ML19220C138
| ML19220C138 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/21/1977 |
| From: | Ashe F Office of Nuclear Reactor Regulation |
| To: | Rosa F Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7904280286 | |
| Download: ML19220C138 (13) | |
Text
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DISTRIBUTION:
CTNTRAL FILE NRR READING PS READING erp 3 i1977
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PSB READING FASriE READING MEMORRIDUM FOR: Faust Rosa, Chief, Power Systems Brary:h, DSS FROM:
F. Ashe, Power Systems Branch, DSS THRU:
M. Srinivasan, Section Leader, Instrumentation and Control Systecs Branch, DSS
SUBJECT:
SITE VISIT REPORT FOR THREE HILE ISLAND UNIT NUMBER 2 On August 1-3, 1977, we met with repeesentatives of Metropolitan Edison Company, General Public Utilit.ies and Burns and Roe at the These Mile Island Unit Number 2 site located near Middletown, Pennsylvania. The purpose of the site visit was to supplement the review of the electrical design (based on the infonnation contained in the FSAR and the electrical schematics) with a view of the actual implementation of this design as installed ath the site. presents the specific items covered during this site visit.
Enclesure 2 contains a number of concerns which require further action by the applicant. By a copy of this trip report we request that Inspec-tion and Enforca:ent personnel at Region I offica follow up items 1, 2, 7, 9,10,aand also the applicable portions of itons 3 and 6 of, to a satisfactory resolution.- -
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WASHINGTON, D. C. 20555 Y%%f E q p q 1977 s f MEMORANDUM FOR:
Faust Rosa, Chief, Power Systems Branch, DSS F. Ashe, Power Systems Branch, DSS FROM:
M. Srinivasan, Section Leader, Instrumentation and bh' THRU:
Control Systems Branch, DSS SITE VISIT REPORT FOR THREE MILE ISLAND UNIT NUMBER 2
SUBJECT:
we met with representatives of Metropolitan Edison On August 1-3, 1977, Ccmpany, General Public Utilities and Burns and Roe at the Three Mile The Island Unit Numcer 2 site iocated necr Middletown, Pennsylvania.
purpose of the site visit wes to supplement the review o schematics) with a view of the actual implementation of this design as installed at the site. presents the specific items covered during this site visit.
Er. closure 2 contains a number of concerns which require further action By a copy of this trip report we request that Inspec-by the applicant.
tion and Enforcement personnel at Region I office follow up items 1, 2, 7, 9,10, and also the applicable portions of items 3 and 6 of, to a satisfactory resolution.
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Frank Ashe Power Systems Branch Division of Systems Safety cc:
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R. C. DeYoung D. Vassallo D. Skovholt R. Tedesco J. Glynn D. Ross I&E (3)
NRC PDR Local PDR M. Kennemuyi H. Silver M. Srinivasan F. Ashe L. Narrows 8 /
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EMCLOSURE 1 AGENDA AUGUST l-3, 1977 SITE VISIT THREE MILE ISLAND UNIT NUMSER 2 I.
Preliminary Discussion 1.
Plant layout for touring II. General Areas of Interest 1.
Control Rcom a.
General layout b.
Nuclear and reactor protection instrument arrange, layout, shielding, independence and identification.
c.
Rod position indication d.
Engineered safety feature sad reactor protection systems initiation and bypass switch arrangements.
e.
Diesel generacor control panels f.
Cabling in contrcl room (independence, separation, type, Icadin~f diid f_lre barrier provisions).
g.
Radiation monitcring panels.
2.
Cable Runs and Cable 3preading Area a.
General layout b.
Implementation of separation and independence criteria O/
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c.
. Penetrations and cable tercinatio.s d.
Underground cable installar:ans 3.
Switchgear Rocms a.
General arrangement b.
Physical and electrical independence of redundant electrical equipment c.
Potential for damage due to missiles, pipe whip, etc.
d.
Cable installation e.
Divisional identification 4.
Batte'y Installations a.
Eeneral arrangement b.
Physical and electrical independence between the two electrical divisions c.
Potential for damage from missiles, high energy line break, etc.
d.
Ventilation independence e.
