ML18102A474
| ML18102A474 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 10/17/1996 |
| From: | STONE & WEBSTER, INC. |
| To: | |
| Shared Package | |
| ML18102A471 | List: |
| References | |
| 010-1, 10-1, NUDOCS 9610250082 | |
| Download: ML18102A474 (11) | |
Text
-TONE & WEBSTER ENGINEERING CO-RATION
- 5010.65 CALCULATION SHEET -
CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 5
\
/ 02560 UR(B) 010 - 1 N/A
- 1. o Objective The objective of this calculation is to determine the airborne radiation doses at the Exclusive Area Boundary (EAB) , the Low Population Zone (LPZ), and in the control room following a Reactor Coolant Pump (RCP) Locked Rotor Accident (LRA) with the modified control room ventilation system. The calculation assumes a simultaneous Loss of Offsite Power (LOOP) following the high radiation alarm signal generated by the control room intake monitors, with the subsequent delay in switching from the normal operation mode to the emergency operation mode of the control room ventilation system. The calculation utilizes the automatic selection capability *of the radiation monitors to select the less contaminated CR intake. In addition, it assumes that only one Unit's CR emergency ventilation system is
'available.
Additionally, control room operator doses are calculated for a case that assumes the control room is already in the emergency ventilation mode when the accident occurs.
This calculation also determines the proces~ safety limit for the control room air-intake monitors.
- ~ -- --
9610250082 961017 PDR ADOCK 05000272 P PDR
-TONE & WEBSTER ENGINEERING COP~ATION
- 5010.65 9 CALCULATION SHEET 9 CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 9 02560 UR(B) 010 - 1 N/A 3,0 Assumptions
assumed to be 0.01.
The assumption of iodine partition factor in the SGs of 0.01 is appropriate for the portion of the primary leakage which does not flash.
The P-S leakage of 1 gpm wi11* not cause flashing when the steam generator tubes are fully covered with water.
- 2. The X/Q values for the more favorable [Ref .1]
intake are used when the control HVAC .is in emergency mode, taking credit for the automatic selection of the more favorable intake by the control room radiation monitors.
- 3. The time for the control room EACS Fans to (Ref.1]
) reach full speed after restart is assumed to to be 15 seconds.
- 4. The unfiltered inleakage after control room is [Ref .1]
pressurized due to ingress/egress is assumed to be 10 cfm, based on SRP 6.4.
The unfiltered inleakage after control room is pressurized due to ductwork is assumed to be 50 cfm.
- 5. The required filtered emergency makeup flow to [Ref .1]
pressurize the control room is assumed to be 2000 cfm.
. l
-TONE & WEBSTER ENGINEERING CO-RATION
- 5010.65 .., CALCULATION SHEET 9 CALCULATION IDENTIFICATION NUMBER J.O.OR W.0.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 10 02560 UR(B) 010 - 1 N/A 4.0 Data
- 1. Fraction of failed fuel after the accident [Ref.1]
5%
- 2. Fraction of the fuel activity in the gap [Ref.1]
10%
- 3. The gap activity of the failed fuel that is [Ref.1]
released to RCS (0.5% of the core inventory) is presented in Table 1.
- 4. The initial primary coolant activity including [Ref .1]
pre-accident iodine spike is given in Table 2.
The initial secondary coolant activity is also given in Table 2.
- 5. Primary to secondary leak rate - 1 gpm [Ref.1]
\
\
I
.I
- 6. Primary coolant volume - 10,892 cubic feet [Ref.1]
- 7. Steam releases [Ref.1]
0 - 2 hr - 654,600 lbs 2 - 8 hr - 540,300 lbs 8 -32 hr - 2,161,200 lbs
- 8. Post-accident steam generator liquid mass [Ref.1]
106,860 lbs for each steam generator
- 9. Off site X/Q's (from Unit 2 MSSVs) [Ref.1]
) ( SLm 3 )
0-2 hr 1.30E-4 1.86E-5 2-8 hr 7.76E-6 8-24 hr 5.0lE-6 1-4 day 1.94E-6 4-30day 4.96E-7 Unit 2 accident will result in greater doses because of worse X/Q values.
