IR 05000275/1992006

Insp Repts 50-275/92-06 & 50-323/92-06 on 920225-0302.No Violations Noted.Major Areas Inspected:Installation of New Emergency Diesel Generator & Followup of Previously Identified Items

ML16341G511
Person / Time
Site:	Diablo Canyon
Issue date:	03/30/1992
From:	Narbut P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
Shared Package
ML16341G510	List: IR 05000275/1992006 ML16341G509
References
50-275-92-06, 50-275-92-6, 50-323-92-06, 50-323-92-6, NUDOCS 9204140071
Download: ML16341G511 (18)

Text

U. S.

AR R

G AT RY g~iN V SS 0 Report Numbers:

50-275/92-06 and 50-323/92-06 Docket Numbers:

50-275 and 50-323 License Numbers:

DPR-80 and DPR-82 Licensee:

Pacific Gas and Electric Company 77 Beale Street, Room 1451 San Francisco, California 94106 Facility Name: Diablo Canyon Units 1 and

Inspection at: Diablo Canyon Site, San Luis Obispo County, California Inspection Conducted:

Febr uary 25, 1992 through Harch 2, 1992 Inspectors:

F.

Gee, Reactor Inspector D. Acker, Reactor Inspector H. Freeman, Reactor Inspector K

Approved By:

ar ut, ct~ng ie Engineering Section a

e sgne

$ymm~ar:

n ec ion on Februar

99 thro h March 992 Re ort Nos.

50-275 92-06 and 50-323 92-06

<<d:

The areas inspected in this routine engineering inspection included the installation of the new emergency diesel generator in Unit 2 and follow-up of previously identified items.

Construction Nodules 51051, 51053 and 51063 and Inspection Procedures 37700 and 92701 were used as guidance for this inspection.

Jesuits:

General Conclusions and S ecific Findin s:

In general, the inspectors concluded that the new emergency diesel generator electrical systems were being installed in accordance with engineering requirements, craft personnel had adequate knowledge concerning electrical installation criteria, and there was adequate quality assurance overview of this project in the areas examined.

'9204140071 920330 PDR ADDCK 05000275 G,

PDR

'

The inspectors-found one example where the design change requirements for conduit support'spacing did not agree with FSAR commi.tments.

This matter is unresolved pending an evaluation of its significance.

The inspectors also noted many minor problems such as housekeeping (a large drill stored in an electrical, cabinet)

and examples -of uncovered openings to lube oil and air systems that should have been identified and corrected by licensee craft and inspection personnel.

Personnel appeared to be knowledgeable of requirements, but implementation and oversight could be improved.

i ni cant Saf t r

None Summ r of Vi at'ons None

~0>>

!Th hp t

t d

1 dit, d

p d

unresolved item and one follow-up ite i 1.

Persons Contacted DETAILS acific Gas -and Electric Com an

• M.

• H.

• H.

B.

• J

'R.

• T.

• D

• H.

B.

Angus, Manager, Technical Services Burgess, Director, System Engineering DeMitt, guality Assurance Engineer Goelzer, System Engineer-Griffin, Senior Compliance Engineer Hess, Assistant Onsite Project Engineer, NECS Moulia, Technical Assistant to Plant Hanager Hiklush, Acting Plant Manager Phillips, Director, Electrical Haintenance Savard, Special Project Coordinator, NECS

• Denotes those attending the exit meeting on March 2, 1992 The inspectors also held discussions with other licensee personnel during the course of the inspection.

k 2.

Previousl Identified Items 92701 i

a ~

Closed Unresolved Item 50-275 50-323 91-07-04:

Volta e to 125 Volt Direct Current Motor 0 crated Valves During the Electrical Distribution System Functional Inspection in June 1991, the. team identified a number of non-conservative conditions and assumptions in the direct current (dc) degraded voltage calculation for Auxiliary Feedwater Turbine Inlet Motor Operated Valve in Unit 1, FCV-95.

Subsequently in October '1991, the Motor Operated Valve Inspection (Report No. 50-275, 50-323/91-39) identified additional problems with the degraded voltage calculation for Unit 1 FCV-95.

This inspection also noted that test data for Unit 1 FCV-95 showed higher unseating current for this valve than the worst case conditions assumed for the degraded voltage calculation.

The inspectors observed that this high test current might indicate a potential problem with degraded voltage operability; however, the licensee concluded that the high unseating current was due to conditions of the test and would not occur during accident conditions.

