ML20041E591

Annual Operating Rept 1981.

ML20041E591
Person / Time
Site:	Vermont Yankee
Issue date:	03/02/1982
From:	VERMONT YANKEE NUCLEAR POWER CORP.
To:
Shared Package
ML20041E589	List: ML20041E588 ML20041E591
References
NUDOCS 8203110122
Download: ML20041E591 (8)

Text

. .

I. OPERATIONS

SUMMARY

A. Changes in Facility Design

1. The following changes required authorization from the Commision:

a) EDCR 80-54, ECN 2, RCIC Break Detection Logic EDCR 80-54 was completed 11/27/81.

This EDCR replaced existing relays with time delay relays in the RCIC pipe break detection circuitry.

The result of this is that any transients in the system that last for less than the time delay will not actuate the isolation logic. Authorization for a technical specification revision related to this design change was received from the NRC on November 27, 1981.

2. The following changes did not require prior Commission approval but were reviewed by PORC. It was agreed that each did not involve any unreviewed safety questions as defined in 10 CFR 50.59(a)(2) based on the information presented.

a) EDCR 79-51, Post Accident Sampling System EDCR 79-51 was completed 12/31/81.

This EDCR provided the capability to sample reactor coolant during an accident condition such that the reactor building becomes inaccessible. This capability is required by NUREG-0737, Item II.B.3.

b) EDCR 80-43, CRD Hydraulic System Vents EDCR 80-43 was completed 1/12/81.

This change increased the reliability of the CRD hydraulic system vents by the following changes:

1) Reinstalled the discs in the vent line check valves. This prevents water from entering the HVAC ducts on scram reset and provides a backup primary coolant boundary should the associated vent valve fail to close.

i 8203110122 820302 PDR ADOCK 05000271 g PDR

2) Corrected the pitch of the installed vent piping so that it drains back to the SDV if water enters it. This helps ensure long term operability of the vent valves.

3) Cross connected the vent lines between the vent valves and the SDV's. This insures a vent path

.! for SDV draining should one vent path be j inoperable, due to a failed valve, or other reason.

c) EDCR 80-53 ECN-4, Pipe Supports for the CRD Insert / Withdrawal Lines EDCR 80-53, ECN-4 was completed 11/30/81.

The ECN increased the scope of the change to include pipe supports outside the drywell and

fixes for existing hangers.

d) EDCR 81-05 RWCU Check Valve Addition EDCR 81-05 was completed 11/14/81.

This design change installed an additional check i j valve on the return line for the RWCU System.

! The addition of this valve was undertaken to f prevent the introduction of a steam environment to i electrical equipment in the area in the event of j a high energy line break.

e) EDCR 81-22, RCIC Suetion ' Transfer f

EDCR 81-22 was completed 11/25/81.

This change automated the RCIC suction transfer from

the CST to the torus on a CST low water level signal.

l A new seismically qualified instrument rack with two level transmitters was installed at the CST, bistables and relays were installed in cabinet 25-5B, relays were installed in CRP 9-30, and cable was run between

}' these three points and CRP 9-4 to make the necessary circuitry modifications.

f) EDCR 81-23, ECN-2, Feedwater Check Valve Replacement EDCR 81-23, ECN-2 was completed 11/27/81.

This change provided for the replacement of two

. existing outboard feedwater check valves with Anchor l Darling 16", 900 lb, swing check valves.

g) EDCR 81-27. Feedwater Nozzle Leak Detection System PDCR 81-27 was completed 12/10/81.

i i

- . . - _ w. - __- - - ~-_.--.. _ . , _ - . - - - - - - - - . _ _ _ - e._ _a

This change provided a detection system for leakage past the feedwater sparger thermal sleeve into the annulus area between the thermal sleeve and the feedwater nozzle. The system consists of four thermocouples mounted on each feedwater nozzle.

One thermocouple will be mounted on top of the nozzle and the other three in the lower 180' of the nozzle.

A differential temperature between the top and bottom thermocouples would indicate leakage.

h) EDCR 81-42, Containment Air Monitoring System Sample ,

Line Modification

EDCR 81-42 was completed 12/1/81.

This change provided for the piping modifications to the Containment Sampling System that will allow the installation of a Class IE oxygen / hydrogen analyzer sys' tem at a later date.

