Information Notice 1996-64, Modifications to Containment Blowout Panels Without Appropriate Design Controls
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UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001
December 10, 1996
NRC INFORMATION NOTICE 96-64: MODIFICATIONS TO CONTAINMENT BLOWOUT
PANELS WITHOUT APPROPRIATE DESIGN
CONTROLS
Addressees
All holders of operating licenses or construction permits for nuclear power
reactors.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice to alert
addressees to the potential for operating outside of the design basis as a result of modifying
structures without appropriate design controls. It is expected that recipients will review the
information for applicability to their facilities and consider actions, as appropriate, to avoid
similar problems. However, suggestions contained in this information notice are not NRC
requirements; therefore, no specific action or written response is required.
Description of Circumstances
North Anna, Units 1 & 2 On February 13, 1996, it was identified that six blowout panels for both units' incore
instrument tunnels had been modified by installing hasps and locks without appropriate
design controls. Additionally, several steam generator and reactor coolant loop containment
cubicle door panels had been modified by tack welding their sheet metal covers to the door
frames and adding stiffener plates around the door handles. These modifications were not
reviewed prior to installation to assure their compliance with design bases assumptions
contained in the Updated Final Safety Analysis Report (UFSAR), and existed for an extended
time period during past operating cycles.
Cooper
On November 21, 1995, it was recognized that the accident analysis for High Energy Line
Break outside Primary Containment contained a key assumption that had been rendered
invalid. For a postulated High Energy Line Break inside the Reactor Building Main Steam
Tunnel (Steam Tunnel), the Steam Tunnel blowout panels had been credited with rupturing to
allow a vent path to the Turbine Building, thereby preventing compartment overpressurization.
In an effort to reduce Secondary Containment leakage, maintenance was performed on the
DfP
blowout panels in 1985 to cover them with fiberglass. As a result, the blowout panels would
rupture at a higher pressure than credited in the High Energy Line Break analysis. This was
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IN 96-64 December 10, 1996 apparently attributable to an inadequate investigation of the blowout panels' design basis
functions prior to the initiation of the maintenance.
Quad Cities
On May 10, 1996, a tornado caused structural damage to the metal siding that forms the
secondary containment barrier for the refueling floors on both Units. Subsequent
documented inspections revealed approximately 270 (out of 1496) damaged explosion bolts.
It was observed that not all of the damaged bolts were a result of this tornado. On
August 23, 1996, it was concluded, through calculations, that not all of the design
requirements for the siding would have been met and this would have placed secondary
containment In an inoperable condition. The previously damaged explosion bolts were
damaged by either a pressure load or by ineffective work practices.
Nine Mile Point, Unit 1
On October 25, 1993, i was determined that the relief (blowout) panels in the Nine Mile Point
Unit I turbine and reactor buildings would not blow out at the design pressure of 2.15 kph
(45 lbfft2) because the bolt fasteners for the panels were larger than designed and had a
higher ultimate strength than designed. The initial engineering evaluation of this condition
erroneously determined that the turbine and reactor building panels would blow out at
2.87 kph (60 VIWf
2) and 2.54 kph (53 VbWt2), respectively, to relieve internal building pressure
prior to structural failure of the buildings, and the panels were declared operable. On
March 27, 1995, i was determined that there was an error in the design assumptions for load
distribution. Revised calculations confirmed that the relief panels would not blow out until the
internal building pressure exceeded the minimum documented building structural design of
3.83 kph (80 VIW 2). The cause of this event was inadequate quality control measures during
initial construction which resulted in oversize bolts being installed in the relief panels.
Discussion
The purpose of blowout panels is to prevent overpressure or overtemperature conditions in a
compartment or other enclosure that could be structurally damaged due to a high energy line
break inside the compartment, or that contains equipment that would be damaged by the
overpressure or overtemperature condition. This function may or may not be a "safety- related" function depending on whether the high energy line break could result in loss of (1)
the capability to reach and maintain safe shutdown, or (2) the capability to mitigate an
accident in which a high energy line break is postulated to occur as a passive or
consequential additional failure. In addition to the overpressure "active" function, blowout
panels may also have a passive function such as tornado missile protection.
