ML20064N505
| ML20064N505 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 09/01/1982 |
| From: | Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 18809, NUDOCS 8209080393 | |
| Download: ML20064N505 (9) | |
Text
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s O Consumels power Jentes W Cook Vsce President - Projects, I?ngineering and Construction General Offices: 1945 West Pernell Road, Jackson, MI 49201 * (517) 788 0453 l
September 1, 1982 Harold R Denton, Director Office of Nuclear Reactor Regulation Division of Licensing US Nuclear Regulatory Commission Washington, DC 20555 MIDLAND NUCLEAR C0 GENERATION PLANT MIDLAND DOCKET NOS 50-329, 50-330 REACTOR COOLANT PUMP SEIZURE SAFETY ANALYSIS FILE: 0505.16 SERIAL:
18809
Reference:
Letter from R L Tedesco to J W Cook dated June 25, 1982
Enclosure:
Midland FSAR Change Notice 3496, Offsite Dose Calculation Related to Reactor Coolant Pump Seizure The referenced letter requested additional information regarding fuel damage during a postulated reactor coolant pump seizure. This subject is Confirmatory Issue 31 in Section 1.8 of the Midland Plant SER (NUREG-0793).
Since the information requested would be difficult to obtain, the fuel which is calculated to undergo DNB during the transient has been assumed to fail and a dose calculation performed.
The enclosure is the dose calculation for a reactor coolant pump seizure from a 1/1 pump corubination as it will appear in the Midland Plant FSAR. Using the assumption stated above, 27% of the fuel is failed in this analysis. Even so, the offsite doses associated with this bounding analysis are acceptable. The dose calculation does not change the conclusion of the FSAR analysis that the cladding temperature remains sufficiently low to prevent fuel failure.
JWC/JRW/fms CC RJCook, Midland Resident Inspector RHernan, US NRC DBMiller, Midland Construction (3)
RWHuston, Washington 8209080393 820901
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QUALITY ASSURANCE PROGRAM SAR CHANGE NOTICE l
1.PSAR 1
FSAB
- 2. DISCIPLINE / COMPANY Nuclear
- 3. No.3496 JOB NO.
7220
- 4. ORIGINATOR K C Prasad/J Ramanuja
- 5. DATE_ 8-9-82
- 6. REFERENCED SECTIONS OF SAR 15.3.3.5 List of Tables in Accident Analysis, Chatper 15
- 7. DESCRIPTION OF CHANGE 1.
Changed the write up of 15.3.3.5 on Radiological consequences of reactor coolant pump shaft seizure accident.
2.
Added Table 15.3-10 which lists the parameters used in the analysis.
3 Added Table 15.3-11 which lists the resulting offsite doses.
- 8. REFERENCED SPECIFICATIONS OR DRAWINGS None l
- 9. JUSTIFICATION Confirmatory open item of SER
- 10. BECHTEL DISCIPLINE INTERFACE REVIEW:
INTERFACING STAFF REVIEW:
l O ARCH O PLANTDSN O ARCH O MECH O CIVIL O PQAE OCML O NUCLEAR O CONTROLSYS O STRESS O CONTROLSYSTEM O PLANT DSN O ELEC GSOTHER IhS O ELEC O RELIABILITY f MECN! NUCLEAR O GEOTECH O STRESS OM&QS O OTHER K C Prasad 8/10 M J Wylie 3/10/8:
J R Wahl 3/30/82 l
- 11. REVIEWED BY DATE
- 12. REVIEWED BY DATE
- 13. REVIEWED BY DATE (Group Supervisor)
(SAR COORDINATOR)
(NUCLEAR ENGINEER)
N H Eidsmoe 3/23/82 Gary E Clyde 3/26/82
- 14. CONCURRENCE BY DATE
- 15. APPROVED BY (CPCo)
DATE
- 16. CONCURRENCE BY DATE (PROJECT ENGINEER)
(NSSS SUPPLIER)
AA G 110473 REV 9 79 MIDLAND
e MIDLAND 1&2-FSAR 0C03436 drops below 1.3, but the hot spot fuel cladding surface temparature is insufficient to initiate an appreciable metal-f watsr reaction or result in clad damage induced by melting.
l Internal fuel pin pressure does not significantly increase as a 44 romult of the fuel temperature change.