1) PDCR 78-9. Supplement 1 Diesel Generator Rooms Sprinkler System Seismic Hangers PDCR 78-9, Supplement 1 was completed 1/30/81.

Rangers were installed to support the Diesel Generator Rooms A & B Manual Sprinkler System piping.

The original hangers were determined to be inadequate following a seismic analysis.

j) PDCR 80-18, Switchgear C0 System Modification PDCR 80-18 was completed 3/27/81.

This design change improved upon the previously installed switchgear CO2suppression system.

1 A time delay for the closure of the room's exhaust damper was installed and the nozzle orifices were a

replaced with ones of smaller size. It is evaluated that these changes will eliminate pressure spikes, increase CO 2 distribution, and reduce CO leakage.

2 k) PDCR 80-19, 4" CUW-3 Piping Modification I

PDCR 60-19 was completed 1/2/81.

This design change was written to document the addition of a sockolet fitting to the 4" CUW-3 line. The sockolet was added to accommodate purging

of the 4" CUW-3 line in order to make the necessary

} repairs required by MR-1471.

1) PDCR 81-01, Scram Pilot Air Hender Low Pressure Scram PDCR 81-01 was completed 5/12/81.

This design change provided a method of meeting an NRC order for modification dated January 9,1981 by providing a reactor trip on low air pressure in the scram pilot air header.

m) PDCR 81-02, Relocation of Fire Main PDCR 81-02 was completed 6/2/81.

This design change relocated a section of the plant's outside fire main which, if Icft in place, would be covered by the New Warehouse (PAR 80-28). In addition, the fire system water supply for the stockroom / boiler room / diesel generators were re-located and upgraded. The supply header was provided with two supplies and now contains additional isolation valves.

n) PDCR 81-03, HPCI Start Modification PDCR 81-03 was completed 10/14/81.

This design change modified the HPCI turbine governor control system so the valves were partially shut when steam is admitted. This provided for a more controlled opening of the turbine governar valves eliminating the large surge of steam on turbine start and the associated transient. The smoother start also served to minimize the possibility of a system isolation due to the steam leak detection differential pressure switches as discussed in NUREG 0737, Item II.K.3.15.

o) PDCR 81-04, Instrument Air check Valve Replacement PDCR 81-04 was completed 11/20/81.

This change provided for replacing the present hard seat lift type check valves V72-89B, V72-89C, V72-103A, l and V72-103B in the instrument air system, used for I

containment isolation, with soft seat type check valves.

l 103A and 103B are in parallel and combined into a l common line. 103A and 103B were replaced with a l single new check valve which was placed in the common line, eliminating one check valve and reducing the amount of repiping. These valves improve low pressure checking and leak test results.

l l

I

p) PDCR 81-05, PCLRT Modifications PDCR 81-05 was completed 11/10/81.

This design change installed test connection to facilitate Appendix J leak testing of specific Drywell Sump Valves, and PCAC Valves. In addition, a blocking valve was installed along with the test connections for the PCAC valves, q) PDCR 81-07, Jet Pump Beam Replacement PDCR 81-07 was completed 11/6/81.

This change replaced the nineteen BWR-3 and one BWR-4 jet pump beams with twenty BWR-4 beams that have undergone a special heat treatment process to increase their strength and resistance to cracking. Untreated beams have exhibited a tendency to crack and fail early in plant life.

r) PDCR 81-10, RWCU Heat Exchanger Vent & Drain Line Modification PDCR 81-10 was completed 17/7/81.

This design change modified the RWCU system as follows:

1) replaced the 1" x 3/4" reducing couplings in the heat exchanger vent and drain line, 2) replaced certain flanges on the pump suction lines with spool pieces,

3) replaced the 4" x 3" concentric reducers in the pump suction lines with 4" x 3" eccentric reducers,

4) replaced the 4" x 3" concentric reducer on the "B" pump discharge line with a 4" x 3" eccentric reducer and improve the pitch of the "A" discharge line, and

5) removed certain 1 1/2" couplings in the pump discharge lines.

s) PDCR 81-11, RWCU Temporary Piping

(

l PDCR 81-11 was completed 12/2/81.

