ML20199L128
| ML20199L128 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 11/24/1997 |
| From: | Stetka T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Terry C TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| References | |
| 50-445-97-12, 50-446-97-12, NUDOCS 9712010311 | |
| Download: ML20199L128 (4) | |
See also: IR 05000445/1997012
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AR LINGTON, fi X AS 76011 8064
November 24, 1997
Mr. C. L. Terry
TU Electric
Group Vice President, Nuclear
ATTN: Regulatory Affairs Department
P.O. Box 1002
Glen Rose, Texas 76043 -
SUBJECT: NRC INSPECTION REPORT 50-445/97 12;50-446/97 12
Dear Mr. Terry
Thank you for your letter of C:tober 3,1997, in response to our letter dated
. September 4,1997, which requested additional information concerning your July 10,
1997, response to our letter and Notice of Violation dated June 11,1997. In this letter,
you provided additional information concerning the generic implications of multiple
diaphragm valve f ailures and the causes for previous failures to identify a slow stroking
main feedwater isolation valve. We have reviewed your reply and find it responsive to the
questions in our letter. We will review the implementation of your corrective actions
during a future inspection to determine that full compliance has been achieved and will be
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maintained.
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Sincerely,
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Thomas F. Stetka, Acting Chief
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Engineering Branch
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Division of Reactor Safety
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TU Electric
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cc:
Mr. Roger D. Watner
TU Electric
Regulatory Affairs Manager
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P.O. Box 1002
Glen Rose, Texas 76043
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Juanita Ellis
President CASE
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1426 South Polk Street
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Dallas, Texas 75224
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TU Electric
Bethesda Licensing
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3 Metro Center, Suite 610
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Bethesda, Maryland 20814
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George L. Edgar, Esq.
Morgan, Lewis & Bocklus
1800 M. Street, NW
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Washington, D.C. 20036 -
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G. R. Bynog, Program Manager /
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Chief Inspector
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-Texas Department of Licensing & Regulation
Boiler Division
P.O. Box 12157, Capitol Station
Honorable Dale McPherson
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County Judge
P.O. Box 851
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Glen Rose, Texas 76043
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Texas Radiation Control Program Director
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1100 West 49th Street
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John Howard, Director
Environmental and Natural Resources Policy
Office of the Governor-
P.O. Box 12428
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TU Electric
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E Mail report to T. Frye (TJF)
E Mail report to T. Hiltz (TGH)
E Mail report to NRR Event Tracking System (IPAS)
E Mail report to Document Control Desk (DOCDESK)
bec to DCD (IE01)
bc: distrib. by RIV:
Regional Administrator
Resident inspector (2)
DRP Director
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DOCUMENT NAME: G:\\ REPORTS \\CP712.AK
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E Mail report to Document Control Desk (DOCDESK)
bec to DCD (IE01)
bec distrib, by RIV:
Regional Administrator
Resident inspector (2)
DRP Director
DRS PSB
Branch Chief (DRP/A)
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Project EnD neer (DRP/A)
RIV File
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Branch Chief (DRP/TSS)
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DOCUMENT NAME: G:\\ REPORTS \\CP712. AK
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Log i TXX 97194
File # 10130
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IR 97 12
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October 3. 1997
C. l.arue hrty
can,us, a e bruhm
U. S. Nuclear Regulatory Commission
Attn:
Document Control Dest
Washington, D.C.
20555
SUBJECT : COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NO. 50 445 and 50 446
NRC INSPECTION REPORT N05. 50 445/97 12 and 50-446/97-12
RESPONSE 10 REQUEST FOR ADDITIONAL INFORMATION
REF:
1)
TV Electric Letter TXX 97143, dated July 10, 1997 to
the NRC
2)
NRC Letter, dated September 4.1997 to TV Electric
requesting additional information
Gentlemen:
TU Electric provided response to the Notice of Violation (NOV) for the
subject NRC Inspection Report via Reference 1.
V1a Reference 2. your
staff requested additional information with respect to examples 3 and 4 of
Violation B and V1olation D.
The information requested, as we understand it, and t-
'osponses are as
follows:
UDIAllDfL3.:
Example 3:
. provide details regarding your correct 1ve actions taten
fully assess the generic imp 11 cations of the Incorrect Installation of
the finger plates in the 500 diaphragm valves."
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Response:
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As stated in the subject inspection report section M7.1 (b). TU Electric '
initiated an Operations Not1fication and Evaluation (ONE) Form to document
the review performed for generic 1mplication; of the finger plate 1ssue.
It was also discussed with the NRC inspection team that the probable cause
for incorrect installation of the finger plates was c less than adequate
procedure, which did not provide guidance for installation of the finger
plates.
