ML19338D906
| ML19338D906 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 07/11/1980 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Hanauer S, Mattson R, Vollmer R Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19338D883 | List: |
| References | |
| OREM-80-010, OREM-80-10, NUDOCS 8009240158 | |
| Download: ML19338D906 (5) | |
Text
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ENCLOSURE 2
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- [D,.f[k UNITED STATES y
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g/. j wAswiNotow. o. c. 20sss JUL 11 1980 MEMORANDUM FOR: Richard H. Vollmer. Director Division of Engineering Roger J. Mattson, Director, Division of Safety Technology Stephen H. Hanauer, Director, Division of Human Factors Safety Denwood F. Ross, Director, Division of Systems Integration Bernard J. Snyder, Program Director TMI Program Office Brian K. Grimes, Program Director, Emergency Preparedness Program Office FROM:
Darrell G. Eisenhut, Director, Division of Licensing
SUBJECT:
OPERATING REACTOR EVENT MEMORANDUM NO. 80- 10 :
OPERATING REACTOR EVENTS WHICH OESULT IN CONTAINMENT FLOOR FLOODING PROBLEM it summary of 15 LERs which describe events at operating reactors which
?sulted in quantities of water on the containment floor greater than luv0 gallons. Volumes less than 1000 gallons were considered i
insignificant because they are about the size of the containment sumps.
It should be noted that other flooding events may have occurred and not have been reported as LERs.
BACKGROUND The events listed in the enclosure resulted in between 1000 gallons and 600,000 gallons (TMI-2 Accident) being released to the containment.
The average amount, disregarding the TMI-2 accident, is about 30,000 gallons.
These occurrences, except. for the TMI-2 accident, have resulted in little or no measured radioactive effluents frem containment and no reported equipment damage from the water, The water is normally primary coolant water released from the RCS because of main coolant pump seal failure. Another pathway is the lifting of i
the pressurizer PORV and/or code safety valves to the pressurizer relief
.L tank with the rupture of the relief tank rupture disk allowing flow to the containment floor. Enclosure 2 is a diagram of the reactor coolant l
system with the pressurizer PORV and the pressurizer relief tank. To date, two plants, TMI-2 and Crystal River 3, have released significant I
quantities of water to containment via this pathway. These events are also listed in Enclosure 1.
1
_l_S_E_._..,___.-
8009240
Multiple Addressees.
JUL 11 1980 SAFETY SIGNIFICANCE Uater on the containment floor seems only to be significant during a major loss-of-coolant accident. The amount of water available to containment for a typical nuclear plant is several hundred thousand gallons and may go over one million gallons. This water can be from the reactor coolant system (about 80,000 gallons), the refueling or borated water storage tank (up to 1,000,000 gallons), and the condensate storage tank (about 500,000 gallons). The amount of water in the TMI-2 containment after the accident was about 600,000 gallons. These volumes are significantly greater than the amounts of water listed in Enclosure 1 for non-accident operational occurrences.
In general, we see minimal safety concerns with excess water on the containment floor during operational occurrences.
Excess coolant injection during these events is preferrable to a TMI situation where ECCS systems were throttled backed. The staff is concerned, however, with the initial causes of these events such as the frequency of RCS pump seal failures and transients which lead to pressurizer relief 1
valves openings. AE0D is looking into RCS pumo seal failures but is not expected to reach any conclusions soon.
DST is following these N
devel opmen ts. The concerns on transients which lead to pressurizer i
relief valve openings is being handled through short term Lessons 2
Learned (L ) and NUREG-0660.
Another concern is that ESF equipment and useful non-ESF equipment in containment may become submerged during an accident and f il to operate.
This is part of the basis for the ACRS short term TMI-2 L requirement for containment water level instramentation.
URR branches review the placement of ESF equipment inside containment with respect to the post-accident water level by requiring all ESF equipment to be qualified for operating submerged or to be located above the maximum design basis water level for the LOCA. NRR branches do not review the placement of non-ESF equipment inside containment, unless it affects an ESF system, with respect to post-accident water' levels.
This may include equipment which may be useful during an accident. An example would be the TMI-2 pressurizer level indicator transmitters, which were relied on during the recovery from the accident.
In addition, the maximum water level defined for TMI-2 during an LOCA was exceeded during the accident probably because the ECCS recirculation was not used.
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, Multiple Addressees JUL 11 1980 4
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.s ACTIONS BEING TAKEN
';RR efforts in this area of concern are in Generic Task B-ll, flooding of aquipment important to safety and in Action Item II.F.5, Classification of Instrumentation, Control and Electrical Equipment TMI-2 Accident Action Plan, NUREG-0660.
Lead DL Manager:
D. Verrelli (X27872)
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i
,lhabi is <f Darrell G.
