ML17262A577
| ML17262A577 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 06/20/1991 |
| From: | Carrasco J, Gray E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML17262A576 | List: |
| References | |
| 50-244-91-13, NUDOCS 9108140069 | |
| Download: ML17262A577 (10) | |
See also: IR 05000244/1991013
Text
'
U. S. NUCLEAR REGULATORY COMMISSION
REGION I
Report No.
50-244/91'-13
Docket No.
50-244
License No. DRP-18
Licensee:
Rochester
Gas and Electric Corporation
49 East Avenue
Rochester, New York 14649
Facility Name:
R. E. Ginna Nuclear Plant
Inspection At; Ontario, New York
Inspection Conducted;
-24,
gg~ .c~~-
J..
co, Materials Section,
Engineering Branch, DRS
Approved by:
E. H. Gray, Chief,
aterials Section,
Engineering Branch, DRS
Date
g/go AI
Date
Inspection Summary:
Inspection on May 20-24, 1991 (Report No. 50-244/91-13)
Areas Inspected:
The engineering disposition for the over-elongated
stud of the manway,
Steam Generator "A" cold leg was reviewed.
The Advanced Digital Feedwater Control System (ADFCS) design/installation,
and
operational test was reviewed.
Results:
No violations or deviations were identified.
However, the inspector noted that
surface examination by PT or MT is usually not performed on the S/G's manway cover studs
before their reuse.
910814008<9
910730
ADOCK 05000244
6
QET~I
1.0
er on
ntacted
Rochester
a
and Electric
ration
- R. Mecredy
- P. Wilkens
- C. Forkell
- L. Rochino
- D. Baker
- R. Carter
- G. Voci
- J. Dunne
- N. Oliva
- B. Bryan
- T. Marlow
- T. Harding
- S. Adams
- J. Widay
T. Wieand
L. Dipzinski
G. Croney
J. Martin
Vice-President Ginna Nuclear Production
Department Manager Nuclear Engineering Services
Manager of Electrical Engineering
Lead Mechanical Engineer
Lead Electrical Engineer
Mechanical Engineer
Manager of Mechanical Engineering
Mechanical Engineer
Electrical Engineer
Liaison Engineer-EWR 4773
Superintendent-Support
Services
Modification Support Coordinator
Technical Manager
Superintendent-Production
Construction Engineer
Construction Engineer
Consultant
Corrective Action
- denotes
those who attended the exit meeting
2.0
Review of the En ineerin
Di
ition f r None nf rmance Re ort NCR
1-2 8
~Back round
Each of the two steam generators
(S/Gs) at R. E. Ginna Station have hot and cold leg
manways for access
to the inlet and outlet plenums for maintenance
and inspection
purposes.
Each manway has a cover which is installed against the S/G as a flange
bolted connection.
These bolted connections are essential for maintaining the integrity
of the pressure boundary of the Reactor Coolant System (RCS).
Therefore, it is
necessary
to apply a closing force greater than the loads caused by static water head
and steam pressure during operation.
Each manway closure consists of a flexitallic gasket,
a stainless steel insert plate, a
carbon steel cover plate and sixteen 1-7/8" studs, flat washers and nuts.
All the
sixteen manway closure studs are tensioned simultaneously using an EGB.G tensioner
mechanism which contains annular type hydraulic jacks around each of the sixteen
studs, and provides for sequential tightening of the stud nuts.
Event
h
Tri
r
h
Pre
i n fN R
1-2
During the tensioning of the manway studs in S/G "A" cold leg at the end of the 1991
outage, the licensee observed that fifteen of the sixteen studs were outside the
specified elongation range of 7.0 to 10.6 mils. Subsequently,
all studs outside this
range were successfully adjusted to be within the range using provisions of the
approved tensioning procedure, except for stud ¹5, which exhibited a final elongation
of about 12 mils. The licensee concluded that interference between the pistons and
mechanical stops had prevented uniform stud extension during tensioning.
Consequently,
the closure was disassembled;
stud ¹5 was replaced,
and a new
flexitallicgasket was installed.
The. licensee reassembled
the closure and established
tension of the studs'in accordance
with the approved procedure.
All measured
stud elongations were within the
allowable range after tensioning except for stud ¹8, which had an average measured
elongation of 18.5 mils which is about twice the allowable.
At this point the licensee
originated NCR ¹91-268, for the disposition of stud ¹8.
'eview of the Technical Basi
for the En ineerin
Dis osition of NCR
1-268
The licensee's disposition for NCR ¹91-268 as "Use as is" was based on the technical
.
evaluation prepared by Dominion Engineering, Inc., of Mclean, Virginia.
The inspector reviewed the technical evaluation including the finite element analysis,
also prepared by Dominion Engineering, Inc.
This technical evaluation consists of
two analyses,
the first was a probable cause of measured
over-elongation of stud ¹8,
and the second was to determine the effect of operating with stud ¹8 failed.
Based on Dominion Engineering's report; the licensee concluded that the probable
cause of the elongation of stud ¹8 was plastic deformation of the upper (non-load
.
carrying) part of the stud as a result of misalignment between the piston and the
reaction nut, during the final attempt at tensioning.