Mcnitoring instrumentation 5.
Diesel Generator Installation a.
General arrangement of equipment b.
Physical and electrical independence of the t5o
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redundant units.
c.
Fuel supply system and its controls d.
Local controls and instrumentation panels a.
Auxiliary systems - starting air, ccmcustion air, ventilating air and cooling water systems 87
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- 6.
Instrument Piping Instaliation Physical independence and single failures a.
b.
Potential for damage frcm missiles, pipe whip, etc.
c.
Installed features for testing purpcses 7.
Offsite Incoming Power System (Switchjard and Transformersi Physical and electrical independence of equipment a.
b.
Switchyard break control system Potential for damage due to flooding, missiler, falling c.
structures, etc.
8.
Reactor, Auxiliary and Tur'.ine Buildings Protection system instrument arrangement and layout a.
b.
Potential for instrument damage due to missiles, pipe whip, etc.
. Separation and indepincence~ of piping and wiring to c.
redundant or diverse instruments d.
Provisions for testing the protection system instruments e.
Independence of the redundant electrical pcwer system equipment III.
Specific Areas of Interert 1.
Shutdown Panels (typical - Non-centrally located panels
'nroughout the piant) 2.
Manual Trip Sef tch (RPS): Manual Actuation Switch (ESFAS)
. 3.
Cable Spreading Area
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4 Diesel Generator Building
. breakers in this _ building and al'solthe _.
auxiliary building which isolate th siesel Generators frcm the 4.16Ky Engineered Safety Features buses 5.
Controls for the reactor protection system trip breaks (schematic diagrams and physical layout drawings) 6.
Primary system pressure tap connections (those which are associated with the reactor protection system) 7.
Switchgear in the auxiliary building 8.
t.evel sensors on the Scrated Water Storage Tank 9.
Identificatien of selected heat tracing that is powered from the safety buses (provisions which are included in the design to isolate these heating elements) 10.
Physical separation and independEiice of'redundafit trains 7ithin the main control recm consoles 11.
Electrical penetration - (both safety and non-safety) 12.
Main feedwater control, startup and bicck valves.
Physical location of these valves and their centrollers 13.
Differential pressure senscrs used for the reacter protection system power inbalance ficw ccmparator
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87 343
. 14.
Typical physical locations where redundant safety train electrical cables are not routed in accordance with Regulatory Guide 1.75 15.
Cabling fror.. the reactor protection system cutput to the main turbine stop valve controllers (tracing the as installed cable routings) 16.
Piping taps and flow measuring instrument to be used to assure long term baron mixing following a loss of coolant accident 17.
Tracing the physical routing of the hydrogen line associated with the makeup tank O/
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ENCLOSURE 2 ITEMS REOUIRING FURTHER 3.CTION
'4HICH RESULTED FRCM T M SITE '/ISIT ON AUCUST 1-3, 1977_
THREE MILE ISLAND UNIT NO. 2 1.
Control rocm canel number 3 It was ot 9rved that this Janel contained redundant cables associated with the containment pressure indicators which were not physically separated. The applicant agreed to provide physical separation for these cables and any other similar redundant cable arrangements within the main control room console panels.
The I&E will ensure that the above modifications are implemented satisfactorily.
2.
Bottom barriers and seals for redundant safety related cabinets Within the main control ream it was noted that there were no bottcm barriers and seals internally between_ redundant reactor protection system channel cabinets. This same concern was also noted for redundant diesel generator centrol cabinets.
In response to these concerns, the applicant stated that bottcm barriers and seals would be installed internally between these redundant safety system cabinets.
Tb: I&E personnel will assure that these barriers are installed adequately.
87 350 0
. 3.
Safety Features Actuation Cabinet Room Concern was expressed about a three phase 4.16 Ky bus duct passing through a portion of the cia'e spreading room.
While it was nc;er, that this bus duct is ccmpletely enclosed, additional supporting information is needed to substantiate the conclusion that a fault asscciated with this 4.16 Ky high energy circuit will not result in a challenge to any of the safety features actuation equipment and circuits located in the cable spreading rocm.
The applicant agreed to provide this information.
