ML20059M693
| ML20059M693 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/17/1993 |
| From: | AFFILIATION NOT ASSIGNED |
| To: | |
| References | |
| OLA-2-I-MFP-010, OLA-2-I-MFP-10, NUDOCS 9311190248 | |
| Download: ML20059M693 (12) | |
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NCR DCO-91-TN-N048
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MANAGEMENT
SUMMARY
On 5/24/91, during a review of STP V-18 it was discovered that valves SI-8900A through D,
SI-8905A through D and SI-8819A through D were not individually measured for full flow, contrary to the recommendations of GL 89-04.
However, through the performance of STP V-15/V-4A the subject j
valves were verified to stroke open to pass the post-accident flow
- rates, and therefore the Inservice Testing (IST) requirements were met and this event was not reportable.
The root cause has been determined to be personnel error i
because the responsible personnel did not recognize the need to measure the flow through the subject valves individually in j
accordance with Position 1 of GL 89-04.
I A contributory cause has been determined to be lack of l
understanding of GL 89-04 requirements and confusion of corrective actions from previous NCRs.
The following items are part of'the' corrective'?.ctione:
1.
Further train all applicable engineers on GL 89-04, the IST Plan and perform a review of their systems.
l 2.
System engineering will provide additional training regarding the requirements of the IST program and the specific requirements contained in GL 89-04.
3.
Procedures will be revised to measure the individual l
loop flow.
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91NCRWP\\91TNN048.PGD Page 1 of 12 l
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i NCR DCO-91-TN-N048 February 7, 1992 NCR DCO-91-TN-N048 IST Generic Letter 89-04 Requirements I.
Plant Condition:
Units 1 and 2 operated in various modes at various power levels while this condition existed.
II.
Description of Problem:
A.
Problem NRC Generic Letter 89-04,
" Guidance on Developing Acceptable In Service Testing Program," dated April 3,
1989 was issued to provido notification of potential problems identified during NRC inspections of In Service Testing (IE') programs.
Generic Letter 89-04 Position 1 discusses full flow testing of check valves to verify that they stroke open sufficiently to pass the flow required to respond to an accident or plant transient.
Position 1 also states that " Knowledge of only the total flow through multiple parallel lines does not provide verification of flow rates through the individual valves and is not a valid full stroke exercise."
DCPP was identified as a Table 2 plant with an approved IST program plan and an SER issued on the IST plan.
Therefore PG&E was not required to respond formally to Generic Letter 09-04.
The Generic Letter. stated that "The technical positions round in Attachment 1 of this generic letter were used by the staff-in reviews of IST programs."
The NRC - SER (dated 12/22/.90) identified valves SI-8818A through O as valves that ' tere not^ tested individually by the full flow test..
Disassembly and inspection of SI-8818A through D was added to STP.V-18 revision 3, dated June 15, 1989.
On 5/24/91, during a review of STP V-18 it.was discovered that valves SI-8900A through D, SI-8905A through D, and SI-8819A through D were not individually tested for full flow, contrary to the requirements of GL 89-04.
The IST Program Plan specifies STP V-4A as a full stroke open test for these check valves.
STP V-4A utilizes the header flow for indication of full stroking open of the subject valves.
B.
Inoperable structures, components, or systems that 91NCRWP\\91TNN048.PGD Page 2 of 12 C
).
-i NCR DCO-91-TN-N048 i
November /, 1991 l
i l
contributed to the problem:
None.
C.
Dates and approximate times for major occurrences.
l 1.
November 20, 1988:
STP V-15 performed during 2R2 l
verifies individually full flow l
through SI-2-8819A through D,
i SI-2-8905A through D.
2.
December 22, 1988:
NRC issues SER for DCPP IST program.
l 3.
April 3, 1989:
NRC Issues Generic Letter 89-04 l
which requires Table i plants perform a
review and take corrective action within 6 Mo.
4.
November 20, 1989:
STP V-15 performed during 1R3 verifies individually full flow through SI-1-8900A through D,
SI-1-8819A through D, and SI-8905A through D.
5.
April 6, 1990:
STP V-15 performed during 2R3 verifies individually full flow through SI-2-8900A through D and V-4A performed on SI-2-8819A through D,
SI-2-8905A through D.
6.
May 24, 1990:
Discovery date.
Review of STP V-18 by System Engineering.
7.
June, 1990:
System Engineerir.g training class on IST and GL 89 requirements.
8.