Blowout panels are designed to open at specific design differential pressures. Licensees
discovered that as-found configurations either would not allow the panels to open until after
exceeding the design pressure, or in the Quad Cities example, did not meet all of secondary
containment design bases described in the UFSAR. Modifications made to satisfy apparently
valid concerns did not adequately evaluate the effects on the panels' design bases or
IN 96-64 December 10, 1996 adequately consider the design assumptions used for analyzing containment structures and
supports. The modifications were not recognized as having the potential to place the
structures outside of their design bases.
Previous Similar Generic Communication
NRC Information Notice 96-17, "Reactor Operations Inconsistent with the Updated Final
Safety Analysis Report," dated March 18, 1996, (Accession No. 9603150213).
This information notice requires no written response. If you have any questions about the
information in this notice, please contact the technical contacts listed below or the appropriate
Office of Nuclear Reactor Regulation Project Manager.
References
1.
NRC Inspection Report 50-338/96-01 & 501339/96-01, dated March 21, 1996, (Accession Number 9604090115)
2.
Cooper Nuclear Station Licensee Event Report 50-298/95-018-01, dated
May 31, 1996, (Accession Number 9606110378)
3.
Quad Cities Nuclear Power Station Licensee Event Report 50-254 &
50-265/96-016, dated September 20, 1996, (Accession Number 9609300009)
4.
Nine Mile Point Nuclear Station Unit 1 Licensee Event Report 50-220195-005-01, dated June 26, 1996, (Accession Number 9607010370)
Ž r Thomas T. Martin, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts: Donald R. Taylor, RHI
(540) 984-5421 E-mail: drt@nrc.gov
Neal K. Hunemuller, NRR
(301) 415-1152 E-mail: nkh@nrc.gov
Attachment: List of Recently Issued Information Notices
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Attachment
December 10, 1996 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to
96-63
96-62
96-61
Potential Safety Issue
Regarding the Shipment
of Fissile Material
Potential Failure of the
Instantaneous Trip Function
of General Electric RMS-9 Programmers
Failure of a Main Steam Safety
Valve to Reseat Caused by an
Improperly Installed Release
Nut
Potential Common-Mode Post-
Accident Failure of Residual
Heat Removal Heat Exchangers
Potential Degradation of
Post Loss-of-Coolant
Recirculation Capability
as a Result of Debris
RCP Seal Replacement with
Pump on Backseat
12/05/96
11/20/96
11/20/96
11/14/96
10/30/96
10/30/96
All U.S. Nuclear
Regulatory Commission
licensees authorized
to possess special
nuclear material in
unsealed quantities
greater than a critical
mass
All holders of OLs
and CPs for nuclear
power plants
All holders of OLs or
CPs for nuclear power
reactors
All holders of OLs or
CPs for nuclear power
reactors
All holders of OLs or
CPs for nuclear power
reactors
All holders of OLs or
CPs for pressurized-water
reactors
96-60
96-59
96-58 OL = Operating License
CP = Construction Permit
-
K'
December 10, 1996 adequately consider the design assumptions used for analyzing containment structures and
supports. The modifications were not recognized as having the potential to place the
structures outside of their design bases.
Previous Similar Generic Communication
NRC Information Notice 96-17, "Reactor Operations Inconsistent with the Updated Final
Safety Analysis Report," dated March 18, 1996, (Accession No. 9603150213).
This information notice requires no written response. If you have any questions about the
information in this notice, please contact the technical contacts listed below or the appropriate
Office of Nuclear Reactor Regulation Project Manager.
References
1.
NRC Inspection Report 50-338/96-01 & 50/339/96-01, dated March 21, 1996, (Accession Number 9604090115)
2.
Cooper Nuclear Station Licensee Event Report 50-298/95-018-01, dated
May 31, 1996, (Accession Number 9606110378)
3.
Quad Cities Nuclear Power Station Licensee Event Report 50-254 &
50-265/96-016, dated September 20, 1996, (Accession Number 9609300009)
4.