The licensee also noted that the valve was required to operate early in'ccident sequences and would be unlikely to be required to operate under deg'raded battery conditions.

The inspectors considered this'

evaluation adequate.

The licensee was performing weekly testing of.

FCV-95 to confirm that their operability determination was correct.

During testing subsequent to the HOV inspection in December 1991, Unit 1 FCV-95 failed to operate under conditions which would be encountered during accident conditions.

The licensee concluded that a hardware change was necessary to ensure opening of Unit

FCV-95 under design bases conditions.

The licensee changed the operator

for FCV-95.

This operator change provided a higher mechanical advantage and increased valve opening time.

The licensee compared the new FCV-95 opening time to design basis accident criteria and concluded that the opening time was satisfactory.

In addition, the licensee's thrust calculation showed that the new operator provided sufficient mechanical gain to operate the valve at worst case voltage conditions.

With the new operator,

.

the degraded voltage calculation indicated satisfactory motor performance, even with the most conservative values and assumptions.

The inspectors reviewed the licensee's actions and conclusions and concluded that the calculations for the new operator had sufficient margin to demonstrate degraded voltage operability.

Due to the fact that FCV-95 was required to operate early in accidents the inspectors concluded that the errors in the original calculation wer'e of low safety significance.

This unresolved item concerning degraded voltage calculation is closed.

0 en Follow-u Item 50-275 50-323 91-25-01:

Cracked Pressure locks Insulators in ASL Transformers Diablo Canyon Power Plant (DCPP)

was notified of a potential

CFR 50.55(e) deficiency concerning cracked insulators (pressure blocks)

in Westinghouse ASL dry type transformers.

DCPP had purchased two ASL 1000 KVA transformers from Washington Public Power Supply System (WPPSS),

under purchase order 728800, as spare transformers for Units 1 and 2.

Six ASL type transformers were originally purchased from Westinghouse and installed in Units 1 and 2;.each unit has three transformers.

The transformers are used in the 4KV/480V vital busses F,

G, and H in the respective units.

The pressure blocks are located at the top and bottom of each primary coil.

They are situated between the pressure plate and the primary coil.

There are six pressure blocks at the top and six pressure blocks at the bottom of each of the three primary'oils.

Each transformer has a total of thirty-six pressure blocks.

The transformer coil is approximately four feet in length.

The compressive forces that hold the transformer coils in position act through the pressure blocks.

Each pressure block is made of solid porcelain material and has a varnish coating on the surface.

Cracks on the pressure blocks are identified by visual inspection.

In an inspection of the Unit 2 F, G,

and H 4KV/480V transformers during outage 2R4 (from August 31 to October 26, 1991), the licensee, identified one 3/4 inch hairline circumferentially oriented crack in one pressure block in the F transformer. 's previously described in Inspection Report 91-25, the licensee issued Operability Evaluation 91-05RO.

The operability evaluation concluded that'he presence of the hairline crack had an insignificant effect on the seismic qualification of the. transformer assembly and did not compromise the

ability of the transformers to perform their safety-related functions.

Based on the conclusion of the operability evaluation, the licensee did not plan to replace the one known cracked pressure block in the Unit 2 F transformer.

The licensee has established a-temporary procedure, TP TD-9107,

"Replacement of Pressure Blocks for Dry Type Load Center Transformer,"

Revision 2, dated December 26, 1991, to replace the cracked pressure blocks in the two spare transformers in the warehouse.

The licensee stated that the replacement would commence when the parts were available.

The corrective actions were tracked on Non-conformance Report DCO-91-EM-N063 and Action Request A0236940.

The inspector stated that the closure of this follow-up item (50-275, 50-323/91-25-01) will be determined by the following:

1)

The review of the results and the associated corrective actions of the licensee's planned inspection of the Unit

transformers during outage 1R5, which was scheduled for September 15, 1992.

2)

Further rpview of the acceptability of the cracked pressure block in the Unit 2 F transformer.

3)

The. completion of a revision of maintenance procedure E-52. 1, "Maintenance of Dry Type Load Center Transformer and 480 Volt Switchgear," to include inspection for pressure block cracking.

No violations or deviations were identified in the areas reviewed.

3.

Desi n Chan es New Emer enc Diesel Generator 37700 The inspectors reviewed the progress being made on the new (sixth)

emergency diesel generator (EDG).

The inspectors walked down the work areas with licensee personnel and independently witnessed work in progress.

