Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
ACCESSION #: 9507170404
KEYSTONE
3950 Greenbriar, Stafford, Texas 77477 Anderson, Greenwood & Co.
July 14, 1995
VIA FAX TO NRC OPERATIONS CENTER (301) 816-5151
Document Control Desk
U.S. Nuclear Regulatory Commission
Washington, D.C. 20555
Ref: 10CFR21 - Reporting of Defects and Noncompliance
Gentlemen:
The purpose of this correspondence is to comply with 10CFR21, paragraph
21.21(c)(1). We have information reasonably indicating that Model 81P
relief valves manufactured by Anderson, Greenwood & Co.(AGCO) if adjusted
in the field using air as the test media, may not exhibit a set pressure
within the specification tolerance.
AGCO's Model 81P is a relief valve designed for liquid "thermal relief"
applications. These valves are factory set and sealed to the specified
set pressure using liquid (water) as the test media. The specified set
pressure tolerance is +/- 3%.
The maintenance instructions for the 81P include instructions for valve
set pressure adjustment (see paragraph 3.0 in attached document number
N05.9040.180). The recommended procedure is identical to the factory
procedure using liquid. However, a second method using air is provided
where set pressure is determined by adjusting the valve's first crack or
leak to 95% of nameplate set pressure.
In very limited tests performed on July 13, 1995, we discovered that
valves adjusted in the field to 100 psi set pressure using the air test
method may exhibit a set pressure deviation of up to + 40% when tested on
liquid to the factory procedures.
Our preliminary tests indicate the deviation will be largest for low set
pressures (100 psi). There may be little or no deviation at high set
pressures (2000 psi).
As of this writing, only a few valves have been tested. More extensive
testing needs to be performed in order to evaluate this potential
problem. However, Duke Power's Oconee Nuclear Power
P.O. Box 944, Stafford, Texas 77497-0944 Phone: (713) 274-4400,
Telex: 0775219,
Fax: (713) 240-1800
Document Control Desk
U.S. Nuclear Regulatory Commission
July 14, 1995
Page 2
Plant has advised us that some valves have been readjusted by them using
the air pressure method. There may be other plants that have utilized
this procedure.
This notice is only applicable to any 81P relief valve that has had its
set pressure adjusted after shipment using air as the test media and
first crack at 95% of set pressure as the criteria. Any valve that has
AGCO's factory lead seal unbroken is unaffected.
We have commenced a test program to document the correlation between the
two test methods. We expect to complete this in 2-3 weeks. Our
evaluation will be reported to the NCR.
A list of the quantity and location of 81P relief valves that have been
shipped by AGCO is attached. We are also in the process of identifying
all customers who have purchased this model from us so that, upon
completion of the evaluation, they may review and take appropriate
action.
Should you have any questions, please feel free to contact Alan West at
(713) 274-4550 or Doug Snyder, Director of Quality, at (713) 274-4668.
Very truly yours,
ANDERSON, GREENWOOD & CO.
J. Alan West, P.E.
Vice President, Engineering
Douglas P. Snyder
Director of Quality
JAW:mnp
Atta.
c: Mr. Greg Hyland
Mr. Ed Ross
Mr. Juan Gomez
Mr. Randy Shoff
MODE81P7.145
Attachment "A"
Nuclear 81P User List
COMPANY QUANTITY
Duke Power Company 123
Northeast Utilities 8
CFE (Ciudad Federal Electricidad) 5
Virginia Power 10
Pennsylvania Power & Light 27
Boston Edison 20
Centerior Service 13
Nebraska Public Power District 5
Vermont Yankee 2
Omaha Public Power District 9
GPU Nuclear Corporation 30
Georgia Power 4
KHIC (Korean Heavy Industries Corp.) 2
PSE & G (Public Service Electric & Gas) 3
Entergy 35
TOTAL... 302
KEYSTONE
Anderson, Greenwood & Co.
A Subsidiary of Keystone International, Inc.
******
* EX *
******
DWN S.WILLIS 7-21-88 MAINTENANCE INSTRUCTIONS FOR
CHK M.LEANOS 7-21-88 TYPE 81P (-4 & -8 ORIFICE)
APPR D.PAPA 7-24-88
APPR J.BACA 7-25-88 SIZE REV
APPR A N05.9040.180 F
APPR
PAGE 1 OF 8
FORM NO. 910 J 5/93
ANDERSON, GREENWOOD & CO. NUMBER
N05.9040.180 Page 2 Rev. F
REVISIONS
REV. DESCRIPTION APPROVALS/DATE
F ECR #95-166-02 S.WILLIS 6-19-95
FORM NO. 915C 1/92
ANDERSON, GREENWOOD & CO. REPORT NUMBER
N05-9040-180 Page 3 Rev.
MAINTENANCE
INSTRUCTIONS
SAFETY-RELIEF
VALVE
TYPE 81P -4 & -8 Orifice
ANDERSON, GREENWOOD & CO.
