ML20210V429
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| ML20210V429 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 02/12/1987 |
| From: | Gagliardo J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Deddens J GULF STATES UTILITIES CO. |
| References | |
| EA-86-183, NUDOCS 8702190018 | |
| Download: ML20210V429 (1) | |
See also: IR 05000458/1986036
Text
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FEB 1 2 1987
In Reply Refer To:
Docket: 50-458/86-36
EA 86-183
Gulf States Utilities
ATTN: Mr. James C. Deddens
SeniorVicePresident,(RBNG)
Nuclear Licensing
P. O. Box 220
St. Francisville, Louisiana 70775
'
Gentlemen:
Thank you for your letter of January 28, 1987, in response to our letter
and Notice of Violation dated December 29, 1986. We have reviewed your reply
and find it responsive to the concerns raised in our Notice of Violation. 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.
Sincerely,
- GMnel 0,3ned cy
J. C. GCC!lardo
J. E. Gagliardo, Chief
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Reactor Projects Branch
cc:
Gulf States Utilities
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ATTH: J. E. Booker, Manager-
l River Bend Oversight l P. O. Box 2951
Beaumont, Texas 77704
Louisiana State University,
Government Documents Department
Louisiana Radiation Control Program Director
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January 28, 1987
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File Nos. G9.5, G15.4.1
U.S. Nuclear Regulatory Commission
Document Control Desk
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Gentlemen: y
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River Bend Station - Unit 1
Refer to: Region IV
Docket No. 50-458/ Report 86-36/EA 86-183
This letter responds to the Notice of Violation, "NRC Inspection
Report No. 50-458/86-36", transmitted to Gulf States Utilities
Company (GSU) in a letter dated December 29, 1986. That letter
refers to an inspection performed by Mr. D. D. Chamberlain during
the period October 12-23, 1986 of activities authorized by NRC
Operating License NPF-47 for River Bend Station.
GSU's response to Notice of Violation 458/8636-01, " Failure to
Meet the Requirements of 10CFR50.59", is provided in the enclosed
attachment in accordance with 10CFR2.201. This completes GSU's
response to the Notice of Violation.
Sincerely,
J. C. Deddens
Senior Vice President
River Bend Nuclear Group
Attachment
cc Mr. Robert D. Martin, Regional Administrator
U.S. Nuclear Regulatory Commission
Region IV
611 Ryan Plaza Drive, Suite 1000
Arlington, TX 76011 9 %,
NRC Resident Inspector Qy
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SDLTE & IDUISIANPL
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PARISH T MEST PELICIANA
In the Matter of * Docket Nos. 50-458
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GUW SDLTES UTILITIES CG@ANY
(River Bend Station,
Unit 1)
AFFIDAVIT
J. C. Deddens, being duly sworn, states that he is a Senior Vice
President of Gulf States Utilities Ccanpany; that he is authorized on the
part of said Campany to sign and file with the Nuclear Regulatory
Cm mission the documents attached hereto; and that all such documents
are true and correct to the best of his knowledge, information and
belief.
/ W
J. f Deddens
Subscribed and sworn to before me, a Notary Public in and for the
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State and and Parish above named, thish.b day ob(lllOf1(,19h.
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Notary Public in and for
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My Camission is for Life.
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RESPONSE TO NOTICE OF VIOLATION
50-458/8636-01
REFERENCE
Notice of Violation - Robert D. Martin Letter to W. J. Cahill,
Jr., dated December 29, 1986.
FAILURE TO MEET THE REQUIREMENTS OF 10CFR50.59
Air flow problems in the control building had been causing
numerous control building air-conditioning (HVC) and chilled
water (HVK) system transfers. Temporary Alteration (TempAlt)
85-HVK-026 of October 29, 1985 and Prompt Modification Request
(PMR) 86-0038 of June 27, 1986 were installed to mitigate these
transfers. The Unreviewed Safety Question Determinations (USQD) r
for the temporary alteration did not address all possible
consequences of this change with respect to FSAR Section
9.2.10.5. The potential effects of this change were realized
during further engineering review of the design to clear the
plant of TempAlts.
In the original design, starting the control building chilled
water system (HVK) pump A(B) would cause standby service water
(SWP) Pump A(B) and C (D) , HVK chiller A(B), control room air
handling unit (AHU) A(B), switchgear room AHU A(B) and chiller
room AHU A(B) to start. To automatically start the opposite
division, the HVK pumps trip on low air flow in any one of the
three AHU's (or loss of the running chiller) in that division
thereby causing low HVK water flow. HVK pump A (B) would
automatically start on low water flow in the opposite division.