Nine Mile Point Nuclear Station Unit 1 Licensee Event Report 50-220/95-005-01, dated June 26, 1996, (Accession Number 9607010370)
original signed by D.B. Matthews
hLhomas T. Martin, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts: Donald R. Taylor, RII
(540) 984-5421 E-mail: drt@nrc.gov
Neal K. Hunemuller, NRR
(301) 415-1152 E-mail: nkhenrc.gov
Attachment: List of Recently Issued Information Notices
Tech Editor has reviewed and concurred on
DOCUMENT NAME: 96-64.IN
- See previous concurrence
To receive a copy of this document, Indicate In the box: "C" a Copy without enclosures "EN'
E
Copy wqtpcdures "N" - No copy
OFFICE
PECB
C:SCSB
C:PECB
D:DRP9 O/1 I
NAME
INHunemuller
CBerlinger
AChaffee*
TMartW f I
DATE
12/
/96
11/18/96
11/22/96
12/ /96
OFFICIAL RECORD COPY
K-,
IN 96-xx
November xx, 1996 adequately consider the design assumptions used for analyzing containment struct
sand
containment structures and supports. The modifications were not recognized a aving the
potential to place the structures outside of their design bases.
Previous Similar Generic Communication
NRC Information Notice 96-17, "Reactor Operations Inconsistenth the Updated Final
Safety Analysis Report," dated March 18, 1996, (Accession N .9603150213).
This information notice requires no written response. If
u have any questions about the
information in this notice, please contact the technical ontacts listed below or the appropriate
Office of Nuclear Reactor Regulation Project Managr.
References
1. NRC Inspection Report 50-338/96-01
0/339/96-01, dated March 21, 1996, (Accession
Number 9604090115)
2. Cooper Nuclear Station License
vent Report 50-298/95-018-01, dated
May 31, 1996, (Accession Num er 9606110378)
3. Quad Cities Nuclear Power tation Licensee Event Report 50-254 &
50-265/96-016, dated Se ember 20, 1996, (Accession Number 9609300009)
4. Nine Mile Point Nule Station Unit 1 Licensee Event Report 50-220/95-005-01, dated
June 26, 1996, (A
sion Number 9607010370)
Thomas T. Martin, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technica contacts: Donald R. Taylor, RII
(540) 984-5421 E-mail: drt@nrc.gov
Neal K. Hunemuller, NRR
(301) 415-1152 E-mail: nkh@nrc.gov
Attachment: List of Recently Issued Information Notices
DOC
ENT NAME: G:INKHXBLWTPNLS.IN
See previous concurren
To rle
a copy of this document, Indicate In the box: "C"
- Copy without enclosures "E" - copy w igsures "N" No copy
OYFICE
PECB
C:SCSB
I
C:PECB
D:DR
r
NAME
NHunemuller
CBerlinger *
AChaffee*
TMartfn 1n!
DATE
11/ /96
11/18/96
11/22/96
/ /96D
OFFICIAL RECORD COPY-
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IN 96-xx
November xx, 1996
Pane% 3 nf R
meet all of the secondary containment design bases described In the UFSA
Modifications made to satisfy apparently valid concerns did not adequa
evaluate
the effects on the panels' design bases or adequately consider the de gn
assumptions used for analyzing containment structures and suppo
. The
modifications were not recognized as having the potential to pia
the structures
outside of their design bases.
Previous Similar Generic Communications
/
NRC Information Notice 96-17, "Reactor Operations
consistent with the Updated Final
Safety Analysis Report," dated March 18, 1996, cession No. 9603150213).
This information notice requires no written r ponse. If you have any questions about
the information in this notice, please con
t the technical contacts listed below or the
appropriate Office of Nuclear Reactor R ulation Project Manager.
References
1.
NRC Inspection Report
i38196-01
& 601339196-01, dated March 21, 1996, (Accession Number 96 090115)
2.
Cooper Nuclear Staon Licensee Event Report 60-298195-018-01, dated
May 31, 1996, (Ac
sslon Number 9606110378)
3.
Quad Cities N lear Power Station Licensee Event Report 50-254 &
60-265196-01 dated September20, 1996, (Accession Number9609300009)
4.