The inspectors reviewed quality assurance and quality control involvement for this project.

a ~

Cable Racewa and Conduit Installation The licensee was installing and inspecting cables, raceways and conduit in accordance with Diablo Canyon Procedures (DCPs)

301, Revision 3, "Wire and Cable Installation,"

and 304, Revision 3,

"Installation of Electrical Raceway and Raceway Supports."

The inspectors walked down the cable runs between the cable spreading room and the new EDG room and compared these installations to the DCP requirements.

The inspectors also reviewed samples of engineering instructions for conduit installation and compared these instructions to the actual installation.

The inspectors:witnessed cable checks.

'The inspectors witnessed installation of conduit,

raceways and grounding wires in the new EDG room.

Criteria for cable, raceway and conduit installation was contained

'n the licensee',s Updated Safety Analysis Report (USAR), Sections 8.1.4.1 and 8.3.1.4, in DCP 301, and in DCP 304.

The =inspectors found the installation to be in accordance with the listed criteria except as discussed in the following paragraphs.

DCP 304, Paragraph 4. 1.8.4 required a minimum spacing of 1 inch between "...conduits that cross or run parallel..."

Examples of contact between new parallel EDG conduits were noted on the 140 foot level of the turbine building and in the new EDG room.

The licensee reviewed the basis for the 1 inch criteria and determined that separation was unnecessary for parallel conduit runs of the same train.

The-licensee committed to change DCP 304 to accurately reflect design requirements.

DCP 304, Paragraph 4.2.3 required that,

"No unsupported span (of conduit) shall exceed 8 feet 6 inches."

The inspectors noted new

'DG conduit in the turbine building which visually appeared to have support spacing which exceeded 8 feet 6 inches.

The licensee determined that the installation in question was installed in accordance with sheet 4 of Field Change E-15127',- Revision 0, dated March 6, 1991=.

This Field Change allowed a maximum distance between supports of 10 feet.

The inspectors noted that the con'duit span

.

criteria of 8 feet 6 inches was also the maximum value allowed by the USAR Paragraph 8.3. 1.4.7.

This item is unresolved pending licensee review of the adequacy of the existing supports, exact measurement of support distances and evaluation of the difference between the field change and the USAR (Unresolved Item 50-323/92-06-01).

Unresolved items are matters about which more information is required to ascertain whether they are acceptable items, violations',

or. deviations.

DCPs 301 and 304 contained criteria for quality control verification of completed cable, cable tray and conduit installations.

The inspectors noted that these procedures did not contain criteria for verification of cable tray and conduit fill.

A licensee representative stated that the fill criteria were -the responsibility of the design engineer and did not.require any field verification by craft or quality control personnel.

The licensee also'noted that a

walkdown by associated organizations of the proposed installation was required prior to starting the job.

The licensee considered that this walkdown adequately verified cable tray and conduit fill.

The inspectors stated that one purpose of a quality control program was to insure that the in-process and completed installation met selected design criteria.

The inspectors concluded that the addition of cable tray and conduit fill criteria in quality control procedures could have been an additional check which could enhance the chance of catching a design error.

However, the inspectors C

b.

checked the percent of fill in selected cable trays and conduits.

The installations met the licensee's criteria, as listed in the USAR.

The inspectors discussed cable, cable tray and conduit installations with craft, quality control and quality assurance personnel.

These personnel appeared knowledgeable in their areas of cognizance.

ew DG Room The inspectors monitored work taking place in the new EDG room.

The EDG had been leveled (preliminarily) and installed on its foundation.

C.

The licensee had just removed the protective covering from the new EDG skid.

The inspectors noted an uncovered opening to an air start solenoid valve and several uncovered openings to instrumentation for the lube oil system on the new EDG ski There appeared to be foreign material in an opening to a lube oil level switch.

The licensee covered the openings in question and indicated that the foreign material would be evaluated for removal.

The licensee determined that the uncovered openings were all for electrical connections and the openings did not penetrate into the internals of the new EDG.

The licensee also initiated a twice weekly walkdown of the skid area for cleanliness control and housekeeping.

The inspectors also noted that the end of the relief piping from the air start system pressure relief valves were uncovered.

The licensee covered these openings.

The inspectors found a large drill and its contro'I box inside the EDG exciter control panel.

The licensee removed this equipment.

The inspectors also inspected the internal wiring and connections in Diesel Generator -2-3 Control Panel GgD 23.

