ML20065C759
| ML20065C759 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/17/1982 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 5211-82-223, NUDOCS 8209240298 | |
| Download: ML20065C759 (7) | |
Text
.
GPU Nuclear Corporation 5 U tuclear m' age 8s48o S
Middletown. Pennsylvania 17057 117 944-7621 TELEX 84-2386 Writer's Direct Dial Number:
September 17, 1982 5211-82-223 Office of Nuclear Reactor Regulation Attn:
J. F. Stolz, Chief Operating Reactors Branch No. 4 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 TMI-l Containment Flood Level Calculation In response to your request for additional information dated July 26, 1982, enclosed please find information concerning the subject item which supple-ments our response of June 11, 1982.
S
- erely,
'i l
11
. Ilukill Director, TMI-l 11D11: LWil: CJS : vj f l
Enclosure cc:
R. Jacobs j
R. C. Ilaynes lODl l
l k9 98 820717 P
K 03000289 PDR GPU Nuclear Corporation is a subsidiary of the General Pubhc Utilities Corporation
TMI-1 Containment Flood Level Calculations Item 1:
In the containmenc flood level calculation the volumes of the major structures in containment are calculated based on what appears to be the design value dimensions. Verify that no significant differences exist between actual plant dimensions and design dimensions.
Include in your reponse tolerances for wall dimensions and thicknesses, and values and tolerances for floor slope.
Discuss the effects of the tolerances and slope on the conservatism of the flood level calculations.
Response
In the calculations nominal dimensions were used.
This approach is conservative for the following reasons:
As indicated in the FSAR (pas 5-331 erection tolerance for RB liner is + 3 in.
As the plates are installed during construction and tend to go out of tolerance, the next plate is brought back to tolerance.
The tolerance variation could as likely increase available'floodable volume and reduce the flood level.
The net effect of any tolerance variation is believed to be zero and was not included due to other conservatisms that were included as discussed below.
In our calculation conservatism has been built in by assuming the RV cavity and the stairway as not being floodable, the trench as being solid (also not floodable) and the sump full.
3 Elevator shaft -
99 ft. /ft.
RV cavity
- 855 f 6j / f t.
- 1170 ft. /ft.
Trench
- 450 ft.
l However, recalculating the available volume using the FSAR worst tolerances with the exception of the RCDT compartment, elevator shaft and letdown cubicle wall which have been scaled off the drawings, yields a maximum water level to be 5.73 feet.
Based on the above, it can be seen that this additional conservatism I
is unnecessary, but even if it were to be introduced, the maximum permissible water level of 5.81 feet is not reached.
l Item 2
{
j Several non-floodable structures in the floor region of containment have been neglected in the flood level calculation, specifically, the steam generator supports, ventilation equipment supports, stairways, and grating support columns.
Consider the contribution of these and any other unaccounted structure and equipment, and revise the flood level calculation as appropriate.
Response
The above were evaluated and found to have insignificant effect on the overall calculations when compared to the conservatism indicated in 1 above., For example the larg accountforlessthan4.8ft.gstsupports,thesteamgeneratorsupports,
/ft.
Therefore, we consider the above stated conservatism to be far in excess to cover the items neglected.
Jtem 3 In determining the volume of water added to containment, a portion of the BWST and NaOH tank contents is assumed to remain in the tanks.
Provide sketches an calculations to support this assumption.
- Also, address the significance of water addition from the coolant storage makeup tank during a small break LOCA.
Response
The maximum available volumes for both the BWST and NaOH tanks are from the limits and precautions procedures (OP 1101-J)
For your information, the BWST discharge piping (24") is 2'4" above the tank bottom, and the NaOH discharge (4") is 2'6" above tank bottom (See attached pages from OP 1101-1).
With regard to make-up tank additions, it should be noted that the tank is isolated on HPI initiation. Therefore, it is not appropriate to include this in the RB flooding calculation. However, the MU-T volume (507 ft.) if included would not increase the calculated water level significantly (5.71' vs. 5.66').
It should be noted that this level assumes the makeup tank to be full to its maximum usable volume and that all the volume is injected into the RCS. Normally, this tank is only 73% full.
Item 4:
With regard to the leakage of service water into containment, provide summary description of a) all service water systems expected to be a
operational following onset of a LOCA, including emergency fan coolers; b) leakage experience for these systems (including typical leakage rates ; c) surveillance procedures and operating limits for these systems; d) leak detection and isolation provisions for each system; and e) containment flood level monitoring instrumentation (including location, range, indicators, and alarms).
r-r-
Response
a) Service Water Systems inside RB:
(a) RB Emergency Cooling System or Nuclear Service Closed Cooling System (b) Main Steam System (c) Feedwater or Emergency Feedwater Systems
- (d) Fire Service System
- (e) Nuclear Service Closed Cooling System (RC Pumps)
- (g) Liquid Waste disposal (RCDT to Isolation Valve &
- (h) Demineralized Water (Isolation on Reactor Trip)
- Isolated by RB isolation system b) While no exact data ls available from these systems, the leakage into the sump is considered minimal.
Discussion with Operations Department indicate that leakage into the sump is less than 1,000 gallons per month.
Additionally, the RB emergency cooling system has a flow rotometer installed and is checked daily as part of the plant surveillance and provides assurance that the system is not leaking (RB emergency cooling is not normally used and prior to the event.
any leakage would be noticed on the flow rotometer.)
