ML20065H776
| ML20065H776 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 09/28/1982 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NCR-1725, NRC-1725, NUDOCS 8210050249 | |
| Download: ML20065H776 (5) | |
Text
-~
TENNESSEE VALLEY AUTHORITY CH ATTANOOGA TENNESSEE 37401 400 Chestnut Street Tower II cn September 28, 1982 m
s i; r
BLRD-50-438/82-27 h3 BLRD-50-439/82-24 SE!
go
-m 2n onr 4:
un?
c:,
U.S. Nuclear Regulatory Ccamission 1g Region II E..
o Attn:
Mc. James P. O'Reilly, Regional Administrator 101 Marietta Street,. Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
BFJNONTE NUCLEAR PLANT UNITS 1 AND 2 - INSOLUBLS GLUE USED FOR PURGE DAMS IN STAINLESS STEEL PIPING - BLRD-50-438/82-27, BLRD-50-439/8E FINAL REPORT The subject deficiency was initially reported to NRC-01E Impector R. Y. Crlenjak on March 22, 1982 in accordance with 10 CFR 50.55(e) as NCR 1725. This was followed by our interim reports dated April 22 and' June 18, 1982. As discussed with Mr. Crlenjak by telephone on September _10,1982, our final response was delayed. Enclosed is our final report.
If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, ger Nuclear Licensing Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555
\\
0210050249 020920 W&ghA
[^
fs v/
4, o m,o, -,emi,, m.
a ENCLOSURE f
Bl!LLEFONTE NUCLEAR PLANT UNITS 1 AND 2 INSOLUBLE GLUE'USED FOR PURGE DAMS IN STAINLESS STEEL PIPING NCR 1725 BLRD-50-438/82-27,.BLRD-50-439/82-24 E
10 CPR 50.55(e)
FINAL REPORT
{
i
[
Description of Deficiency I
Some glue used in installation of purge, dams in stainless steel piping
-l appeared-insoluble during flushing activities, and minor glue residual l
remains in piping at purge dam locations. This problem was anticipated
(
.during the m solution of nonconformance report (NCR) 835. The disposition of NCR 835 directed discontinuing the use of Elmers Glue-All and f
reconstended using Elmers School Glue. The insoluble glue residual has been i
identified as Elmers Glue-All used before NCR 835 and Elmers School Glue that has been affected by heat from welding activities. When purge dans f
f are located too close to the welds, the currently used and normally soluble Elmers School Glue will char and become much less soluble.
Safety Implications i
It has been determined through tests and analyses described below that no
+
condition adverse to the safe operation of the plant exists. This v
f conclusion is based on the following observations:
l l
[
- 1) The purge dans will not cause stress corrosion cracking of the pipe.
l
- 2) Very little purge dam residual maains on the pipe wall after preoperational flushing. The residual remaining will all dissolve 4
during plant operation. Solubilized purge dam material'is not harmful
}
to the systems. Any particles that may break loose before dissolution is complete will not obstruct any piping or instrument lines.
Corrective Action f
Based on the attached supporting information, TVA has concluded that glue residual left in piping systems will not cause a safety problem.
l Laboratory tests have shown that even the glue that was initially thought to be insoluble will dissolve. Flushing of systems thus far has shown that demineralized water flushing can achieve removal of enough of the purge ' dam l
i; residue so.that the possibility of large pieces breaking loose is highly
'unlikely. TVA will: mvise the acceptrace criteria for proof' flushing particulates to allow purge das particles up to 1/8 inch in any dimension.
i This avision will be accomplished by November 8,1982.
i i
In addition, purge dam residual on the pipe wall will be acceptable provided that the system has met the proof-flush acceptance criteria. The-reactor coolant pump seal water injectiert.line in the Makeup and Purifica-i i
tion System will be flushed with acetic acid to remove as saach of the purge j
i das maidue as possible. This will be accomplished by October 15, 1.983 l
l TVA has revised the welding specifications to ensure that purge dams are
- )
placed far enough from-the weld to prevent charring of the glue. TVA has l
I
=also increased welder.apareness that substitution of the specified Elmers 1
l
{'
. School Glue is not permitted. No other TVA nuclear plants are affected by' l
this problem.