This change installed spool pieces upstream and downstream of the clean-up demineralizers in lines 4"-CUW-4A and l SB respectively, that allowed the clean-up demineralizer to be used during the outage when normal flow paths were unavailable. In particular, piping around the regenerative heat exchanger was replaced preventing the reactor cavity and vessel normal clean-up flow path from being useC During this time, water was directed from a temporary connection in the RRR system head spray line, 4"-RHR-34A, to the clean-up demineralizer with return from the demineralizers to the RHR pump suction via a connection to 8"-RHR-39. The components that remained as permanent parts of the systems

after removal of the temporary piping were flanges and spool pieces in the 4" clean-up lines and a weldolet isolation valve and pipe cap in the 8" -

RHR-39 line. The connection from the head spray line was made by removing a check valve bonnet which was replaced after removal of temporary piping.

t) PDCR 81-22, Removal of the Reactor Vessel Head Spray Line -

PDCR 81-12 was completed 12/2/81.'

This change removed a section of the RHR 19 line that supplies the reactor head spray. This line had been demonstrated to be susceptible to IGSCC.

u) PAR 79-20. Control Room Humidifie_r PAR 79-20 was completed 1/7/81.

This alteration installed a humidifier and associated controls and alarms for the Control Room.

v) PAR 79-24. Service Water to the RBCCW Heat Exchanger Cross-Connect PAR 79-24 was completed 1/12/81.

This alteration installed 4" bypass valves around V70-92 A & B.

! w) PAR 80-32, Containment Inerting Instrumentation and Makeup Feedline PAR 80-32 was completed 5/1/81.

This PAR addressed piping modifications which are l required for supplying N t containment services, 2

makeup 2N f r drywell/ torus AP and TIP for short term i and transition to long term inerting.

j x) PAR 81-07, Chlorine Monitor-at the Spray Pond PAR 81-07 was completed 9/10/81.

I l

l

An Orion Model 1770 Chlorine Monitor was placed at the spray pond drain for detecting residual chlorine in the blowdown. The monitor provides input to a recorder and meter at the hypochlorite panel in the turbine building. This will allow more accurate control of chlorination without exceeding our discharge limits.

y) PAR 81-21, Union Carbide Sandjet Process PAR 81-21 was completed 9/25/81.

This PAR addressed the piping changes and necessary preparations required to test the Union Carbide Sandjet Cleaning / Coating process. The "Sandjet" process was designed to, a) remove existing S.W.

corrosion in 3 to 12 inch lines, and b) prevent future corrosion buildup. This change was part of the overall program t:. eliminate service water corrosion. This process sandblasted the inside of the line so that a epoxy polyamide coating could be applied for corrosion protection.

The Sandjet process was tested on the 4" service water feed to the makeup water system (4" SW-27). Three i spool pieces were added to 4" SW-27. Two of these pieces were used to connect the required Union Carbide Sandjet equipment while the other spool piece was used primarily to inspect the quality of the sandjet cleaning and coating process.

z) PAR 81-29, Oxygen Injection Probe PAR 81-20 was completed 11/22/81.

This alteration installed an oxygen injection probe into the condensate pump discharge header. This task is part of EPRI Project' RP 1934-1.

B. Tests or Experiments

1. The following tests or experiments required authorization from the Commission:

. . ._ .. . . .. - . .-. . - . -- -~ --- - - = . - . . .

l

' ' ~

a) STP 81-01, Stability and Recirculation Pump Trip Testing STP 81-01 was completed 3/19/81.

The stability test provided data to support plant i i performance and qualification of stability models.

The recirculation pump trip test provided data for i qualification of the plant transient model'. Authoriza-I tion for a technical specification revision related to this test was received on March 11, 1981.

I

2. The following tests or experiments did not require prior Commission approval but were reviewed by PORC. It was agreed that each did not involve any unreviewed safety questions as defined in 10 CFR 50.59(a)(b) based on the

information presented.  !

a) STP 81-02, Safety / Relief Valve Discharge Testing STP 81-02 was completed 3/11/81.

This test involved manually initiating safety / relief valve actuation and collecting data to determine the response of the torus and its supports to the valve actuation under both cold and hot pipe conditions.

C. Safety and Relief Valve Failures anu Challenges j During 1981 there were no challenges to or failure of the

) safety and relief valves.

4 j

i i

4 l

l l

..