NRC Ouestions (9/14/79) O. 1/2
Transcript of NRC Ouestions (9/14/79) O. 1/2
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November 21, 1979
Trojan Nuclear PlantDocket 50-344License NPF-1
Director of Nuclear Reactor RegulationATTN: Mr. A. Schwencer, Chief
Operating Reactors Branch #1Division of Operating Reactors
- U. S. Nuclear Regulatory CommissionWashington, D. C. 20555
Dcar Sir:
Attached are 40 copies of Licensee's responses to several of the NRCStaff questions of September 19, September 28 and October 2,1979.
Sincerely,
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DJB/LWE/4sa6A24Attachments
c: Mr. R. H. Engelken, Directorl'. S Nuclear Regulatc ry Commission |j()q J.;74Region V
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Mr. Lynn Frank, DirectorState of OregonDepartment of Energy \
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NRC Ouestions (9/14/79)
O. 1/2 Page 1 of 2
1. Provide a detailed description of how the equivalent dia-
meter was determined which was used in computing the penetra-
tion of the dropped washer into the steel cover plate for
cable trays.
2. Provide a drawing which illustrates the projected area
used for computing the equivalent diameter.
Answer:
An evaluation of the postulated drop of a plate washer on the
steel cover trays was provided in Licensee's response dated
September 5, 1979 to Systems Branch Question No. 11. In the
equation used, the term "D" is the diameter of the missile .
For an irregularly shaped missile, such as the corner of the
plate washer, an equivalent diameter must be used in the
analysis.
The equivalent diameter is taken as the diameter of a circle
with an area (A) equal to the circumscribed contact area or
projected frontal area of the noncylindrical missile. (Refer-
ence: page 2-4, Bechtel Topical Report BC-TOP-9A, Rev. 2).
The contact area (A) is the plate thickness (T) times the arc
length (L) of the rounded portion of the plate washer.
The arc length (L) is the length of the rounded edge, or one
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NRC Ouestions (9/14/79)
0.1/2 Page 2 of 2
fourth the circumference of a circle of that radius (R).
Plate Washer thickness (T) 2.375 in.=
Radius of rounded corner (R) = 1.5 in.
L = 2n R = 2n (1. 5 ) = 2.36 in4 4
5.6 in.2A = TL = (2.375)(2.36) =
D= 4A 4(5.6) = 2.67 in,
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The attached Fig. 2-1 shows the projected area used for compu-
ting the equivalent diameter of the plate washer impact.
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NRC Questions (9/14/79)
Q. 4 Page 1 of 4
For the cable trays ABA401, ABA010, and AEA380, which may
be exposed to a drop of a plate washer in excess of 3 feet,
you have stated that suitable guides or alterr; ate protection
will be provided. Describe the guides or alternate protec-
tion and show pictorially how the protection will work..
Answer:
This answer discusses Mie methods which Licennee will use to
assure that all cable trays in the Cable Spreading Room will
be procected against any drop of a plate washer. As indicated
in Licensee's respo:.se dated September 5, 1979 to NRC Systems
Branch Question No. 10(c), cable trays ABA401, TBA010, and
ABA380 may be exposed to a drop of a plate wasner in excess of
thr ee (3) feet. If the present bolt hole locations were to be
changed, cable trays ABA595, ABA285, or NPA206 penetrating the
R line wall might also be exposed to such a drop. The cable
trays located near the R line wall in the Cab;e Spreading Room
which might be exposed to a drop of a plate washer while the
washers are being installed on the R line wall are shown in
attached Figures 4-1 and 4-2.
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In order to provide protection to the cable trzyn passing
through or near the R line wall which could be exposed
to a drop of a plate washer, and to facilitate installa-
tion of the plate washers, Bechtel plans to erect
tubular scaffolding with nominal 2" thick timber planking
in the Cable Spreading Room. The scaf folding is E tandard
construction equipment, and will be bolted together
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NRC Questions (9/14/79)
Q. 4 Page 2 of 4
from 2-3 inch diameter steel pipes. It is light weight mate-
rial without sharp edges and does not present a risk of damage
to either cables or cable trays.
As shown in Figures 4-1 and 4-2, the timber planking will be
perpendicular to and flush against the wall directly beneath
each applicable plate washer location. It will be placed so
that the maximum height a washer can fall onto it is 3 feet.
An on-site test will be performed by dropping a steel washer
from 3 feet onto the planking. If the washer penetrates, or
significantly deforms, the planking, another layer will be
added.
The planking will be cut to the length required to protect the
cable trays below it. Though for the most part the length of
the planking will be seven feet, the maximum length in some
instances will be determined by the space available. In all
cases the length of the planking will be sufficient to prevent
a plate washer from falling more than 3 feet onto a cable tray.