' ~
g
.f g
4.
.e,.--
- u. +.
J a. - -
.+w
~
,.,n...,
.,,-,-,-...v..
.,,,--..,.--nv-
.,,-.v.----.-.
]
,, c ATTACIDENT 4
SUPPORTING INFORMATION FOR NCR 1725 1
Metallurgical Testing
-Metallurgical testing and chemical analysis has shown that residual
[
purge dan materials remaining in contact'with 304 stainless steel will (have no detrimental effects on the piping material during operation of j
j the plant.
The Dissolvo Water soluble purge paper (WLD-60) contributes virtually i
l all of the halides present in the purge dam residue. Specific ion l
tests have shown leachable chlorides in the range of 170-200 parts per
.. 3
- million.
9 Tests show that purge das materials closer than 3/g F.
inch from the edge of a weld reach a temperature of approximately 600 At this
(
temperature the material carbonizes to the extent that it flakes off l
auch the same as food in a self-cleaning oysn, and subsequent flushes
~
remove the flaking material.
l Two potential modes of cracking have been addressed:
t 1
1.
Stress Corrosion Cracking (SCC)
The purge dam residue is a minimum of 3/4-inch from the edge of the weld. This is beyond the distance at which residual stresses
[
from welding are present. In the absence of tensile stress, SCC
~
does not occur.
?,
t 2.
Intergranular Stress Corrosion Cracking (IGSCC)
L The heat affected zone (HAZ) of the weld extends to a ' maximum of.
approximately 3/16-inch from the edge of the welds. As stated I
previously, the purge dans are located a minimum of 3/4-inch fros' i
l the weld and, therefore, the potentially aggressive environment is 4
not present in the HAZ.
i Additional testa performed at TVA Singleton Laboratory determined that I
no harmful effects should be expected even if the purge das materials
[
were left in contact with the base material. Samples of glue with!
addedchloride.legelsofoveg1000ppawerebaked'onpipesamplesand 4
autoclaved at 150 F and 550. F.in borated water. After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> j
virtually all chlorides were leached from the glue at both temperatures. The 304 stainless base materials were. subsequently examined microscopically for corrosive effects.
l After 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> of exposure there was no apparent attack. Because i
' virtua11y 'all chlorides leach out of the glue ' atter '.24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of l
~
' exposure, TVA anticipates no adverse effects from the ' relatively l
[
small amount of material remaining.
i s.-
i
_'C:y;p i
4 N.h
)
uA m_.-..._.
.. ~
. ~. - _.. - _.,
.., -,, _ _.. ~..
-..-,.,_.c
Attachment-
[
Page 2 f
h
.TVA can anticipate no harmful effects on the ' stainless steel pipe as a I
result of purge dat: residuals remaining in contact with the stainless i
steel pipe during system operation.
i
^
' Acetic Acid Testing and Firshing Laboratory testirg was performed to determine what solvents are
[
available that could be used to remove the glue from the pipe.
l Testing showed that acetic acid was the most promising solvent.
Acetic acid aided in the removal of the noncharred glue; however, it 3,
did not have an appreciabla effect en the charred glue.. The second c[
intarim report on NCR 1725 stated that acetic acid would be tried out j
i' on a system thkt had not been previously flushed. Since there were'no l
systems available that had not been fluahed, the trial was run on the O
Reactor Building Spray System (with the exception of the spray headers and the sodium hydroxide tank and piping).
l t
The Reactor Building Spray Syste:s had been previously flushed with l
l water, but removal of a flanged spool piece revealed noncharred purge
[
dam residual en the pipe wall. Thas the pipe interior could be visually inspected before and after the acetic acid flush. The system was flushed with 5 pergent acetic acid for approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at 4
temperatures up to 145 F.
Inspection of the piping after the acetic acid flush showed that most of the purge das residuals had been i
i removed from the pipe wall.