-TONE & WEBSTER ENGINEERING colAIRATION
- 5010.65 CALCULATION SHEET 9 CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 11
'*..-:).. 02560 UR(Bl 010 - 1 N/A
- 10. Off site Breathing rate o- 8 hr - 3.47E-4* m3 /sec. (Ref.1,5]
8- 24 hr - 1. 75E-4 m3 /sec 24-720 hr - 2.32E-4 m3 /sec
- 11. control room intake X/Q's (from Unit 2 MSSVs) (Ref.1]
Unit 1 intake Unit 2 intake (s lm 3
) CS lm 3 )
~ 0-2 hr 1. 96E-3 4.17E-3 2-8 hr 2.13E-3 1. OOE-2 8-24 hr 1.80E-3 8.32E-3 1-4 day 1. 25E-3 5.54E-3 4-30day 7.46E-4 3.09E-3 Unit 2 accident will result in greater doses because of worse X/Q values.
- 12. CONTROL ROOM PARAMETERS - Modified design (Ref .1]
)
- Control room pressure envelope volume:
81, 420 ft 3
- Normal. unfiltered air intake rate:
1200 cfm (1320 cfm including 10% margin)
- Filtered emergency makeup flow- 2000 cfm; see assump.5 (2200 cfm including 10% margin)
- Total unfiltered inleakage- 60 cfm (10 cfm from ingress/egress; 50 cfm from Ductwork leakage; see assumption 4)
- Filtered recir flow rate 5000 cfm - one EACS fan operation
(= 8000 cfm fan capacity- 800 cfm (10% margin)
-2200 cfm makeup flow) 12, 200 cfni - two EACS fans operation ++
(= 16000 cfm fan capacity- 1600 cfm (10% margin)
-2200 cfm makeup flow)
- Intake and recirculating filter efficiencies:
Elemental iodine - 95%
Organic iodine. - 95%
Particulate - 95%
++ ONC: FA/J PER.. E.ACS FIL 'T~A-r10,.J -rR.A1"1.
aiTONE & WEBSTER ENGINEERING COFaRATION
- 5010.65 - CALCULATION SHEET -
CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 12 02560 UR(B) 010 - 1 N/A
- cortrol room occupancy factors: [Ref.1]
Time from Start Occupancy of Accident Factors o to 8 hrs 1. 0 8 to 24 hrs 1. 0 1 to 4 days 0.6 4 to 30 days 0.4
- Breathing rate - 3.47E-4 m3 /sec [Ref.1,8]
- 13. The control room intake damper closure time: [Ref .1]
20 seconds.
- 14. The time for the diesel generators to become [Ref .1]
fully operational after LOOP: 13 seconds
- 15. Data for Control Room Intake Monitors [Ref. 1]
- Monitor response time - Table 6-1 of Ref.[11) [Ref.11]
) The Salem control room monitors are Sorrento Electronic in-duct monitor RD-25A with micro-processor RM-2000. The monitor response time in Table 6-1 of Ref.[11) is for filter constant (FC) equal to 6. FC=6 is the SE recommended value (Ref.[1]).
- Noise reject delay time = 5 x 600 msec
= 3 sec [Ref .1]
The noise reject time count of 5 is recommended by SE (Ref.[1]). 600 msec is the RM-2000 shift register time segment.
- Detector Response - Xe133: 6.21E7 cpm/(µCi/cc) [Ref.12]
Kr85: 2.58E8 cpm/(µCi/cc)
- ." ;"'\ .
- .::.)