Nine Mile
Iont Nuclear Station Unit I Licensee Event Report 50-220195-005-01, dated Jue 26, 1996, (Accession Number 9607010370)
contacts:
Thomas T. Martin, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Donald R. Taylor, RH
(540) 984-5421 E-mall: drt@nrc.gov
Neal K. Hunemuller, NRR
(301) 415-1152 E-mall: nkh@nrc.gov
Attachment: List of Recently Issued Information Notices
TACt
q4 2 6°
DOCUMENT NAME: G:INKHRBLWTPNLS.IN
- See previous concurrence
To receive a copy of this document, Indicate In the box: "C" = Copy without enclosures wE" - Copy with enclosures "N" n No copy
OFFICE
PECB
J .
C:SCSB
I
C:PECB
D:DRPM l
NAME
NHunemullert
CBerlinger *
AChaffee Ok& ITMartin
DATE
11/L/96
11/18/96
11/L/96
'
11/ /96
OFFICIAL RECORD COPY
v
IN 96-xx
November xx, 1996
for analyzing containment structures and supports: The modifications were not
recognized as having the potential to place the structures outside of their
design bases.
Previous Similar Generic Communications
NRC Information Notice 96-17, "Reactor Operations Inconsistent with
Updated Final Safety Analysis Report," dated March 18, 1996, (Acc
9603150213).
This information notice requires no written response. If y
have
questions about the information in this notice, please cotact the 1 contacts listed below or the appropriate Office of Nuci r Reactor I
Project Manager.
ion No.
any
technical
Regulation
References
1.
NRC Inspection Report 50-338/96-01 & 50/
-01, dated March 21, 1996,
2.
Cooper Nuclear Station Licensee Eve
Report 50-298/95-018-01, dated
May 31. 1996, (Accession Number 96 110378)
3.
Quad Cities Nuclear Power Stati
Licensee Event Report 50-254 &
50-265/96-016, dated September 20, 1996, (Accession Number 9609300009)
4.
Nine Mile Point Nuclear St ion Unit 1 Licensee Event Report 50-220/95-
005-01, dated June 26, 19 , (Accession Number 9607010370)
Thomas T. Martin, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts:
onald R. Taylor. RII
(540) 984-5421 E-mail drt@nrc.gov
Neal K. Hunemuller, NRR
(301) 415-1152 E-mail nkh@nrc.gov
Attachment. ist of Recently Issued Information Notices
DOCUMENT NAME:
- \\NKH\\BLWTPNLS.IN
- See previous concurrence
To ecelve a copy of
Is
document, Indicate In the box: "C" - Copy without encosures "E"
- Copy with enclosures "N"
N
No copy
OFFICE 1PEV
l. 1C:SCSB
C:PECB
D:DRPM
NAME
N nemuller %M
CBerlinger *
AChaffee
TMartin
DATE
1/f?/96
11/18/96
11/
/96
11/
/96
/
Ukt lIAL KtLUKU L Y
A . '4 L
IN 96-xx
- .November
xx. 1996 This information notice requires no written response. If you have any
questions about the information in this notice, please contact the technical
contacts listed below or the appropriate Office of Nuclear Reactor Regulation
Project Manager.
References
1.
NRC Inspection Report 50-338/96-01 & 50/339/96-01. dated March 21. 1996.
2.
Cooper Nuclear Station Licensee Event Report 50-298/95-018-01. dated
May 31. 1996, (Accession Number 9606110378)
3.
Quad Cities Nuclear Power Station Licensee Event Report 50-254 &
50-265/96-016, dated September 20. 1996. (Accession Number 9609300009)
4.
Nine Mile Point Nuclear Station Unit 1 Licensee Event Report 50-220/95-
005-01, dated June 26. 1996. (Accession Number 9607010370)
Thomas T. Martin. Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts:
Donald R. Taylor, RII
(540) 984-5421 E-mail drt@nrc.gov
Neal K. Hunemuller, NRR
(301) 415-1152 E-mail nkh@nrc.gov
Attachment:List of Recently Issued Information Notices
DOCUMENT NAME: G:\\NKH\\BLWTPNLS.IN
To receive a copy of this document, Indicate In tlh-
")
"
Copy without enclosures "En - Copy with enclosures "NW - No copy
(OFFICE
PECB
l
C:SCS6 A
CPECB
l
D:DRPM l
NAME
NHunemullerm/ ' CBerlinger
IAChaffee
MTartin
DATE
11//5/96
111/ 96
&I11/
/96
11/
/96 OFFICIAXL RECORD COPY