Therefore, rupture at low I
cladding temperature is precluded.
The percentage of fuel pins 4
which would experience a DNBR less than 1.3 is provided in 16 Tablo 15.3-9.
44 15.3.3.4 Barrier Performance Tha locked rotor accident does not result in excessive reactor coolant system pressure and the cladding temperature does not excasd limits.
The integrity of the reactor vessel is maintained.
15.3.3.5 Radiological Consequences
/YW, This event will re 1
in the release of steam from the sec dary cida to the atmosp ere.
It is shown in Subsection 15.3.
.a that l33 fual damage will pot / occur.
For this reason there wi be no incranse in radioactivity in the reactor coolant,or'in the steam.
Bccause the dose are a function of the amount of steam released, tha potential ra 'ological consequencen of'this event will be loss severe than consequences-of if nonemergency ac powar to~ the station as ciscus' sed ir etion 15.2.6.
15.3.4 REACTOR COOLANT PUMP SHAFT BREAK Tha loss of reactor coolant flow due to a pump shaft breakage or other mechanical malfunction has been examined for its effects on cora integrity.
The frequency of occurrence of this accident is expncted to be the same as that for any gross mechanical failure of tha primary system.
Therefore, only one pump is assumed to be af fccted.
Tha effects of the loss of reactor coolant flow due to a pump sheft break are bounded by the consequences of the locked-rotor accident, discussed in Subsection 15.3.3.3.2.
The flow coastdown l33 rceulting from the breakage of one pump shaft is less rapid than thnt resulting from a shaft seizure situation indicative of the locksd-rotor accident.
In either case, the reactor is tripped if in:ufficient reactor coolant flow exists for the power level.
Tha mnrgin of core protection indicated by the DNBR during the coastdown is greater for the pump shaft breakage than for the caso of shaft seizure since the flow decrease is not as rapid.
Thuc the power / imbalance / flow trip function of the reactor protection system ensures adequate protection of core integrity.
k Revision 44 l
15.3-8 6/82
Insert 1 This event will result in the release of steam from the secondary side to the atmosphere. Even though it is shown in Subsection 15.3.3.3 that fuel cladding failure will not occur, radiological consequences of the accident are estimated by conservatively assuming that all the fuel pins that experience DNB will release their gap activities to the reactor coolant. Following the instantaneous seizure of a reactor coolant pump rotor, the reactor trips on a flux / flow signal.
It is assumed that loss of offsite power occurs coincident with the reactor t rip. Major issumptions and parameters used in the analysis are itemized in Table 15.3-10 and are listed below:
a.
Twenty-seven percent of the fuel pins would experience a DNBR less than 1.3.
The gap activity from these pins is instantaneously released to the reactor coolant system. The gap activities are taken from Table 15.A-2.
This activity is assumed to mix uniformly in the circulating volume of the reactor coolant.
b.
The primary coolant leak rate to the secondary system is 1 gpm.
c.
One-hundred percent of the noble gases in the reactor coolant which leak into the secondary side are released to the atmosphere.
d.
Some of the leaking reactor coolant flashes to steam as it enters the steam generator.
Iodine activity contained in the fraction of the reactor coolant that flashed into steam is released instantaneously.
Based upon the energy balance, it is estimated that 13% of the reator coolant will flash into steam. Ten percent of the remaining iodine activity in the steam generator is eventually released to the environment. Therefore, a total of 21.7% of the iodine leaking into the steam generator is released to the atmosphere.
The fraction of reactor coolant that flashes to steam decreases as the reactor coolant temperature decreases. However, in this analysis it is conservatively assumed that 21.7% of the iodine contained in the leaking reactor coolant is released to the environment for the duration of the accident.
e.
No credit is taken for the isolation of the leaking steam generator after 55 minutes following the operations sequence discussed in Subsection 15.2.6.2.
It is assumed that releases will occur for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> following the accident.
f.
No credit is taken for ground deposition or decay during transit to the exclusion area boundary or the outer boundary of the low population zone (LPZ).
The realistic analysis assumes that the radiological consequences are bounded by the radiological consequences of loss of non-emergency AC power to the station auxiliaries discuesed in Subsection 15.2.6.
miO882-1243a131
o 2
The activity release pathways are shown in Section 15B.I.
The mathematical models used in the radiation doses are given in Section 15B.2.
