ML19330A902
| ML19330A902 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/22/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8007290724 | |
| Download: ML19330A902 (5) | |
Text
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400 Chestnut Street Tower II July 22, 1980 Director of Nuclear Reactor Regulation Attention:
Mr. A. Schwencer, Chief Light Water Reactors Branch No. 2 Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20$55
Dear Mr. Schwencer:
In the Matter of the Application of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328
References:
1.
Letter from H. R. Denton to All Power Reactor I
Applicants and Licensees dated March 28, 1980 2.
Letter from D. G. Eisenhut to All Operating Reactor Licensees dated May 7, 1980 3.
Letter from L. M. Mills to A. Schwencer dated July 18, 1980 In the letter dated March 28, 1980, guidance was provided for the development of a training program to mitigate core damage. A schedule j
for implementation of the new training program was provided by letter i
dated May 7, 1980.
TVA has previously responded to the implementation schedule with a commitment to incorporate the new training program in the training of Sequoyah Nuclear Plant reactor operators. This letter provides details of the new training program.
This program meets the requirements of Enclosure 3 to reference 1.
All reactor operators for Sequoyah will have received this training by August 1, 1980.
Enclosed for your review is a description of the IVA program " Training for Mitigating Core Damage." This program was developed by TVA to ensure that.all licensed operating employees are properly trained to use the information available through installed plant systems to recognize, control, and mitigate an accident in whfch the core is severely damaged.
This training supplements the existing training program.
The program consists of 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> of classroom instruction followed by a 2-hour examination administered at the conclusion of the program.
Very truly yours, TENNESSEE VALLEY AUTHORITY b
C-M. Mills, Manager N
b Nuclear Regulation and Safety
' Enclosure (41) 8007290 f
ENCLOSURE Training for Mitigating Core Damage A.
Incore Instrumentation 1.
Use of fixed or movable incore detectors to determine extent of core damage and geometry changes.
2.
Determining peak temperatures using thermocouples in control room, both indicated and readout on computers.
3.
Methods for extended range readings at the terminal junctions using millivolt potentiometers.
a.
Recorder numbers and location b.
Procedure for setting up and reading test equipment B.
Excore Nuclear Instrument (NIS) 1.
Review of excore nuclear instrumentation system.
2.
Use of NI'I for determination of void formation, void location basis for NIS respo-se as a function of core temperatures and density changes.
C.
Vital Instrumentation Instrumentation response in an accident environment with particular emphasis on post accident monitors (PAM).
Instrumentation to be discussed: primary system pressure, temperature, level; containment pressure, temperature, level; neutron level; and steam generator level.
1.
Instrument failure mode during loss of instrument power or other predictable failures (e.g., loss of reference leg).
2.
Containment pressure, temperature, radiation, and moisture effects on readings.
3.
Expected degree of accuracy following parameter's return to normal.
4.
Alternate means of determining approximate value for critical parameters assuming the primary method of measurement has failed.-
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C.
Vital Instrumen ation (continued)
Determination of pressurizer level if all level transmitters a.
fail b.
Determination of letdown flow with a clogged filter (low flow) c.
Determination of other Reactor Coolant System parameters 5.
The use and capabi'.ity of the plant computer in monitoring and analyzing critical parameters.
6.
Isolation philosophy, signals, instrumentation, and potential failure modes.
D.
Primary Chemistry Results with Core Damage 1.
Initial Detection a.
Chemistry parameters b.
Failed fuel detectors 2.
Determination of extent of damage a.
Methods of sampling and analysis
.t (1) Gamma-ray isotopic (2) Gases b.
Time requirements for sampling and analysis c.
Indications of:
(1) Clad defects
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(2) Messive defects (3) Fuel melting d.
Additional sampling and analysis (1) Reactor coolant system (2) Containment 3.
Consequences of damage Activity levels in coolant and total activity in core a.
b.
Contamination considerations c.
Feleases to containment 1
n.
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9t D. - Primary Chemistry Results with Core Damage (continued)'
d.
Releases to environment Personnel exposure during sampling and analysis e.
4.
Corrosien effects a.
Zircaloy/ water reaction b.-
Submersion of equipment and time to failure 1
c.
Emergency chemistry controls E.
Radiation Monitoring 1.
Response of process and radiation monitors to severe core damage.
2.
Behavior of monitors and detectors when saturated.
3.
Methods of detecting radiation readings by direct measurement at detector output signal.
4.
Expected accuracy of monitors Et different locations.
5.
Use of monitors to determine extent of core damage.
6.
Radiation monitor failure modes.
7.
Methods of determining dose rate inside containment from measurements taken outside containment.
F.
Gas Problems under Accident Conditions
-1.
Hydrogen a.
Sources b.
Hazardous soncentrations c.
Methods of measuring concentration d.
Venting e.
H recombiners 2
2.
-a.
Containment,....
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i F.
Gas Problems under Accident Conditions (continued) t
~ 3.
Other gases J
a.
Noncondensables - Xe, Kr, and Ar I
b.
Accumulation in coatainment c.
Venting and leakage i
t
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