March 8 & 9, 1991:
STP V-15 performed during 1R4 verifies individually full flow through SI-1-8900A ' through D,
SI-1-8819A through D,
and SI-1-8905A through D.
9.
STP V-4A and V-15 were run during 2R4.
It was judged that STP V-4A was not able to be qualified 91NCRWP\\91TNN048.PGD Page 3 of 12
i e
+
NCR DCO-91-TN-N048 November--7, 1991-l to satisfy the " alternate means" criteria required
~
by GL 89-04, Attachment 1, for all flow conditions.
D.
Other systems or secondary functions affected:
None.
E.
Method of discovery:
i The failure to test' the check' valves.according to the requirements of GL 89-04 was discovered ~ incidentally,.
during a discussion of the scope of STP V-18, Which was being circulated for cross-discipline review.
F.
Operator actions:
None.
G.
Safety. system responses:
None.
III. Cause of the problem:
A.
Immediate cause:
Failure to identify the requirement to individually -
verify the full stroke of the subject valves - during a -
review of the IST program plan against GL 89-04.
B.
Root Cause:
b
.m m'
Personnel error because the responsible personnel did not recognize the need to individually verify the full stroke open of the subject valves in accordance with :(IAW)
Position 1 of GL 89-04.
C.
Contributing-causes:
1 1.
Personnel error due to lack of understanding of-GL' 89-04 requirements by responsible' personnel.
2.
Confusion of two corrective -actions of NCR DCO-89-TN-N049; Review of IST program plan versus the' design a.
basis of check valves and 91NCRWP\\91TNN048.PGD Page 4 of 12 i
h
~...
4 a.
NCR DCO-91-TN-N048 November 7, 1991 b.
Review of the 'IST program plan versus the-requirements'of GL 89-04.
IV.
Analysis of the problem:
A.
Safety Analysis:
For Unit 1, through the performance'of STP V-15 during 1R4, the subject valves were individually verified to sufficiently stroke open to meet the
~ required post-accident flow rates.
For Unit 2, through the performance of STP V-15'during 2R3, valves SI-8900A through D were individually verified to stroke open ' sufficient to pass the required flow rates.
During 2R3 valves SI-8905A post-accident through D and SI-8819A through D werd,erified to fully v
stroke open during STP V-15.
STP V-4A was performed during 2R3 with.' acceptable results. NECS has reviewed the 2R3 STP V-4A test results and concluded that with the flow rates-observed, each check valve passed.at least the required ~ accident flow rates.
NECS found that a decreased flow rate in one loop would tend to increase the flows in..the other three loops.
However,' with the flow rates observed in 2R3, the individual loop flow rates could not have~been below the required minimum loop flows. Also, the 2R4 STP V-15 test results confirmed that the check valves were not degraded and each passed more than the required minimum flow l
rates.
I B.
Reportability:
1.
The described condition represents a
plant nonconformance IAW QAP-15.B, Section 2.1.8.
2.
This event was reviewed IAW 10 CFR 50.72, 10 CFR 50.73, guidance provided in NUREG 1022 and determined not to be' reportable.
3.
Reviewed IAW NUREG 0302 and determined not to be reportable under 10 CFR 21.
4.
This event was determined not to be reportable IAW 10 CFR 50.9 because the event as the ' described l
91NCRWP\\91TNN048.PGD Page 5 of 12
s NCR 3CO-91-TN-N048 November 7, 1991 condition does not have a significant-implication for public health and safety or common defense and security.
5.
This event does not require a network entry.
V.
Corrective Actions A.
Immediate Corrective Actions:
None required.
B.
Investigative Actions:
1.
System Engineering to run STP V-4A in conjunction with STP V-15 during 2R4, record additional data, and tvaluate the data.
RESPONSIBILITY:
C. Portney ECD:
COMPLETE DEPARTMENT:
System Engineering Tracking AR:
A00232321.AE #-03 STATUS:
INITED 2.
Based on the results of STP V-15 and V-4A, determine the course of
- action, i.e.,
relief request from GL 89-04 or in house documentation.
RESPONSIBILITY:
C. Pendleton-ECD:
COMPLETE DEPARTMENT:
System Engineering Tracking AR:
A00232321 AE # 04 3.
Research the industry for other methods to-i functionally test check valves, ari forward the information to C.
Pentleton.
RESPONSIBILITY: J.
Portney ECD:
COMPLETE DEPARTMENT:
System Engineering Tracking AR:
A00232321 -AE # 05 i
STATUS:
INITED.
C.
Corrective Actions to Prevent Recurrence:
~
1.