It was also observed in this room (near the 4.16 KV bus duct locatien) that redundant cable trays number 3248 and 4228 cross each other horizontally with less than the minimum vertical physical separation For (3 ft.) between them an' that no barriers had been installed.
this concern the applicant provided the barrier criteria to be used in all cable tray crossings of this type and stated that b-
'ers would be installed for these trays (ncmcer 32a3 and 4228) i. acccrdance with this criteria.
The I&E personnel will verify that the ibove mcdificaticn are imple-mented acc:rding to the separation critet ia.
4 Switchyard ins _tallation It was obser'ad that the two transmission towers which support the two incoming power supply circuits for the safety buses were physically
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khh located in close proximity to each other.
Due to the close proximity of these towers concern was expressed aboct how this aspect of tre design conformed to the requirement contained in General Design Criteria 17 which states, " electric pcwer from the transmission network to the onsite electric distribution system shall be supplied two physically independent circuits (not necessarily on by separate rights of way) designed and lccated so as to minimize to the extent practical the likelihood of their simultaneous failure under operating and postulated accident and environmental conditions."
The applicant agreed to provide the results of an analysis to assure that failare of one of these towers due to any postulated environ-mental conditions would not result in the degradation of the other tower.
5.
Arliliary Buildina It was noted that the shell side piping for the nuclear services closed cooling water system is physically iccated adjacent to safety Concern was expressed about a related electrical substation rooms.
break in this piping resulting in the partial flooding of these The applicant provided the design rating of this substation rocms.
piping and noted this matter wculd be checked further and the results provided accordingly.
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Electrical Penetrations For electrical penetration number 534 it was observed that cables which leave cable tray number 3105 ana enter the bottcm of this penetration were not suppcrted and otherwise did not make a good transition from the caole tray to the penetration.
7or this con-cern, the applicant stated that these cables would be properly supported and that the transition installation would be imoroved.
The I&E will verify that the above transition installation is aug-mented satisfactorily.
It was also noted that the safety penetrations were equipced with box enclosures. The applicant was not certain if these penetrations had been qualified with these enclosures and stated that this matter would be checked and the results provided.
7.
Instrumentation Racks For instrument racks 455, 467 and 472 (these racks contain trans-ducers which are associated with the reactor building pressure parameter and provide electrical connections to the reactor protec-tion and safety features actuation systems) it was observed that internal to these racks the corresponding RPS and SFAS channel wiring was not physically separated.
The applicant stated that a work order had been issued to change this wiring arrangement and that this internal channel wiring would be physically separated.
The I&E personnel will assure that this T.cdification is implemented satisfactorily.
8.
Undercround cable installation separation of The applicant was not certain about the physical redundant control and pcwer circuits associated with the switchyard It was breakers installed in steel enclosed concrete duct banks.
agreed that the layout drawings for these circuits would be reviewed their physical separation would and that this infomation concern be provided.
lanc term boron mixino followina a LOCA 9.
Flow sensors used to assure valve and flew sensors probe It was observed that the tap, root assembly (which is to be used to assure long term boron mixing folicwing a LOCA and is inserted in the piping run frem the reactor vessel hot leg to the suction side of the decay heat removal In pumps) is r.ot physically located in an easily accessible area.
response to this concern, the applicant indicated that permanent location of _this _ assembly.
scaffolding would be installed at the The I3E will verify that the above permanent scaffolding is installed.
Fire stoos and seals for walls and ficors 10.
_For many of the safety-related ccmpartment areas which contained wall and/or floor openings for cables and/or conduit it was noted These. areas that no fire stops and seals had been installed.
included the diesel generator recms, diesel generator fuel oil storage tank area, beneath censoles and panels within the main control room, battery rooms, ccmpartments for the batter:L cnar<;er.s and 7: ?.
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static inverters.
The applicant stated that fire stops and seals would be installed in all openings in fire walls, floors and barriers as identified in the Fire Hazard Analysis for Three Mile Island Unit Number 2.
The staff is in the process of evaluating the Fire Hazard Analysis for this station and on completion of this evaluation the I&E should assure that the abcVe stated fire stops and seals are installed in accordance with the acceptance criteria.
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