-TONE & WEBSTER ENGINEERING COfARATION
- 5010.65 CALCULATION SHEET 9 CALCULATION IDENTIFICATION NUMBER J.0.0R W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 13
) 02560 UR(B) 010 - 1 N/A Table 1 Gap activity in the Failed Fuel*
(Ci)
NlJgliQ.~ Activity I131 4.95E+5 I132 7.00E+5 I133 l.OOE+6 I134 1.10E+6 I135 9.50E+5 Kr85m 1. 30E+5 Kr85 5.50E+3 Kr87 2.35E+5 Kr88 3.35E+5
)
_/
Xe131m 3.50E+3 Xe133m 1. 45E+5 Xe133 1. OOE+6 Xe135m 2.00E+5 Xe135 2.50E+5 Xe138 8.00E+5
- From Ref. [ 1] .
~TONE & WEBSTER ENGINEERING CO-RATION
- 5010.65 W CALCULATION SHEET W CALCULATION IDENTIFICATION NUMBER J.0.0R W.0.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 14 02560 UR(Bl 010 - 1 N/A Table 2 Primary Coolant and Secondary Coolant Activity*
(Ci)
Primary Coolant with Pre-accident Secondary Coolant Iodine Spike 4 Steam Generators N11QliQ.~ AgtiYity NuQlide Activity I131 1.04E+4 I131 1. 28E+l I132 3.58E+3 Il32 4.40E+O Il33 1. 60E+4 ri:p 2~00E+l I134 2.02E+3 I134 2.40E+O I135 8.08E+3 Il35 1.00E+l Kr85m 4.4E+2 Kr85 2.1E+3
.) Kr87 2.6E+2 Kr88 7.8E+2 Xe131m 5.4E+2 Xe133m 4.4E+3 Xe133 6.7E+4 Xe135m 1. 3E+2 Xe135 2.2E+3 Xe138 1. 6E+2
- From Ref.[1].
-TONE & WEBSTER ENGINEERING CO-RATION
- 5010.65 CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 19 02560 UR(B) 010 - 1 N/A 7.2 control Room Intake Monitor Response Time The intake monitor response time is determined by the final count rate at the detector (Ct), the monitor setpoint (Cs), the background count rate (C 0 ) , and the time constant of the micro-processor (RC). The new Salem control room intake monitors consists of Sorrento Electronic beta sensitive in-duct detectors and RM-2000 micro-processor. The smoothing algorithm of RM-2000 will generate an effective time constant for a step change of the detector count rate. The effective time constant depends on the initial count rate, the final cdunt rate, and the smoothing filter constant (fc). The time constant corresponding to the 95% observation time (i.e. 3RC) given in Table 6.1 of reference ( 11) is for fc=6 and will be used to determine the monitor response time.
The detector response function (cpm per µCi/cc) for Xe-133 and Kr-85 are listed below :
Xe-133 - 6.21E7 cpm/(µci/cc)
) Kr-85 - 2.58E8 cpm/(µci/cc)
The process safety setting for the intake monitors is determined in Appendix A to be 4E-5 µci/cc (Xe-133). This value will be conservatively used as the monitor alarm setpoint for response time calculation.
Cs= 4E-5 µci/cc x 6.21E7 cpm/(µci/cc)
= 2484 cpm The initial Xe-133 and Kr-85 concentrations at the control room intake for the design basis RCP LRA are calculated as follows:
Cone= (Gap & RCS activity)/(RCS Volume) x 1 gpm leak rate x (X/Q)
Concxe- 133 = ( 1E6 Ci + 6. 7E4 Ci) / ( 10892 ft3 ) x ( 1 gal/m~n) 3 x (62.4/45.3) x (4.17E-3 s/m3 } / (7.481 gal/ft )
I ( 60 s/min)
. _*'~\ .