3950 GREENBRIAR STAFFORD, TX. 77477 P.O. BOX 944 STAFFORD, TX. 77497
713/274-4400 FAX: 713/240-1800 TELEX:0775219
N05-9040-180 REV. D
ANDERSON, GREENWOOD & CO. REPORT NUMBER
N05.9040.180 Page 4 Rev. F
1.0 GENERAL
The Anderson, Greenwood Type 81P is a direct acting, spring loaded
safety relief valve for liquid service. It uses a plastic seat and
O-ring seals and is available with or without a vented bonnet.
Valves with vented bonnets are balanced against the effects of back
pressure.
2.0 VALVE REPAIR (Refer to Figures 1 and 2)
2.1 Disassembly
Remove lift lever bushing/cam assembly (Figure 2), if so
equipped, and cap. Relieve spring tension by turning the
pressure adjusting screw counter-clockwise.
Remove inlet bushing, bushing seal and valve internals.
Separate nozzle from guide by tapping top of spindle on soft
surface. Hold spindle in soft jaw vise and remove seat.
2.2 Repair
Inspect metal parts for wear. Parts with excessive wear should
be replaced. Parts with minor nicks or scratches can be
polished and reused. Refer to Figures 1 and 2 for recommended
spare parts. The numbers for these or any part are listed on
the drawing bill of material supplied with the valve.
2.3 Assembly
Assemble in reverse order of disassembly. Make sure the nozzle
is evenly seated in the guide. Lubricate threads, tip of the
adjusting screw and spindle and all static seals with Never
Seez NG-165 or equivalent lubricant. Lubricate sliding seals
on spindle with Desco 600 for set pressures 1000 psig and above
and Dow Corning FS 3451 for set pressure below 1000 psig. Do
not lubricate seat.
If the valve was equipped with a lift lever, there will be two
1/4-28 nuts on the lift rod. If these nuts were removed during
disassembly they must be re-adjusted. To adjust, use the
following procedure: screw cap on valve and observe position of
the two nuts through the hole in the side of cap. The bottom
surface of the lower nut should be in the center of the hole.
When properly located, tighten the nuts. Remove the cap and
proceed with the set pressure adjustment. After the valve is
adjusted, install cap and lift lever bushing/cam assembly.
Lift handle must be in down direction, toward inlet.
ANDERSON, GREENWOOD & CO. REPORT NUMBER
N05.9040.180 Page 5 Rev. F
3.0 VALVE SET PRESSURE ADJUSTMENT
Where practical, Type 81P valves should be set using water and a 50
gallon pressure vessel.
Set pressure for a Type 81P is defined as 93% of that inlet pressure
where the valve "pops" or "gushes". When setting the valve using
water, use the following procedure:
(1) Increase the spring tension by turning the pressure adjusting
screw clockwise.
(2) Increase the inlet pressure to 107% +/- 2% of nameplate set
pressure.
(3) Reduce the spring tension until valve "pops" or "gushes" by
slowly turning pressure adjusting screw counter-clockwise. Set
pressure is 93% of this value.
Example: Nameplate Set = 75 psig
"Pop" or "Gush" = 107 +/- 2% (75) = 78.75 to 81.75 psig
Actual "Pop" = 80 psig
Actual Set = 80 (.93) = 74.4 psig
Reseat is not adjustable. It will occur at approximately 75% to 80%
of set. First measurable leak on increasing pressure should be a
minimum of 92 1/2% of set.
4.0 ADJUSTABLE TOLERANCES
SET PRESSURE VALVE OPERATING
RANGE CHARACTERISTIC TOLERANCE
ABOVE 70 PSIG +/- 3%
SET PRESSURE
70 PSIG & BELOW +/- 2 PSIG
100 PSIG & ABOVE CRACKING 92 1/2% ---
PRESSURE
50 PSIG TO 99 PSIG 80% ---
ANDERSON, GREENWOOD & CO. REPORT NUMBER
N05.9040.180 Page 6 Rev. F
5.0 SEAT LEAKAGE
5.1 General
If the valve leaks after repair, check for the following:
1. Full and even seating of nozzle and guide.
2. Foreign particles trapped between the seat and nozzle, if
any are found seat damage may have occurred and
replacement may be necessary.
If 1 and 2 reveal no evident seat leakage source, the
procedures described in section 5.2 may be used to eliminate
seat leakage.
5.2 Seat Sealing Procedures
Heat the valve for 15 to 30 minutes in an oven preheated to
250-300 degrees F. A concentrated heat source such as a heat
gun or open flame must not be used.
After the valve has air cooled to room temperature, retest per
Section 3.0 to insure seat tightness. If results have not
improved, the valve should be disassembled and the seat
replaced.
Page 7 Rev.
FIGURE 1 "TYPE 81P WITHOUT LIFT LEVER OR GAG" OMITTED.
Page 8 Rev.
FIGURE 2 "TYPE 81P LIFT LEVER OR GAG" OMITTED.
*** END OF DOCUMENT ***
