ML20235V411
| ML20235V411 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/24/1989 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| C311-89-2016, GL-88-14, NUDOCS 8903100170 | |
| Download: ML20235V411 (4) | |
Text
. _ _ _ - _ _ _
~
GPU Nuclear Corporatloa
. Nuclear
- e = g 48o o
Middletown, Pennsylvania 17057-0191 717 944 7621 TELEX 84 2386 Writer's Direct Dial Number:
February 24, 1989 C311-89-2016 US Nuclear Regulatory Commission Attn:
Document Control Desk Washington, DC 20555
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 GL 88-14 Response NRC GL 88-14 " Instrument Air Supply System Problems Affecting Safety-Related Equipment" requested each licensee to review NUREG-1275, Volume 2 and perform a design and operations verification on the instrument air system. The request included verification for three identified items and a discussion of the program for maintaining proper instrument air quality.
The GPUN response for TMI-1 is included in Attachment 1 to this letter.
Sincerely,
..D.
kill Vice President & Director, TMI-1 HDH/DVH/spb:2016 Attachment Sworn and subscribed to before me this J g h day of February, 1989.
cc:
W. Russell R. Hernan Resident Inspector
&LUV f buu W
/
Notary Public 8903100170 8902247' NOTARIAL SEAL PDR ADDCK 05000289 SHARON P. BROWN, NOTARY PUBUC P
PNVs M:00LETOWN BORO, DAUPHIN COUN7Y g
MYcCMM:SSION EXPIRES JUNE 1_2,1939 f.vy. 7c=eAshia Assecaton of Notaries GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation I t
GL 88-14 ATTACHMENT 1 GL 88-14 requested each licensee / applicant to review NUREG-1275, Volume 2, and perform a design and operations verification of the instrument air system.
Item _1 Verification by test that actual instrument air quality is consistent with the manufacturer's recommendations for individual components served.
i GPUN Response GPUN has reviewed the TMI-1 Instrument Air System (IAS) design in conjunction with the B&W Owner's Group Safety and Performance Improvement Program (SPIP).
As a result we believe the TMI-1 IAS supplies air of high quality. We also perform continuous dew point recording and monitoring of differential pressure across IAS pre and post filters.
In addition we perform a periodic IAS blowdown and monitor the pressure for critical components. GPUN has decided to provide additional assurance by a one time verification test that the air supply to instrument air components is of acceptable quality. This will be accomplished by selecting representative sample points at various locations in the system and confirming, via testing, that the air v:pply bring delivered to pneumatic components is acceptable. The sample point
- to be selected are distributed to canvas the air system in all major areas. The air quality limits established in ANSI /ISA-S7.3-1975 (1981) provided the guidelines for determining the acceptance limits for dew point, particle size and oil content. At this time we do not have the capability to do this testing in-house and as such are in the process of selecting a vendor to perform this service. The testing and analysis of the test results is expected to be completed by July 1, 1989.
Item 2 Verification that maintenance practices, emergency procedures, and training are adequate to ensure that safety-related equipment will function as intended on i
loss of instrument air.
l GPUN Response We have reviewed our maintenance procedures, emergency procedures and training i
on this subject. We have determined they are adequate to perform the intended functions.
In addition to the Inservice Testing (IST) Program for safety related valves, we have specific procedures for preventative maintenance on air compressors, back-up instrument air compressors, and air handling equipment, instrument air dryer inspection and desiccant change as well as general maintenance procedures that cover areas such as threaded fittings, compression fittings, valve l
repairs, cooler repairs, filter replacements, etc. The combination of these i
procedures provide an effective maintenance program.
In the emergency procedure area, we have a detailed Emergency Procedure 1202-36
" Loss of Instrument Air."
Loss of Instrument Air is an event oriented procedure and entered based on procedural symptoms. This procedure addresses in detail the required operator actions upon loss of instrument air. The procedure steps provide the immediate and followup actions. This includes the steps needed to remove decay heat from the Reactor Coolant System by natural or forced circulation cooling and restoring instrument air and its backup air system.
Training is conducted for operators and maintenance personnel. This training includes detailed instruction for each discipline.
For example, the operators are trained in the use of procedure 1202-36 and the overall importance of the instrument air system and the maintenance personnel are trained on the use of the maintenance procedures.
Item 3 Verification that the design of the entire instrument air system including air or other pneumatic accumulators is in accordance with its intended function, including verification by test that air-operated safety-related components will perform as expected in accordance with all design-basis events, including a loss of the normal instrument air system. This design verification should include an analysis of current air operated component failure positions to verify that they are correct for assuring required safety functions.
GPUN Response The design of the Instrument Air System has been reviewed to ensure that it is capable of performing its design functions. These functions include delivering air of suitable quality, ensuring that pneumatic valves will fail in a position that supports safe plant operation during all design basis events and, for valves that require air to move or maintain the safe position, that a sufficient quantity of air is available.
GPUN has reviewed the discussions and recommendations of NUREG 1275, Volume 2, as they apply to TMI-l's Instrument Air System.
In addition, a review, which utilized the recommendations of the B&W Owner's Group Safety and Performance Improvement Program for Instrument Air, placed the existing system design under additional scrutiny.
Except as indicated below, these reviews have been completed.
In some cases, actual testing of pneumatic components is ongoing or scheduled for future outages.
(Specific discussions on these items follow.) Pending completion of functional testing, the reviews have ascertained that the existing system design is capable of providing air of sufficient capacity, proper quality and in a method that minimizes the effect of system perturbations.
Several modifications are being planned to further improve system reliability.
l An engineering review has been performed for all safety related air operated I
components. This review documents the required fail safe position and associated justification for components required to support safe plant l
operation following design basis events.
This information will be used as the acceptance criteria for the functional tests discussed below.
1,
Eighty-six pneumatically operated safety related valves and dampers have been identified.
For those safety-related valves with spring return actuators, functional operability on loss of air can be simulated by repositioning the air supply solenoid valve and venting the air from the actuator. This simulated loss of air will result in the spring repositioning the valve.
We currently perform this test of these valves to the ASME Section XI Code, Article IWV-3415.
In addition as an added level of confidence, one time visual observations will be made of the valve movement to ensure correct positioning following air loss.
This one time testing is scheduled to be completed by the end of the 8R outage.
Six of the eighty-six safety-related valves have backup air accumulators to ensure operability on loss of air. To assure proper operation of valves with accumulators, the accumulators and asscciated piping / tubing and components will be tested to assure their integrity to maintain pressure to operate valves upon loss of normal instrument air. We have also confirmed that required accumulators and associated piping / tubing and components for safety related valves have been seismically designed.
Of those safety-related valves with accumulators, we have identified those to be tested (four) and provided justification for not leak testing the other two. Testing for accumulator air leakage will not be performed on these two valves since there are alternate means of performing the safety function. This testing will also include valve operation utilizing the accumulator volume.
This testing is scheduled for our BR outage.
Based upon our completed evaluations, and contingent upon successful completion of the functional testing discussed above, we have concluded the following.
The TMI-1 Instrument Air System design is in accordance with its intended function, and that air operated safety components will function as expected in accordance with all design basis events, including air loss. All air operated valve failure positions are correct for assuring the required safety functions.
1 1 l l