=1.25E-3 Ci/m 3 = 1.25E-3 µCi/cc
':._:;.J ConcKr-as = (5.5E3 Ci+ 2.1E3 Ci) /(10892 ft3 )x (1 gal/min)
~TONE & WEBSTER ENGINEERING CO~RATION
- 5010.65 W
- CALCULATION SHEET W CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 20 02560 UR(B) 010 . 1 N/A x (62.4/45.3) x (4.17E-3 s/m 3 ) / (7.481 gal/ft3)
/ (60 s/min)
= 8.93E-6 Ci/m 3 = 8.93E-6 µCi/cc In above calculations, the 1 gpm primary-to-secondary leak rate at room temperature was adjusted by the ratio of primary coolant density at room temperature to that at power operation temperature. (See sect. 7.4 for details.)
The step increase of the instantaneous detector raw count rate at the arrival of the contaminated air is:
Cf - C0 = (1.25E-3 µCi/cc x 6.21E7 cpm/(µci/cc) )
+ (8.93E-6 µCi/cc x 2.58E8 cpm/(µci/cc) )
= 7.99E+4 cpm From Table 6.1 of ref.[11], the three times time constant of the monitor response for a step increase of 1E+4 cpm is 0.95 min.
Therefore, the effective time constant (RC) for a step increase of 7. 98E+4 cpm will be less than 0. 95/3 = O. 317 min. The monitor response time, t*, is determined by:
Cs = C0 + ( Cf - Co) ( 1-e-t*/RC) 2484/79900 = 1-e-t*/o. 317 t* =0.01 min =0.6 sec To avoid spurious alarm due to noise count rate, RM-2000 features a noise *rejection algorithm. The noise rejection response time is equal to the reject time count (5, recommended by SE) multiplied by the_shift register time segment (600 msec).
Therefore, noise rejection response time = 5 x 600 msec = 3 sec The over-all monitor response ,time= 3 +0.6 = 3.6 sec Four seconds will be used as the monitor response time for the RCP Locked Rotor accident.
-TONE & WEBSTER ENGINEERING CO-RATION
- 5010.65 CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.0.0R W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 40 02560 UR(B) 010 - 1 N/A a.o Results and conclusions The calculated EAB, LPZ and control room doses from the airborne source due to a RCP Locked Rotor Accident for the modified control room ventilation design are summarized below. The 10CFRlOO and GDC 19 dose limits are also listed for comparison:
10 percent of Calculated EAB Dose 10CFRlOO Limit Thyroid 0.53 Rem 30 Rem Whole Body 0.11 Rem 2.5 Rem 10 percent of Calculated LPZ Dose 10CFRlOO Limit Thyroid 0.61 Rem 30 Rem Whole Body 0.04 Rem 2.5 Rem
)
Calculated CR Dose with GDC 19 & Equivalent Selection of Better Intake* Dose Limit Thyroid 7.6 Rem 30 Rem Whole Body 0.40 Rem 5 Rem Beta 4.6 Rem 30 Rem
- Automatic selection of the better intake with only one unit EACS operating.
.TONE & WEBSTER ENGINEERING CO.ATIO~
~5010.65 CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE PAGE 41
) 02560 UR(BJ 010 - 1 N/A Calculated CR Dose with ** GDC 19 & Equivalent Pre-existing Emergency Mode Dose Limit Thyroid 18 Rem 30 Rem Whole Body 1. 7 Rem 5 Rem Beta 19 Rem 30 Rem
- Assumes worst case CR intake but that the CR EACS for both units are available.
It is concluded that the calculated doses are within the allowable limits for the RCP Locked Rotor Accident.
The process safety limit for the control room intake monitors is determined in Appendix A based on the more stringent limit of
) the following two criteria:
(1). The control room activity concentration shall be less than 1 Derived Air Concentration (DAC) listed in 10CFR20, Appendix B, Table I, Column 3.
(2). The dose rate contributed by the airborne activity shall not exceed the radiation zone limit of the control room. The control room is designated as radiation zone I with maximum dose rate of 0.25 mr/hr according to FSAR sect.12.1.
The process safety limit is determined to be 4E-5 µCi/cc (Xe-133). The actual monitor setpoint shall include loop allowance and a safety margin.