Angular misalignment between the piston and reaction nut can produce high bending
stresses
in the reduced diameter upper (non-load carrying) part of the stud which can
'ause the maximum stress in the portion of the stud to exceed yield, and the stud to
elongate.
The inspector agreed with this finding based on visual observation of the S/G mock-
up, the studs, and the tensioning ring.
'
The inspector inquired about the validity of the coefficients of friction of 0.5 used as
an upper boundary in the analysis to determine the effect of friction between the
manway cover and the S/G shell flange on the stress developed in the studs during
heatup.
The licensee contacted Dominion Engineering, Inc., who stated that @=0.5 is
a reasonable value.
To support this statement, Dominion Engineering referenced
the
Standard Handbook of Lubrication Engineering, McGraw-Hill, New York, NY, 1968
edition.
In this reference,
a range of friction coefficients for clean unlubricated
surfaces was given as 0.3 to 0.5.
The inspector found this answer acceptable.
The inspector asked the licensee ifany surface examination such as magnetic particle
(MT) or penetrant test (PT) was performed for the studs before their mounting, the
licensee indicated that no MT-or PT was performed on these studs and added that
according to their established Quality Assurance manual for S/G bolts, studs and nuts
of two inches in diameter or less only visual examination is required.
The inspector
verified this statement on page 48 of the licensee's quality assurance
manual.
Action
item 2 of the IEB 82-02 required inspection of closure fasteners (manway studs) by
visual and surface examination gWA 2210 and 2220) prior to reuse.
The licensee
stated that they would review inspection practices of primary side fasteners where
these are to be reused.
In conclusion, the inspector found the technical evaluation prepared by Dominion
Engineering, Inc., acceptable.
Therefore, the disposition for NCR 91-268 of "use as
is," is adequate,
since stud ¹8 remained functional and capable of carrying the load.
3.0
Advanced Di ital Feedwater
ontrol S stem
ADF
S
Inspection of the ADFCS was initiated during Inspection No. 50-244/90-29,
conducted on November 26-30, 1990.
Inspection 90-29 was performed to review the
conceptual design, preliminary drawings, engineering specifications,
and installation
procedures affecting the modification.
3.1
co e of the Present In
ection
The inspector reviewed the seismic analysis of the main control board (MCB)
to ensure that the structural integrity of the MCB is not compromised by the
changes which were required by the modification.
The inspector also reviewed
the mechanical design and installation of the new S/G wide range level
transmitters,
associated
sensing lines, and instrument valves.
In addition, the
category I instrumentation sensing lines for the valves associated
with the new
main steam flow transmitters were included in the present inspection.
The
inspector witnessed the startup testing of the new installed system.
3.2
~Fin i~in
The inspector reviewed the seismic evaluation of the main control panel
(control room) and found it acceptable.
The inspector discussed
the
verification of a computer program used by URS/John A. Blume & Associates,
the contractor, in the seismic reevaluation of the Main Control Board.
This computer program named "FSC" was used to generate floor response
.spectra directly from input ground spectra.
The licensee's contractor showed
evidence that this computer program was verified in accordance with
established quality assurance
procedures.
The inspector found this computer
program verification acceptable.
3,3
Review of the Desi
n Anal sis of the Tubin
for the ADFCS
M
ifi
i n EWR 4773
The inspector reviewed the technical basis for determining generic span
lengths, offsets and support loads for various instruments and a sample tubing
design layout for the modification.
Licensee document titled, "Design Analysis
Ginna Station Generic Design Qualification of Tubing," clearly outlines the
analysis used to qualify spans for instrument and sample tubing lines to ANSI
B31.1Property "ANSI code" (as page type) with input value "ANSI</br></br>B31.1" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process., "Power Piping," 1973 Edition with addenda thru Summer 1973 code.
This analysis used simple beam equations found in the manual of steel
construction to determine maximum tubing spans for deadweight, pressure and
seismic loading conditions along with the offset lengths required to satisfy
thermal expansion and anchor displacements.
Fortran computer program Version 2.0 was used for this analysis to organize
the results in a tabular format.
The inspector found this tabulation easy to
follow and readily useable for the design of safety-related tubing.
These
tabulations enable the license to design safety related tubing without performing
detailed individual calculations.
In conclusion, the inspector found the generic design qualification of tubing
acceptable for this modification.
'
3.4
tartu
Testin
f the ADF
Startup testing of the newly installed ADFCS included four tests to be
performed during power ascension to ensure the proper operation and setpoint
adjustment of the ADFCS. Four types of testing and data acquisition were
performed:
Open loop (manual), closed loop (automatic), monitoring of
normal plant startup transient operations,
and data acquisition under steady-
state or quasi-steady-state
conditions.
The inspector observed a portion of the test in progress,
and interviewed the
contractor and the Westinghouse engineer. The test was conducted in
accordance
to procedure No. SM-4773.30, titled, "Advanced Digital
Feedwater'ontrol
System Startup Test Procedure".
No problems were detected and the
system successfully performed during the test.
In conclusion, the ADFCS modification had a firm technical basis and was
done in accordance with written procedures.
The licensee has displayed a solid
technical ability as well as good project management skills in the performance
of this task.
The inspector met with licensee representatives
(see paragraph
1) at the end of the
inspection on May 24, 1991.
The inspector summarized the purpose and scope of the
inspection and identified the inspection findings.
Cl'