Please note that approximately 300 diaphragm valves (not 500 as
stated in reference 2) In both safety-related crui nonsafety-related
systems were reviewed
it was determined by engineering that further
actions were required for the valves which met all of the following
criteria.
a)
Valves that had a diaphragm replaced before the procedure was
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revised to provide guidance, regarding installation of the
b)
valves that contain a finger plate;
c)
valves that fully open to perform a safety function; and
)
d)
valves that have not been flow tested to date.
Two valves met the above criteria, the subject valves could not be flow
tested and were therefore disassembled and inspected.
The inspection
results were favorable, i.e., the finger plates were assembled correctly.
Example 4; L . .we considered your corrective actions stated in
LER 96-02, addressing the metal fragment problem in the main feedwater
isolation valve solenold, to be adequate.
However, your response did
not provide detatis regarding the ren ons that corrective actions were
not developed for previous slow stroking occurrences and the actions you
plan on taking to prevent a recurrence of this corrective action
problem."
Respunse:
The previous slow closures of the feedwater isolation valve were
documented on either an Op"ation Notification and Evaluation (ONE) Form;
or on the other documents such as a work request; or the Post Reactor
Protection System or Engineered Safety Features Actuation Evaluation
forms.
These events,
i.e.. slow closures were evaluated by engineering
and were dispositioned as limit switch problems.
Based on this
disposition. the limit switches were replaced and/or reworked, the valve
were tested and returned to Operable status.
TV Electric believes that
the valve was not left in an inoperable condition for an extended period
of time.
Nonetheless. TV Electric shares the concerns stated in the
inspection report that it missed an opportunity to correct the problem if
it had initiated a ONE Form for each occurrence.
Which would have
triggered a formal root cause and preventive action process.
The actions
to prevent recurrence with respect to failure to initiate a ONE Form have
been identified via Reference 1.
Please note that the slow closure of the feedwater 1 solation valves
(FWlVS) was not discovered before the January 1996 trip for the following
reasons:
e)
Before the January 1996 trips, there was no guidance for Plant
Operators to check the closure times of the FWlV's after 6 plant
trip.
b)
The last regularly scheduled time response tests showed proper
closure times of the valves.
c)
The feedeter regulating valves (FRVs). which function as non-
safety related backup to the FWlVs functioned properly to isolate
feedwater; as a result, no unusual plant response was identified
which may have suggested a problem with the FWlV closure time.
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1 hat is, proper operation of the FRV masked the slow operation of
the FWlV.
Although the Plant Operators check their panel to verify that they have
proper shut indication from thc FWlVs. this check is to verify that the
valve; are in the correct position, and is not required to be performed
within the 6.5 second response time of the valve (such a requirement
would not be appropriate).
Therefore. FWlVs could close in greater than
6.5 second but still be closed at the time the Plant Operator verifies
proper indication on the panel.
The problem was identified during the January 1996 trip because the
failure that caused the trip shut the FWIVs. but did not shut the FRVs.
As a result, the number 2 steam generator (SG) water level behaveu
dif ferently for the other steam generators,
investigation of this
difference in equipment response led to the discovery to the slow closure.
To have a slow closure. either there must be a mechanical problem with the
valve / actuator (which would have shown up with the stroke testing), or
both Nitrogen solenoid valves (2 HV 2135 SV3 & 2 HV 2135 SV4), or both oil
dump lines (i.e., oil dump solenoid [2 HV-2135-SV1 & 2-HV 2135 SV2] or the
associated pilot check valve and oil drain lines) must be slow.
To prevent recurrence, during January 1996, all 4 solenoid valves were
caanged on the FWlV.
The stroke time tests were performed satisfactorily,
and train related time response tests did not reveal any matters of
Time response tests were repeated to verify consistency of the
concern.
closure times,
Additionally. Operations procedures were changed to
include checking closure time as part of the post tr1p checks.
VIOLATION _D:
.. Violation D did not specify when the temporary shielding procedure
would be revised.
We request that you prov1de a completion date for
these procedural revisions."
Response:
The procedure RPI-608. " Control of Temporary Shielding * was revised and
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approved on July 28. 1997.
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Should you have any coments or require additional information, please do
not hesitate to contact Oba1d Bhatty at (254) 897-5839 to coordinate this
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effort.
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Sincerely,
e. $.1
C. L. Ter %
ry
By:R5ger%
l) Walker
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Regulatory Affairs Manager
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OB:ob
cc:
Mr. E. W. Merschoff, Region IV
Mr. J. 1. Tapia, Region IV
Resident Inspectors
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