The washers will be pulled across the floor of the Cable Spread-
ing Room, and lifted onto the scaffolding. The washers will
not be lifted over cable trays unless the planking is in place
and secured to protect the cable tray. Any cable tray which'
could conceivably be struck by a washer dropped while it is
being lifted to the scaffolding will be protected by the steel
cable tray covers described in Licensee's response, dated
Septemoer 5, 1979, to NRC Staff System Branch Question No. 11.
As discussed in that previous response, cable tray covers will
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NRC Questions (9/14/79)
Q. 4 Page 3 of 4
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protect the cables from a plate washer drop of less than three'
feet. No plate washer will a s lif ted to the scaf folding in s
an area in which it is possible for it to fall more than
three feet onto an adjacent cable tray. After the plate
washer is lif ted onto the planking, it will be pulled across,
the planking to the R line wall where it will be lif ted
into position. The protection provided by the scaffolding andplanking, together with the cabic tray covers, assures that nounprotected cable tray will be exposEJ to the drop of a platewasher and that any such drop will be limited to 3 feet.
The scaf folding planks will be treated with the "Plamort-WC"fire retardant, as will be discussed in Licensee's response
to NRC Staff Question No. 3, dated September 14, 1979. The
amount of planking in the Cable Spreading Room at any onetime during the modification work will be limited so that
the resulting combustion loading in the room due to the plank-2
ing will be less than 1.0 lbs/f t compared with an existing2loading of 15.8 lbs/f t , (PGE-1012 Table 3-1). At all
times when the planking is in the cable Spreading Room, a
fire watch will inspect the area on an hourly basis.-
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Protection will also be provided to the cable trays on the
vest side of the R-line wall during the modification program.
Potential hazards to those cable trays includo dropped hand
tools, bolts or nuts, and lumber cribbing for Plate 8 instal-
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NRC Questions (9/14/79)
Q. 4 Page 4 of 4
I
lation*. Field inspection has established that the maximum
drop height for any of these items onto these cable trayt willnot exceed 3 feet. As explained in Licensee's redponse dated
August 13, 1979 to NRC Staff Structural Branch Question No. 11dated July 20, 1979, , cable tray covers will be used to protect
the cable trays on the west side of the R line wall from tools
and paterials to be used in that area.
* Protection of the cable trays from fire hazards of cutting
and welding is discussed in paragraph 6 of Affidavit of
E. W. Edwards, dated August 27, 1979, on Consolidated Inter-
venors' Contentions Nos. 2A and C.
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NRC Questions (9/28/79)
Q. 1
Verify that the installed Hexcel energy absorbing material
will be
(a) " stabilized" in order to ensure the edge material is
stabilized and therefore will absorb the anticipated
amount of energy should it be crushed by a falling
plate.
(b) "precrushed" in order to eliminate the peak load shown
in Figure V-2 of Hexcel catalog #TSB-120.
Answer:
(a) The Hexcel energy absorbing material will be " stabilized"
by bonding a plate on the top and bottom of the material.
(b) The Hexcel energy absorbing material will be "precrushed"
in order to eliminate the peak load shown in Figure V-2
of Hexcel catalog #TSB-120.
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NRC Questions (9/28/79)
Q. 2
Previous responses have indicated, in response to the control
of dust, grit and debris, that the work area may be isolated.
In this regard, the staff believes a small portable enclosure
should be employed on the east and west inside walls of the
Control Room and the electrical auxiliaries room when drilling
holes in the walls. This box shall be capable of containing
and collecting any dust, dirt, debris and water that may enter
the room as the drill penetrates the wall.
Verify that such a small enclosure and collection means will
be provided in order to preclude the release of this material
inside the rooms.
Answer:
A small enclosure will be used on the inside of the walls as
outlined in the above question. It will be constructed so
as to collect and contain any dust, dirt, debris and water
incidental to the drilling. It will also be constructed
such that a workman can hold the enclosure against the wall
with his hands, and at the same time be able to see the wall.
to determine when and where the drill bit is penetrating.-
The enclosure will have approximate dimensions of l' x l' x
3" and will weigh approximately five (5) pounds. Such an
enclosure will not pose a threat to electrical cables or
equipment in the event that the enclosure would be dropped.
Additional measures to control dust, grit and debris are
described in Licensee's response to Question No. 7 of this
set.
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NRC Questions (5,28/79)
Q. 4 Page 1 of 2
The Trojan response of September 5, 1979 to Systems Branch
question 10 is confusing in that it speaks of areas externalto Category 1 equipment. The staff believes that a fire
_watch patrol should be established to perform hourly inspec-
tions for areas where a fire could affect safety related
cables or equipment in which non-fire retardant wood will beused for concrete forms or other purpcses.
The person while assigned as a fire watch patrol should have
no other duties. This fire watch patrol should be instituted
when the non-fire retardant wood is taken into any of these
areas and continue until it is removed. The fire watch patrol
would not be necessary during the times when a continuous
fire watch has been established in an area for other reasons.