The inspectors found the wiring installation to be acceptable.

ualit Assurance Oversi ht of Work The inspectors reviewed the quarterly reports issued by the quality assurance organization specifically for the new EDG project.

The inspectors toured the construction areas with quality assurance personnel.

guality Assurance personnel had identified problems with the procurement specifications for the diesel silencer, problems with changes in the concrete used for safety walls, and problems with electrical separation.

Based on a review of the quarterly report and discussions with quality assurance personnel the inspectors concluded that the quality assurance organization was providing an effective review of ongoing and completed work for the new EDG.

No violations or deviations were noted in the areas inspecte Malkdown of Diesel E ui ment At A

t During the walkdown of the diesels and diesel support equipment, the inspector observed that there was no flame arrestor on any of the vent pipes coming from the diesel fuel oil storage and day tanks; The inspector asked the licensee for clarification on. the, requirements of the Diablo Canyon site.

The inspector observed that each vent pipe from the two diesel fuel oil

'storage tanks was located at 'ground elevation on the.west side of the turbine building.

The vent pipe was approximately five inches in diameter with the opening pointing downward.

A screen covered the opening.

The vent pipe was housed in a concrete enclosure.

The concrete enclosure had louvers on the sides to allow movement of air to the surrounding atmosphere.

The inspector also observed that each of the five day tank vents, an approximately one-foot-open-ended pipe, was extended straight outward from the west side of, the turbine building and next to the diesel crankcase exhaust.

The day tank vent pipe was approximately three inches in diameter at an elevation of approximately'.

thirty feet from the ground.

The Fire Harshall at Diablo Canyon indicated to the inspector that according to the Section 2-4.5. 1, Location and Arrangement of Vents for Class I Liquids, of the 1990 edition of National Fire Protection, Association (NEPA) 30, Flammable and Combustible Liquids Code, flame arrestors are only required for Class I liquids.

Diesel fuel oil has a

flash point 'above 120>F and is classified as a Class II liquid.

As such, flame arrestors are not required for these tanks.

According to Section 1-2 of the 1990 edition of NEPA 30, Class II combustible liquids are defined as those liquids having flash points at or above 1000F (37.80C)

and below 140oF (600C).

A flammable liquid is a

liquid having a flash point below 1000F (37.8<C)

and having a vapor pressure not exceeding 40 psia at 100>F.

Flash point is defined as the minimum temperature at which a liquid gives off vapor in sufficient concentration to form an ignitible mixture with air near the surface of the liquid within the vessel.

The inspe'ctor reviewed some randomly selected samples of the chemistry data on the diesel fuel oil and verified that the flash points of those samples were greater than 1250F, as the diesel fuel oil at Diablo Canyon is required by Technical Specifications Section 4.8.1. 1..3.c. l.c to have a

'flash point equal to or greater than 1250F,.

Based on the above review, the inspector concluded that the absence of flame arrestors on the diesel fuel oil tank vent pipes was acceptabl b.

Removal of the Hatch for Unit 1 Fuel Oil Transfer Pum Com artment During the walkdown of the diesel equipment, the inspector observed that

'

worker was lifting the hatch of the Unit 1 diesel fuel oil transfer pump compartment at the ground elevation in the turbine building.

At the time of the walkdown, the inspector did not observe any security personnel at the hatch; The label on the hatch to the transfer pump compartment stated:

"Zone 61, Diesel F.O.

PP-1. Security must be present-prior to hatch removal.

Ext 3330.

All personnel must be logged in 5 out."

-The hatch had a proximity switch that would alarm remotely in the security monitoring area if the hatch was open.

The licensee's plant security staff indicated to the inspector that there was a security guard in the vicinity of the hatch and furnished the name of the guard,to the inspector.

The licensee was also able to show the inspector the alarm entry on the alarm log for Zone 61 at the time in question, 12:36 pm on February 27, 1992.

The vital area entry log showed the badge number of the person entering the area and the date and time of the entry, but the name of the person entering the area and the exit date and time of the entry were not entered on the log.

These incomplete entries on the vital area entry log will be reviewed during the next security inspection at Diablo Canyon (Follow-up Item 50-275/92-06-02).

Exit Meetin The inspector conducted an exit meeting on March 2, 1992, with members of the licensee staff as indicated in Section 1.

During this meeting, the inspector summarized the scope of the inspection activities and reviewed the inspection findings as described in this report.

The licensee acknowledged the concerns identified in the report.

During this inspection, the licensee did not identify as proprietary any of the materials provided to or reviewed by the inspector r