(c/d) There are no specific surveillance, operating limits, leak detection or isolation provisios on these systems.
There are, however, feedwater and emergency feedwater flow indications to the steam generators.
There are also surge tanks in various closed cooling systems which have a low level indication / alarm which when investigated would indicate leakage.
e) Safety grade, redundant Reactor Building and Reactor Building Sump level transmitters are installed with an accuracy of + 1/2" (Lt 804, 805, 806, and 807).
All instruments have a range of ~0-90" (0-7'-6").
The alarm points for these instruments have been arbitrarily set at
i Item 5:
r The TMI-1 flood level calculation yields a " reactor building floodable 4
volume per foot of height" of 10,771 f t.3/ft.
The value of TMI-2 is quoted to be 6000 gal./in. or 9,626 f t.3 /ft., based on measurements following the TMI accident.
These values are significantly dif ferent considering that the two containment designs are similar.
Clarification of the dif ferences between TMI-1 and TMI-2 with regard to the flood level calculation is essential since use of the TMI-2 value in conjunction with estimated water additions for TMI-1 would result in a calculated flood level in TMI-1 of 6.33 f t. Discuss in detail the dif ferences in containment design which would explain this discrepancy, and provide calculations for TMI-2 (for the maximum flood level experienced during the accident) using the same approach as for the TMI-1.
Response
Our site engineering at TMI-2 has reported the following information:
Total water processed 642,272 gal.
Start level 291.04' D = 8.26' Finish Level 282.78' 10,295 f t.3 /ft.
Using this This is equivalent to 6480 gal. in. or figure for comparison, the maximum water level at TMI-1 would be 5.86'.
During the draindown the RCS leakage was less than 0.1 gpm (144 gpd) and, therefore, considered insignificant.
1 Additionally, since the TMI-2 actual flood level is significantly higher than expected at TMI-1, and also as a result of the fact that as the higher the elevation more equipment is present (less free volume) the slight difference in equivalent gallons / inch is not considered significant.
It should also be noted that the TMI-2 free volume, based on a preliminary calculations, is less than that at TMI-1.
Using assumptions equivalent to those used in the TMI-1 calculations we calculate an equivalent water volume of 6501 gal./in. which correlates very well with the measured number (6480 gal./in.).
Item 6:
Identify provisions, if any, for reducing flood level, e.g.,
use of sump pumps to trans fer water f rom containment to waste holdup tenks.
Estimate the effect of these provisions on flood level in the short and long terms.
I
Response
f At this time there are no provisions to transfer water from any accident mitigation equipment, the containment to any waste holdup tanks.
Before maximum calculated level is reached during LOCA or HELB, recirculation may be initiated.
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'- FOR USE IN UNIT l ONLY
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PAGE 72 3.3 TANKS 3.3.1 BORATED WATER STORAGE TANK (POM)
DESIGN CONOITIONS A.
PRESSURE TEN FOOT COLUMN OF WATER ABOVE TANK TOP.
B.
TEMPERATURE 150 F C.
TANK VOLUME (AS BUILT) 368,600 GALS D.
DOME VOLUME WITHOUT DISCHARGING THRU OVERFLOW LINE 4652 CU-FT 34,800 G ALS E.
VOLUME /FT TANK HEIGHT 855 CU-FT/FT 6t+0 0 G AL/FT F.
LOCATION OF LEVEL TAP (FROM TANK BOTTOM) 7 INCHES NORMAL OPERATING CONOITIONS A.
PRESSURE ATMOS B.
TEMPERkTURE 70 F C.
VOLUME (TOTAL TO OVERFLOW) 49,128 CU-FT 367,482 GALS (US ABLE - FROM TOP O F 2 8+ INCH OUTLET TO OVERFLOW) 46,292 CU-FT 346,276 GALS (UStBLE - FROM TOP OF 8 INCH RECYCLE N0ZZLE TO OVERFLOW) 47,779 CU-FT
.357.392 GALS 1
0.
LEVEL l
56 to 57.5 FT FOR USFJI UNIT I ONLY O1 OATE see 1 sis 76 aEVIS10N 02 1
. FUii USE IN UNIT I ONLY
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PAGE 101 6.2.2 SODIUM HYOROXIDE STORAGE T ANK (BUFFALO)
DESIGN CONDITIONS A.
PRESSURE TEN FOOT COLUMN OF WATER ABOVE TANK TOP B.
TEMPERATURE 150 F C.
VOLUME
~
12,750 GALS 0.
VOLUME /IN TANK HEIGHT 20.7 GAL /IN 248.2 GAL /FT E.
DISTANCE LEVEL TAP ABOVE OUTLET N0ZZLE CENTERLINE 14.5 INCHES NORMAL OPERATING CONDITIONS A.
PRESSURE STATIC HEAD OF FLUID IN TANK B.
TEMPERATURE 70 F C.
LEVEL 30.0 FT 0.
VOLUME (USEABLE ABOVE LEVEL TAP CENTER LINE) 1345 CU-FT l~
SODIUM HYOROXIDE CONCENT iTION.
16,500 LBS i
0F 20 WT PEDCENT l
l l
FOR USE IN UNIT ! ONLY REVISION 02 1101 01 OATE SEP 1 51976