As the plant was configured under the TempAlt and PMR, under
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certain conditions manual action would be required to mitigate
the consequences of a single failure in the system. Under normal
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operation with Division I, Train 'A' HVK pump would not trip an
on a
,
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LOCA signal concurrent with off-site power available and air
, handling unit failure. Since 'A' train HVK water flow is
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maintained, Train 'B' would not automatically start. Operator
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action would be required to maintain area temperature. The other
' division of air-conditioning could be manually started, however, j no analyses had been performed which assumed manual action after
initiation of the event. This condition may have increased the
consequences of an air handling unit failure as previously
evaluated in the safety analysis. Further analysis should have
been completed prior to the change to determine that it was not
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an Unreviewed Safety Question.
f REASON FOR THE VIOLATION l
In the original plant design, as described in FSAR section
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9.2.10.5, low air flow through any control building air handling
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unit or a trip of the running chilled water compressor would trip
the associated chilled water recirculation pump. This causes a
low water flow condition which would automatically start the
other division of control building chilled water / air
conditioning. The control building environment safety analyses
assumes automatic operation of this system following a loss of
coolant event with or without offsite power available.
In the original USOD for the temporary alteration, it was
believed that the low AHU air flow pump trip was only necessary
to protect the chilled water compressors from heat load
transients. Since the compressors have their own low load
protection circuitry and air flow problems were causing spurious
pump trips, TempAlt 85-HVK-026 was written to defeat these pump
trips on pumps A and B. PMR 86-0038 was written to defeat the
trips on the C and D pumps. The unreviewed safety question
determination (USQD) review was performed relying on the previous
evaluation performed for the temporary alteration and did not
identify all of the bases for the trip. Without this pump trip
feature, automatic operation of this system could not occur as
analyzed in a scenario of a loss of coolant event with offsite
power available and failure of a control building
air-conditioning system air handling unit. The consequences of
this scenario were not analyzed prior to the change.
An evaluation was performed to determine the extent of the
problem and the root cause. The extent of the problem was found
to be confined to the cases identified above. Specifically, an
independent review and unreviewed safety question determination
was redone for all open Quality Assurance (QA) Program applicable
temporary alterations and prompt modification requests. No l
additional inadequate USQD's were found. l
The cause of this event has been determined to be failure to
review all the design bases of a system during the engineering of
the temporary alteration and prompt modification request to that
system. The root cause is inadequate training and procedures for
unreviewed safety question determinations. The evaluation
identified a need to strengthen requirements for independent
reviews by prohibiting reviews by telephone and requiring that ,
independent reviewers be knowledgeable in the engineering I
discipline involved. ,
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CORRECTIVE STEPS WHICH HAVE TAKEN AND THE RESULTS ACHIEVED j
TempAlt 85-HVK-026 and PMR 86-0038 were both promptly removed on
October 16, 1986 after it was determined that an Unreviewed
Safety Question may exist. It addition, calculations were then
prepared which show that room temperatures would not have
exceeded the design bases during the above described scenario
assuming manual actuation of the system in 20 minutes. Air
handling unit failure and associated damper loss of power or trip
alarms are provided for each of the major areas served by the
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Control Building Air Conditioning System (i.e., the Control Room,
Switchgear Room and Chiller Rooms). In addition, the Control
Room is continuously manned and it is expected that personnel
would notice any significant rise in temperature and compensate
for any failure; the switchgear room air handling unit discharge
temperature is alarmed in the control room; and since the Chiller
Room does not have any associated dampers, the only credible
failure is the AHU, which is alarmed. Therefore, the
modifications have been determined to have had no impact on plant
safety.
CORRECTIVE STEPS WHICH WILL BE TAKEN TO AVOID FURTHER VIOLATIONS
The remaining QA Program applicable TempAlts installed in River
Bend Station have been either removed or the design and USOD have
been independently reviewed under the current design control
procedures. Also, an independent review has been conducted on
Quality Assurance Program applicable PMR's to assure adequate
USOD's were performed.
Corrective action to prevent recurrence included training and
procedure improvement. The temporary alteration procedure is no
longer in use at River Bend Station. Therefore, action to
prevent recurrence is applicable only to the Prompt Modification
Request procedure.
Training has been provided to all engineering personnel to
reinforce the need for careful design and unreviewed safety
question determinations regardless of schedule pressures. This
training emphasized the need to consider the design basis in
addition to the technical specifications. Procedural
requirements were revised to ctrengthen the requirements for
independent reviews. Additional training on unreviewed safety
question determinations has been provided to the Facility Review
Committou.
To prevent recurrence, engineering personnel who have not had
training in performing USOD's are not allcwed to do so. Similar
training for performing USOD's has been provided to the Facility
Review Committee members and alternates. Additionally retraining
in the performance of USOD's will be provided to the Engineering
Staff and to the FRC on an annual basis. Further, procedural
enhancements are being considered which could provide additional
information to assist engineers in performing USOD's. Also,
procedures for design review have been revised to require on-site
independent reviews by individuals who are knowledgeable in the
area of concern.
In addition, GSU has verified that plant alarm response
procedures currently require plant operators to start the
redundant division of the control building ventilation system
upon receipt of an indication that the running division has
tripped.
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DATE WHEN FULL COMPLIANCE WILL BE ACHIEVED
River Bend Station is currently in full compliance.
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