System engineering will provide additional training regarding the requirements of the IST program and the specific requirements contained in GL 89-04.
91NCRWP\\91TNN048.PGD Page 6 of 12-g---s-ihn
a NCR DCO-91-TN-N048 November e,
1991 RESPONSIBILITY:
M.
Burgess ECD:
COMPLETE DEPARTMENT:
System Engineering Tracking AR:
A0232321, AE # 02 Outage Related?
No JCO Related?
No NRC Commitment?
No CMD Commitment?
No 3.
Program and procedures will be revised to measure the individual loop flow rate.
(Note - Per TRG of 02/07/92 reference to program revision (s) deleted).
Responsibility:
Jeff Portney ECD:
COMPLETE Department:
PTET Tracking AR:
A0232321 AE # 06 Outage Related?
No JCO Related?
Po NRC Commitment?
No CMD Commitment?
No VI.
Additional Information A.
Failed Components:
None.
B.
Previous Similar Events:
DCO-89-TN-N049 described a plant condition where the containment spray system check valves were not leak tested per ASME Section XI.
Corrective action taken regarding this event required a review of the IST program with respect to GL 89-04.
This corrective action failed to identify the above described condition.
DCO-91-TN-N026 described normally closed check valves that have redundant safety-related functions in the reverse-flow direction during post-LOCA racirculation:
however, these check valves were not being reverse flow In Service Tested.
Corrective actions included a review of all systems for conformance to (a) design criteria, l
and (b) GL 89-04, l
C.
Operating Experience Review:
1.
NPRDS:
Not applicable.
l 91NCRWP\\91TNN048.PGD Page 7 of 12
4
,i 1
)
NCR DCO-91-TN-N048-November 7,-1991 4
2.
NRC Information Notices,' Bulletins, Generic Letters:
'" Guidance on' Developing ~
~
Acceptable In Service Testing Programs,"^ dated' April 3, 1989.-
3.
Not' applicable.
D.
Trend Code:
The responsible department is ' system engineering, and the root cause is personnel error, lack of mental' attention-(cause code ES-0A3).
1 E.
Corrective Action Tracking:
The tracking action request.is A0232321.
F.
Footnotes and Special Comments:
None.
G.
Prudent Actions;
- 1..
System engineers will be r.equested to perform a review of the IST program forL their. systems for~.
compliance with Generic - Letter. 89-04, following
- training, and to document any. _ discrepancies on AR's.
Responsibility:
C.
Pendletun ECD:
COMPLETE H.
References:
1.
Technical Spec 1fication 4.0.5.
2.
Initiating Action Request A0232119.
3.
AC V-4A,
" Acceptance Criteria for the Functional Testing of.the ECCS Check Valves," dated September 10, 1984.
4.
NRC Generic Letter 89-04, " Guidance on Developing Acceptable In Service Testing Program," dated. April' 3,
1989 91NCRWP\\91TNN048.PGD Page 8 of 12 i
i
4 I
NCR.DCO-91-TN-N048
' November 7,.1991 4
I 5.
Reportability discussion for DC1-91-TN-N048, dated l
June 3, 1991-(by John Arhar of NSARA).
I.
TRG Meeting Minutes:
j On May 30, 1991, the TRG convened ~and considered the i
circumstances described-in this-NCR.
The TRG' reviewed PG&E's position regarding GL 89-04 and-determined that although DCPP is a Table 2 plant and no written response 4
was required, the requirement to' perform.a formal review-j of the IST program was. applicable.
The TRG determined-l that this event was not reportable'since the_ Technical Specifications was met on the basis that STP-V-15 and/or i
STP V-4A. verified that. the subject. valves were individually stroke open to meet the. requirements'of the j
post-accident flow rates.
1
)
On June 3, 1991, the TRG-reconvened and considered the i
reportability determination developed by John Arhar.
j The basis ~ calls for a header flow greater than the cumulative loop' safety function flow which is balanced (STP V-15) such that a meacured difference in header flow j
would occur prior-to failure to verify " full flow" through the check valve as defined in GL 89-04..
i j
Based upon considerations documented in-GL 89-04 which i
allow Table 2 plants to operate under their approved SER i
conditions (which may be slightly different from GL conditions) but recommends that such plants " enhance j
their programs," PG&E concluded:-
1 1.
The review that PG&E performed as recommended-for Table 2 plants was not complete and the corrective action taken for the previous NCR was also.not
]
complete.
{
2.