Identify each of the areas where such a fire watch patrol
would be necessary to monitor for fires in areas where a fire
could affect safety-related cables or equipment.
Answer:
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The intent of Licensee's response dated September 5, 1979, to
Systems Branch Question No. 1G(i) was to indicate that, duringthe modification program describ?d in PGE-1020, Licensee willestablish a fire watch patrol when wood, whether fire-retardant
or not, is utilized in areas where a fire could affect safety-
related cables or equipment. The fire watch patrol will per-
form hourly inspections from the time any wood is brought intoany such area until it is removed, and will not be assignedother duties. The areas where such a fire watch patrol might
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NRC Questions (9/28/79)
Q. 4 Page 2 of 2
be necessary will be identified in Licensee's response to
NRC Question 3 dated September 14, 1979.
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NRC Ouestions (9/28/79)
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Q. 5
In reference to the construction noise levels in the control
room, response 18 to the staff's July 20, 1979 questions, you
indicated that "Should it be determined by the plant operator
in the Control Room that excssive noise is being c'reated,lighter weight tools or other means of concrete removal will
be employed". The staff believes it is essential that if
either the NRC IE resident inspector or the plant operator
should determine that excessive construction noise is being
created, lighter weight tools or other means of concrete re-
moval will be employed.
Verify that the abov' "iditional control on control room noise
is acceptable and will be complied with.
Answer:
In the event that either the NRC IE Resident Inspector or the
Plant operator determines that excessive construction noise is
being created, lighter weight tools or other means of concrete
removal will be employed.
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NRC Questions (9/28/79)
Q. 6
Presently it is proposed to utilize a positive feed control
drill on the east and west control building outer walls. Fur-
ther a person will be stationed on the inside for the purpose
of detecting when the wall has been penetrated and notifying
the driller via radio communications or by sound or battery
powered telephones. Describe and discuss any other additional
measures that can and will be implemented to further provide
assurance the drill will not be allowed to penetrate to such
an extent as to damage equipment within, e.g., positive stops
or a paint strip on the core drill to alert the driller that
wall penetration is imminent.
Answer:
Conventional practice for such drilling operations includes
the use of marking on the core drill so that the drill operator
knows where his drill bit is located in relation to his planned,
penetration depth. Such a marking procedure will be used for
all concrete or masonry core drilling required for the modifi-
cation work. The type of marking used will be one that the
drill operator can easily see while operating the drill.-
Either a tape or painted stripe is the method which we would
plan to use.
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NRC Questions (10/2/79)
Q. 9
Your June 29 response to question 3 and PGE-1020, Revision 2
indicates that the appropriate factor of safety for the Nel-
son studs is 2. Your June 22 response to question 22 indi-
cates that a factor of 3 was used in the design of the studs
and, therefore, may be more appropriate. Clarify this apparent
inconsistency.
Answer:
In PGE-1020 Section 3.2.4.3 and in Licensee's response dated
June 29, 1979 to NRC Question No. 3, it is stated that the
allowable design values for Nelson studs are one-half of the
values given in Table 15 of the Nelson Division of TRW, Inc.
publication, " Design Data 10 - Embedment Properties of Headed
Studs". A justification for the allowable design values is
presented in Licensee's response dated June 22, 1979 to NRC
Question No. 7
Licensee's response dated June 22, 1979 to NRC Question No. 22
indicates that the maximum calculated forces on the studs are
one-third of the values given in Table 15 of " Design Data 10 -
Embedment Proper ties of Headed Studs'; . Since the calculated
forces are less than the allowables, the design of the studs
is adequate.
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NRC Questions (10/2/79)
Q. 16
Your July 10 response to question 13 indicates that the
maximum vertical amplification factor is 16 percent whileyour September 5 response to question 15 indicates that it is
13 percent. Therefore, provide the correct maximum vertical
amplification factor.
Answer:
Licensee's response dated July 10, 1979, to NRC Question No.13 stated that the maximum vertical amplification factor is
16 percent. Licensee's response dated September 5, 1979, to
NRC Question No. 15 states that "the dead load was reduced13% to account for vertical motion". Thus, the 13% is the
reduction in dead load, and is not a value for vertical
amplification.
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NRC Questions (10/2/79)
O. 18
In your September 5 responses to questions, the response toquestion 17 indicates that for the combination of dead, live
and SSE loadings, the maximum allowable stress in bending andtension is limited to 0.9 fy and the maximum allowable shear
stress is limited to 0.5 fy. Verify that this limitation was
imposed for the evaluations of steel elements discussed in the
responses to questions 18 and 25.
Answer:
In Licensee's responses dated September 5, 1979 to Structural
Branch Questions Nos. 18 and 25, the maximum allowable stress
in bending and tension of the steel elements was limited to
0.9 f and the maximum allowable shear stress was limitedyto 0.5 f for the load combinations referred to.y
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