ML19241B319
| ML19241B319 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/10/1979 |
| From: | Robert Lewis NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Whitt K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| FOIA-79-98 NUDOCS 7907160072 | |
| Download: ML19241B319 (3) | |
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K. V. Whatt, Chief, Performance Appraisal Branch, IE:HQ FRott:
R. C. Lewis, Acting Chief, Reactor Operations and Nuclear Support Branch, Region II
SUBJECT:
REGIsN II CorefENTS ON OCOh*EE RESPONSE TO IEB 79-05 AND 79-05A The cocnents enclosed are keyed to the numbered responses in the Duke Power Company response dated April 10, 1979.
Item 1 Cocnent (1)
Apparently, the licensee did not analyze system operations to determine valve actuation, pump initiation and Engineered Safeguard feature lineup expected for the sequence of events at TMI 2y(Specifically, no mention is made of the normal
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status of the Emergency Feedwater System, power operated s
relief valves or the cross connection status of Emergency Feedwater between Units.
Coment (2)
The analysis of the loss of feedwater event does not assume that the PORV sticks open. The ISAR analysis also does not consider the failure of the PORV in the open position for a loss of feedwater transient.
Connent (3)
The loss of feedwater transient does not consider the situa-tion when the main feed pu=p does not trip but continues running at minimum. speed (e.g.
consider a control oil or gp governor malfunction on the main feed pump turbine). This I
failure would appear to be more severe because the steam f(>> [3 generators would boil dry and the turbine would not trip M
piff of incediately.
B&W plants do not have a reactor trip on p
feedflow steam flow mismatch. Since no main feed pu=p trip occurs the Emergency feed pumps weuld not get a start signal.
CONTACT:
Region II F. Jape, (404) 448-9461 B. Cottle, (205) 264-7755 Duke Power
$$gg B. Gill, (704) 537-9467 R. Tuller, (803) 882-8988 7'-
T. Holland, (704) 364-9533 h
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K. W. Whitt Coment (4)
Under the evaluation of a loss of feedvater followed by a loss of emergency feed water the expected unit response reported by the licensee does not assume an immediate flow of energency feedwater.
Under ites (e) of this part be states that the transient would be similar to the course of coc:plete loss of station power transient described in the FSAR. If no emergency feed water is available at the beginning of the transient. we see no way that the operator would have 30 to 90 minutes to provide feedvater flow.
A reactor coolant pump would not be available under a le of offsite power and we conclude froa the TMI-2 sequence aat a single HPI pump would be inadequate to provide sufficient core cooling.
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Item 2 Coment (1)
Although the IEB did not specifically request them, we believe that the strip chart recorder traces for the reported transients should be provided. This would allow an indepen-dent review of the transients to evaluate any deviatians froa expected performance.
Coment (2)
The analysis of the Davis Besse Incident assumes that forced reeirculation. would be available.
This does not appear to be accurate in that a loss of offsite power.would preclude h
operation of the reactor coolant pumps.
Additionally, the evaluation appears to conclude that no unsafe voiding will gw occur as long as pressure does not decrease below 1600 psi.
This conclusion is disturbing in that there appears to be no margin.
There should be at least a 100 F differential temperature between the pressurizer saturation temperature and the maximum allowed core outlet temperature to ensure that a bubble will not form in the top of the reactor vessel.
Coment (3)
Paragraph (5) of Item 2. discusses an event where the control indication was improper and that Emergency feedwater room pump discharge pressure had taken approximately five minutes to provide accurate indication.
This instrument must be modified to provide imediate and reliable indication to the control room operator that the pump is running properly. It is not clear whether the pump ever reached its required discharge pressure.
The licensee should establish why the emergency header block valve did not open fully.
352343
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I. W. Whitt.
Item 3 Coement (1)
The licensee indicates that only two Emergency Procedures were reviewed to ascertain if any revision vere needed to address void formation.
We feel this review is inadequate and should have addressed operata=g procedures and abnormal transient procedures as well.
Item 4 Coceent (1)
The response appear to be a general caveat t. bat the action specified by paragraphs a, b. (1) and (2) and c of the IEB will be up to the operators discretion. Ve do not believe Duke intends to allow the pressurizer to go solid.
Under what conditions would the operator not carry out steps a, b and c?
Cocment (2)
Implementation of steps b(1), b(2) and (c) have only been included in 2 Emergency Procedures.
Item 6 Coenent (1)
IEB says to prepare and implement all changes necessary to cause containment isolation on a safety injection signal.
The response does nothing more than describe the current design and lineup and is not adequate.
Item 9 Cocnent (1)
No interim instructions to the operations personnel to secure pumping or venting in the event some incident causes unaccept-able concentrations to be discharged out of the contain=ent.
Region 11 inspectors have verified that licensee action indicated in there response (Item have been implemented at Oconee.
1 through 3, 4a and 5)
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C ing Chief Reactor Operations and Nuclear Support Branch cc:
S. E. Bryan
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