Adequate coincidental testing performed during the j
time period assured f all valve stroking. (documented i
}
1 Based upon the above items the TRG concluded this problem is not reportable, acceptable testing as required-by the j
IST plan was performed and the basis existed to. support the tests and conclusions.
The TRG also determined that the problem is being-documented by this NCR and the recommendations of GL 89-04 are being implemented as documented in Section V, Corrective Actions.
91NCRWP\\91TNN048.PGD Page 9 of 12
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NCR.DCO-91-TN-N048 2
November 7, 1991 On September 20, 1991 the TRG reconvened and considered the following items:
j J
1.
Review of the event.-
2.
Discussed the Root Cause and relief of GL 89-04.
3.
Run both V-15 and V-4A tests in parallel.during 4
2R4. Change V-4 A if the test results show it-is required. ~Otherwise, obtain. relief from GL 89-04.
4.
Pole other utilities in the industry to-find out what are they doing.
I 5.
If no relief request is. warranted,~ document the method of testing these ' valves with' combined headcr flow in the IET program:as_follows:
a.
First Step:-Run the.two' tests in parallel and.
take the data.
b.
Second Step:
Vary the system resistance slightly to verify.that a change in one leg.
will be seen in-combined header flow.
c.
System Engineering.to run the tests' and analyze the. additional data.
i 6.
The following three investigative; actions were establisned:
1 a.
System Engineering. to run STP-V-4 A in conjunction with STP V-15 during 2R4, record additional data,
~
and evaluate the data.
1 RESPONSIBILITY:
C.
Portney ECD:
COMPLETE-R l
b.
Based on the results.of STP V-15-and.V-4A, determine.the course of action, i.e.,: relief-request from GL 89-04 or_ in house documentation.
RESPONSIBILITY:-C. Pendleton ECD:
COMPLETE c.
Research the industry for other. methods to functionally test check valves, and forward the'information to C.
Pentleton.
RESPONSIBILITY:
J. - Portney ~ ECD:
COMPLETE 91NCRWP\\91TNN048.PGD Page 10 of 12 1
- --m.1
NCR DCO-91-TN-N048 l,
Novembeu 7,
1991 i
Meeting minutes of 11/07/91 l
On November 7, 1991, the TRG reconvened and considered I
the following items:
1.
Review of the V-15 and V-4A test results conducted during 2R4.
l 2.
The following items were discussed:
a.
Flow rate sensitivity to degradation when comparing the heador flow to the Tech Spec individual loop flow rate. Initially STP V-4A was believed to be an accel taole method to demonstrate check valve performance (an IST requirement) and identify a
small flow.
restriction in the individual flow loop (as required by V-15 criteria).
But later, in comparison to STP V-15 flow measurements taken during 2R3 and 2R4 testing, highly accurate correlations between loop flow variations and total flow were not achieved.
Analysis of the 2R3 STP V-4A flow was required to determine if each valve passed the required flow.
Performance of STP V-4A alone cannot demonstrate in every case that each check valve passed sufficient flow.
Therefore, the test program should be changed to measure individual loop flows IAW GL 89-04.
b.
During 1R4, through the performance of STP V-15, the subject valves were individually verified to stroke sufficiently open to meet the requirements of the post-accident flow rate.
c.
The need to look at individual loop flow rate against degraded flow.
d.
Trojan, Sequoia and Commanche Peak, perform a i
V-15 test every outage.
3.
The following corrective actions were initiated:
a.
System Engineering will provide additional training regarding the requirements of the IST program and the specific requirements 91NCRWP\\91TNN048.PGD Page 11 of 12 i
NCR DCO-91-TN-N048 November 7, 1991' contained in GL 89-04.
b.
Program and procedures will be revised to measure the individual loop flow rate.
4.
A prudent action was established to request. the system engineers to perform a review of.the IST program for their systems for ' compliance with j
Generic Letter 89-04, following training and to l
document any discrepancies'on AR's.
On February 7, 1992, the TRG reconvened and reviewed; 1.
The NECS engineering evaluation of STP V-4A for-2R3-l data which documents an acceptable full flow test.
\\
.2.
Further definition that' procedural.changea'made to:
STPs V-15'and V-4A are adequate' resolution of.the problem and - further_ programmatic changes are not required ' because plant administrative procedures
\\
adequately address future IST program changes.
u 3.
This NdR> ECD may be changed to 03/31/92.
The TRG unanimously approved the NCR 'as corrected'2/7/92.
J.
Remarks:
None.
~s
.m, 91NCRWP\\91TNN048.PGD Page 12 of 12-
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