assistance in this matter _,
please contact us.
~~-
Sincerely,
- ffS,
- ar
^ 5 S.J.
Kowalski Vice Presidenti Engineerin and Research Attachment cc:
Troy B.
Conner, Jr. Esq.
(w/ attachment)
Benjamin' H.
Vogler, Esq.
(w/ attachment)
Mr. Frank R.
Romano (w/ attachment)
Mr. Robert L. Anthony (w/ attachment)
Ms. Maureen Mulligan (w/ attachment)
Charles W.
Elliot, Esq.
(w/ attachment)
Barry M.
Hartman, Esq.
(w/ attachment)
Mr. Thomas Gerusky f(w/a ttachmen t)'
i Director, Penna Emergency (w/ attachment)
Management Agency Angus R.
Lo ve, Esq.
(w/ attachment)
David Wersan, Esq.
(w/ attachment)
Robert J.
Sugarman, Esq.
-(w/ attachment)
Kathryn S.
Lewi s, Esq.
(w/ attachment)
Spensce W.
Perry, Esq.
(w/ attachment)
Jay M.
Gutierrez, Esq.
_ (w/ attachment)
Atomic Safety & Licensing (w/ attachment)'
Appeal Board Atomic Safety & Licensing (w/attachmemt) -
i; Board Panel Docket & Service Section
'(w/ attachment)~.
Mr.
E.
M.
Kelly
( w/a ttac.hment)
Mr. Timothy R.
S.
Champbell (w/ attachment):
i 3:
BCG/sw/01208702 4
,y
+e.
ye
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ATTACHMENT q7 Limerick Generating Station, Unit 2 Charcoal Filter Cool. Down - Mode ~ Deletion For Reactor Enclosure Recirculation Syspfqm a
Letter From:
S.
J.
Kowalski (PECo)-
To:
W.
R. Butler (NRC)
DESCRIFTION OF LOCADOSE MODEL USED In the RERS cooldown analysis, the activities in,the RERS-charcoalifilters were calculated using Bechtel Standard Computer program LOCADOSE NE319 Rev.
2.
A five-region model (see Figure 1) was used in the LOCADOSE runs with the environment as Node 1, Pr)1 mary Containment as Node 2, Reactor Building as Node 3, Suppression Pool as Node 4, and RERS filter as Node 5.
Regulatory Guide 1.3 iodine source term-for a DBA LOCA consisting of 25% of the core iodine inventory was used as the initial activity airborne inside the primary contafnment available for ' release.
Further, it was conservatively assumed that 50% of thetcore iodine inventory was in the suppression poql water.
The airborne activity inside the primary containment is assumed to leak to the reactor building at a rate of 0.5% per day with an 7 additional 11.5 scfh leakage per Main Steam Isolation Valve (MSIV).
Also, an equipment leakage of 5 gpn of suppression pool water is conservatively assumed to leak into.the reactor building.-
1 A decontamination fabtor of 10 was assumed to determine the fraction of iodine activity becoming airborne from' the' equipment leakage.
The airborne activity 'in the reactor building. is then accumulated in the Reactor Enclosure Recirculation System (RERS).
at 60,000 cfm.
A mixing ef ficiency.of 50% was ass,umed within the reactor enclosure (secondary containment).
To mapimize the' activity loading on thq RERS. filters, the foIlowing: assumptions were used:
'4 14 no unfilte red leakage to the environment during the 2 minutes 15 seconds drawdown time:
2'4 no credit for iodine removal mec'hanisms; 100%charcoalfilterefficiencyforthhRERSfilters.
N 3.
5 h
Page 1 of 5 h:n~_
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s DESCRIPTION OF_FILTLOAD MODEL USED The Bechtel computer program NE299 FILTLOAD calculates the mass loading in grams and the heat loading in watts using the activities generated from TOCADOSE NE319.
The heat loadings are calculated conservatively assuming 100% of the beta energies and 50% of the gamma energies for each isotope are adsorbed in the filter.
The remaining 50% of the gamma energies were assumed lost.
Heat losses from the charcoal filters due to natural con-vection and radiation were considered in the RERS cooldown analysis.
The surface area for convective heat transfer was taken as the face area of the front of the filter and the surface area for radiative heat transfer was taken as the outside steel surface area.
The convective heat transfer coefficient used in the program FILTLOAD 1s the empirical constant for natural convection 2
(0.221 Btu /hr-ft R) taken from ORNL-4602.
No heat loss due to cooling from air flow through the charcoal filters was considered once maximum activity loading on the filters was attained.
The temperature rise was then calculated by subtracting the heat loss from the heat loading due to radioactive decay.
FILTLOAD does not calculate heat loading due to oxidation since the contribution is small.
It is estimated that at the maximum heat load (at 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br />), the oxidation heat load is approximately 42 watts, 3% of the decay heat load.
The decay heat load from noble gases heldup in the RERS filters was not calculated but was estimated to be no greater than the oxidation heat load.