The atmospheric dispersion factors at the site exclusion boundary and at the outer boundary of the LPZ are given in Table 15.3-10 and are based upon site meteorological data as described in Subsection 2.3.4.
The thyroid dose via inhalation and whole-body gamma and skin doses due to cloud immersion have been analyzed for an individual at the exclusion area boundary ano the outer boundary of the LPZ. The resulting doses are given in Table 15.3-11 and are round to be well below the guidelines of 10 CFR 100.
The control room ventilation system is designed to isolate and pressurize the control room upon a high radiation signal from the radiation detector located in the contrl room air intake. For this reason, the radiation doses to control room personnel are considered to be bounded by the control room doses calculated for a LOCA as discussed in Subsection 15.6.5.
The detailed design of the control room ventilation system is given in Section 6.4 and Subsection 9.4.1.
l miO882-1243a131
TABLE 15.3-10 PARAMETERS USED IN EVALUATING THE RADIOLOGICAL CONSEQUENCES OF A REACTOR COOLANT PUMP SHAFT SEIZURE ACCIDENT.
Conservat{yy Parameter Analysis Power 1cvel, Hwt 2552 Fraction of failed fuel during 27 the accident, percent Core Gap Activity Table 15.A-2 Reactor coolant equilibrium Table 15.A-4 activities prior to accident 3
Volume of Reactor Coolant, ft 10,679 Density of Reactor Coolant, g/cc 0.718 Activity Release Data Release Assumptions Fraction of noble gases 100 4
released, percent Fraction of iodines released Fraction flashing as steam, 13 l
percent 10% of iodine remained in 8.7 steam generator Total percent iodine released 21.7 l
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miO882-1243b131
Table 15.3-10 (Continued)
Conservative Parameter Analysis Activity released to atmosphere 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> Isotope Curies I-131 5.13 E+2 I-132 5.57 E+1 I-133 1.00 E+2 I-134 5.97 E+0 I-135 3.20 E+1 KR-83M 1.90 E+1 KR-85M 8.48 E+1 KR-85 7.50 E+2 Kr-87 4.47 E+1 KR-88 1.38 E+2 XE131M 1.53 E+2 XE133M 1.53 E+2 XE-133 1.40 E+4 XE-133 1.40 E+4 XE135M 2.04 E+1 XE-135 3.22 E+2 XE-138 2.39 E+1 Dispersion Data Distance to Exclusion Area 500 Boundary, meters Distance to LPZ Outer 1600 Boundary, meters Atmgspheric Dispersion Factors, S/m Exclusion Area Boundary 4.49 E-4 0 to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />)
LPZ Outer Boundary 8.49 E-5 (1) For the realistic analysis, it is assumed that the radiological consequences are bounded by the radiological consequences of loss of non-emergency power to the station au).liaries discussed in Subsection 15.2.6.
miO882-1243b131
e TABLE 15.3-11 RADIOLOGICAL CONSEQUENCES OF A REACTOR COOLANT PLMP SIIAFT SEIZURE ACCIDENT Conservat{yg Analysis Exclusion Area Boundary Dose (0 to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />), rem Thyroid 31.4 Skin 2.9 E-2 Whole Body Gamma 3.8 E-2 LPZ Outer Boundary Dose (Duration), rem Thyroid 23.7 Skin 2.2 E-2 Whole Body Gamma 2.9 E-2 (1)For the realistic analysis, it is assmned that the radiological consequences are bounded by the radiological consequences of loss of non-emergency power to the station auxiliaries discussed in Subsection 15.2.6.
miOS82-1243b131
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CONSUMERS POWER COMPANY Midland Units 1 and 2 Docket No 50-329, 50-330 Letter Serial 18809 Dated September 1, 1982 At the request of the Commission and pursuant to the Atomic Energy Act of 4
i 1954, and the Energy Reorganization Act of 1974, as amended and the Commission's Rules and Regulations thereunder, Consumers Power Company submits the dose calculation for the reactor coolant pump seizure accident (SCN 3496).
I i
CONSUMERS POWER COMPANY By J
Cook, Vice President Proje s, Engineering and Construction j
1 Sworn and subscribed before me this 1 day of September, 1982
~ -
. Notary Public
/
j.
Jackson County, Michigan My Commission Expires September 8, 1984.
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