[
{
j Autoclave Tests f
i Autoclave testing was performed to determine what effect high temperature water will have on charred glue since it is the most 1
insoluble. Stainless steel coupons were prepared using both Elmers
[
Glug F and 500AllandEgnersSchoolGlue. Coupons were baked in an oven at t
q'
-400 F to simulate purge dans that were placed too close to the welds. Half of the coupons representing all of the above
[
conditions were soaked in acetic acid to simulate acetic acid flushing
'[
of the piping systems.
[
4 L
The coupons were placed in the autoclave which contained borated water
.I The
[
representative of reactor coogant.F to 500, autoclave was operated at F to identify temperature temperatures ranging from 200 4.
_ effects on the glue. The test results show that the charred glue will l
~
l dissolve, and that the autoclave temperature is the only variable ghat has an effect en the dissolution rete of the charred glue. At 200,F, about 6 percent of the charred glue dissolved in 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br />. gt300 F,
.?
19 percent of the charred glue dissolved in 78 hours9.027778e-4 days <br />0.0217 hours <br />1.289683e-4 weeks <br />2.9679e-5 months <br />; at 400 percent.of the charred glue dissolved in 51 hours5.902778e-4 days <br />0.0142 hours <br />8.43254e-5 weeks <br />1.94055e-5 months <br />; and at 500,F, 84 F, over 93 percent of the charred glue dissolved in 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br />.
l e
i These results show that given enough time, the glue deposits will f
f eventually. dissolve. The results also'show that any glue particles i
t that get into tp reactor will dissolve in the reactor, since it operates at 600 F.
m
,: =
=
(
yY
{
l [1 l
R i
-s. :. w. a _. ~m ~,. - --
~
~
_.,.._.m._
...--_,_,,,,-......---,s.
, ~, + - - - - -,
~
Attachment Page 3 Demineralized Water Flushing Several systems have been fluched with demineralized water to date.
These it.clude the Spent Fuel Cooling and the Reactor Building Spray Systems. Three flew paths on the Spent Fuel Cooling System were flushed with unheated derJiceralizer ulter. Cna flow path could not meet the acceptance criteria of 1/32-inch by 1/16-inch particle size.
However, the particleg were less than 1/8-inch. The flow path was then flushed with 180 F water. After f,he hot water flush, the acceptance criteria could still not be met, even though the particles being detected were still less than 1/8-inch.. Spool pieces were removed so that the pipe interior could be visually examined. Reactor building spray train B was also flushed with cold demineralized water before the acetic acid flush. The path was flushed to the 1/32-inch 1/16 inch particulate acceptance criteria with demineralized water.
Inspection of the pipe interior after the flush showed some noncharred purge dam glue ridges in the pipe. Flushing of these and other flow paths has demonstrated that the systems can be flushed to a point where only tightly adherent glue ridges are left in the pipe and that only small particles break loose from these ridges during system operation.
Safety Analysis of Particulates All of the systems were analyzed with respect to problems which could be caused by particulates breaking loose from purge dam residuals during plant operation. The analysis was based on the assumption that glue particles up to 1/8-inch could be present in the operating systems. Based on this analysis, plant safety will not be compromised with glue particles up to 1/8-inch present in the Waste Disposal (WD),
Chemical Addition and Boron Recovery (CA&BR), Reactor Building Spray (RBS), Core Flooding (CF), Decay Heat Removal (DHR), Spent Ft.al Pool Cooling and Cleanup (SFPCC), and Makeup and Purification (MU&P)
Systems. Pumps in the RBS, DHR, SFPCC and MU&P Systems are equipped with cyclone separators in the seal water supply so that particles in the seal water would be removed before getting to the pump seals. The water in instrument sense lines is stagnant; therefore, it is highly, unlikely that purge das particles could find their way into instrument lines or cause, problems.
4 9
(W e ae s4 4
Sp h4C.,
'h93 > N-4 A.sh.dD # N SWP-PO-O MY e.
m-,-
.-m
=+
-w-
---p