1sennut, Director Division of Licensing
Contact:
J. Donohew, X28901 1
Enclosure:
As stated cc w/ enclosure:
[,'
H. Denton C. Michelson DL ads DL BCs M. Ernst V.-Noonan P. Check E. Jordan 1
J. Donohew K. Wichman C. Berlinger D. Verrelli M
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WATER IN CONTAINMENT _
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Quantity of H O (gall.)
Event Reactor.
Date LER#
2 TMI-2 3/28/79 600,000 PORV Failure H.B. Robinson 2 5/1/75 75-01T 132,500 RCP Seal Failures Indian Point 2 7/2/77 77-01T 90,000 RCP Seal Failure Arkansas 1 5/80 60,000 RCP Seal Failure Crystal River 3 2/26/80 80-010/
40,000 Instrument and Control OlT-1 System Failure Zion 1 6/5/75 75-OlT 15,000 Personnel Error Valve Left Open
' Salem 1 10/21/78 78-070 15,000 RCP Seal Failures OlT-0 Ginna 1 8/15/75 75-OlT 12,000 Personnel Error Refueling Water N
Storage Tank Brunswick 1 12/1/79 79-091 10,700 Recirculation Pump 03L-0 Valve. Failure Point Beach 1 6/20/77 77-OlT 7,000-Pressure Sensing Line Failure Haddam Neck 1 8/21/77 77-99X 4,020 RCP Seal Failures Fort Calhoun 1 1/1/77 77-03L 3,360 Operator Error-Containment Spray.
Brunswick 2 8/24/75 75-OlT 1,500 RCP Seal 9/5/75 2,600 Failures Duane Arnold 7/20/74 74-OlT 507 GPM*
Check Valve Failure iPalisades'1 10/23/72 72-OlT 28 GPM*
Control Rod Drive Seal Failure
- LERs do not give total leakage to containment w.
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WATER i
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g CVCS - CHIMl* AL AND VOLUME CONTROL SYSTEM p
SIS - SAFETY INJECTION SYETEM m Q RHR$ - RESIDUAL HE AT REMOVAL SYSTEM 2
LJ 41 WPS - WASTE PROCESSING SYSTEM i
s ORAIN HEACER (WPS)
A ik AUXill A R Y ST E AM SPRAY (CVCSI OUTLET y
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P R E SSURIZ E R JL STEAM
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W-FEEDWATER INLET j
NEATER CCNTROL l
REACTOR COOLANT PUMP
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C (CV CSI COLO LEG HOT LEG LJ (T Y PICAL)
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O E CELUGE RESIDUAL.
INJECT N (SIS)
HEAT REMOVAL
($gs; LOOP (RHR$1 CH AR GING ~>
RISIDUAL LINE (CVCS)
HEAT REMOVAL LOOP (RHRS)
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- CvCS:
Figure 12. Reactor Coolant System, Flow Diagram 7
EksLOSURE 3 ga =<cw o
UNITED STATES
[ h e.g NUCLEAR REGULATORY COMMISSION egg,j. f wassincton. o. c. rosss
- y, '.W[f JUL 11 1980 MEMORANDUM FOR: Richard H. Vollmer, Director, Division of Engineering Roger J. Mattson, Director, Division of Safety Technology Stephen H. Hanauer, Director, Division of Human Factors Safety Denwood F. Ross, Directo, Division of Systems Integration Bernard J. Snyder, Program Director, TMI Program Office Brian K. Grimes, Program Director, Emergency Preparedness Program Office FROM:
Darrell G. Eisenhut, Director, Division of Licensing
SUBJECT:
OPERATING REACTOR EVENT MEMOPANDUM NO. 80- 11 :
ARKANSAS NUCLEAR ONE, UNIT 1 - REACTOR COOLANT PUMP SEAL FAILURE PRC3LEM AND BACKGROUND At 1:45 a.m., CDT, Saturday, May 10, 1980, the :ung seal for primary rea: tor coolant pu p (RCP) C at Arkansas Nuclear One, Unit i experienced a leak that eventually released approximately 60,000 gallons of reactor coolant water into the containment.
A leak of approximately 12 gpm was discoved while the operators were performing the norr.31 procedure for leakage rate determination.
Technical Specifications require shutdown if tnat reactor coolant system leakage is greater than 10 gpm.
As the reactor was being brought to a normal controlled shutdown, the leakage rate increased until, when the reactor coolant pump was secured (shut off at 3:00 a.m.), the leakage was 200 to 300 gpm.
The reactor was tripped at 2:50 a.m.
High pressure injection was manually used for make up coolant by operating and throttling charging pumps.
The small break LOCA procedures were used to control the transient.
Pressurizer level and pressure were used to control make up coolant. Margin to saturation was at least 100 F at all times.
Decay heat removal was initiated by the RHR pumps at 9:00 a.m.
For their conve:11ence, the operators closed the core flood tank isolation valves to bring the reactor to a cold shutdown and therefore atmospheric pressure.
These valves are required by Technical Specifications to be locked wer to the a
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operati te breakers which DUPLICATE DOCUMENT Entire docurent previously entered into system under:
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