Page 2 of 5
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TABLE 1 LIST OF PARAMETERS
]
_P_ARAMETERS USED VALUE Thermal Power Level - 105%
3458 MWT Volumes in cubic feet Primary Containment 397,466 Secondary Containment 1,800,000 Suppression Pool Water 128,360 Containment leak rate 0.5% / day or 1.3801 cfm RERS Flow in cfm 60,000 MSIV leakage (11.5 scfh'*4 loops) 46 scfh Secondary Containment mixing efficiency 50%
ECCS leakage in cfm 0.668 RERS Fflter Data Charcoal Mass 13,000 lbs or 5896.67 kg Temperature of air rJow 150 deg F Depth of charcoal bod 2 inches Surface Area for natural convection 1,520 sq. ft Surface Area Ignition'4diation for r 820 sq. ft Charcoal temperature 626 deg F Emissivity of casing (steel) 0.80 Temperature of Environment for radiation heat transfer 150 deg F Page 3 of 5
TABLE 2 Activity, Mass, and Heat Loads on the RERS Filters NO COOLING AIR Temperature Time Activity Mass Heat Rise (hrs)
(Curies)
(grams)
(Watts)
(Deg-C) 0.00E40 0.000E40 0.000E40 0.000E40 0.000E40 2.50E-1 5.266E+3 1.916E-1 4.131E+1 6.586E-2 5.00E-1 1.522E+4 5.911E-1 1.160E+2 1.754E-1 7.50E-1 2.586E+4 1.067E+0 1.917E+2 2.813E-1 1.00E+0 3.604E+4 1.571E+0 2.598E+2 3.736E-1 2.00E+0 6.990E+4 3.640E+0 4.555E+2 6.279E-1 3.00E+0 9.643E+4 5.716E+0 5.778E+2 7.815E-1 4.00E40 1.190E+5 7.790E+0 6.661E+2 8.902E-1 5.00E+0 1.389E+5 9.862E+0 7.358E+2 9.751E-1 6.00E+0 1.569E+5 1.193E+1 7.935E+2 1.045E+0 7.00E+0 1.732E+5 1.400E+1 8.424E+2 1.103E+0 8.00E+0 1.881E+5 1.607E+1 8.843E+2 1.153E+0 9.00E+0 2.018E+5 1.813E+1 9.207E+2 1.196E+0 1.00E+1 2.143E+5 2.019E+1 9.526E+2 1.233E+0 1.20E+1 2.368E+5 2.432E+1 1.005E+3 1.295E40 1.40E+1 2.562E+5 2.843E+1 1.047E+3 1.344E40 1.80E+1 2.881E+5 3.665E+1 1.107E+3 1.413E+0 2.40E+1 3.242C+5 4.894E+1 1.158E+3 1.470E40 3.60E+1 3.728E+5 7.341E+1 1.194E+3 1.513E+0 4.80E+1 4.057E+5 9.774E+1 1.200E+3 1.519E+0 6.00E+1 4.313E+5 1.220E+2 1.196E+3 1.515E+0 7.20E+1 4.533E+5 1.461E+2 1.192E+3 1.511E+0 8.40E+1 4.737E+5 1.701E+2 1.193E+3 1.512E+0 9.60E+1 4.933E+5 1.939E+2 1.201E+3 1.520E+0 1.20E+2 5.309E+5 2.414E+2 1.233E+3 1.557E+0 2.40E+2 6.404E+5 4.733E+2 1.411E+3 1.759E+0 3.60E+2 6.141E+5 6.970E+2 1.351E+3 1.691E+0 4.80E+2 5.243E+5 9.134E+2 1.153E+3 1.466E+0 6.00E+2 4.197E+5 1.123E+3 9.234E+2 1.199E+0 7.20E+2 3.225E+5 1.327E+3 7.096E+2 9.433E-1 9.50E+2 1.764E+5 1.716E+3 3.881E+2 5.420E-1 1.20E+3 9.048E+4 2.083E+3 1.991E+2 2.914E-1 2.40E+3 2.115E+3 3.622E+3 4.653E+0 7.978E-3 3.00E+3 2.872E+2 4.234E+3 6.306E-1 1.121E-3 3.60E+3 3.801E+1 4.761E+3 8.234E-2 1.494E-4 4.08E+3 7.886E40 5.129E+3 1.597E-2 2.923E-5 4.32E+3 3.862E+0 5.297E+3 7.072E-3 1.298E-5 Page 4 of 5
FIGURE 1 - LOCADOSE REGION MODEL FOR THE RERS FILTER 3
MSIV-LCS (4 vdies @ 11.5 scfh)
RERS Reactor BuRding Filter g
(Node 3)
(Node 5) 5 0.6 %/ day 25% Core lodines Containment (Node 2) 60% Core locAnes Suppression Pool 10 (Node 4) l 1
Node 1 - ErMronment l
Page 5 of 5
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