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{{Adams | |||
| number = ML20141A247 | |||
| issue date = 06/13/1997 | |||
| title = Insp Rept 50-382/97-13 on 970602-04.Violations Noted.Major Areas Inspected:Ability of Containment Isolation Valve to Perform Intended Function | |||
| author name = | |||
| author affiliation = NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) | |||
| addressee name = | |||
| addressee affiliation = | |||
| docket = 05000382 | |||
| license number = | |||
| contact person = | |||
| document report number = 50-382-97-13, NUDOCS 9706200191 | |||
| package number = ML20141A226 | |||
| document type = INSPECTION REPORT, NRC-GENERATED, TEXT-INSPECTION & AUDIT & I&E CIRCULARS | |||
| page count = 14 | |||
}} | |||
See also: [[see also::IR 05000382/1997013]] | |||
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ENCLOSURE ! | |||
U.S. NUCLEAR REGULATORY COMMISSION | |||
REGION IV | |||
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Docket No.: 50-382 | |||
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License No.: NPF-38 | |||
Report No.: 50 382/97-13 ; | |||
Licensee: Entergy Operations, Inc. | |||
Facility: Waterford Steam Electric Station, Unit 3 | |||
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- Location: Hwy.18 | |||
Killona, Louisiana ; | |||
Dates: June 2 6,1997 ! | |||
Inspector: G. E. Werner, Project Engineer, Project Branch D | |||
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Approved By: P. H. Harrell, Chief, Project Branch D I | |||
ATTACHMENTS: | |||
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Attachment 1: Supplemental Information i | |||
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Attachment 2: Section E2.1 from NRC Inspection Report 50-382/96-24 ; | |||
Attachment 3: Task Interface Agreement (TIA) "Waterford 3 - Requirements for | |||
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the Capability of Containment isolation Valves' to Close to Maintain ! | |||
Containment Integrity" (TAC M97234) ' | |||
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9706200191 97061 | |||
PDR ADOCK 05000302 | |||
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EXECUTIVE SUMMARY | |||
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Waterford Steam Electric Station, Unit 3 i | |||
NRC Inspection Report 50-382/97-13 | |||
. This special inspection was conducted to review the ability of containment isolation valves | |||
3 | |||
to perform their intended safety function. This issue was identified as Unresolved ' | |||
Item 50-382/9624-03 in NRC Inspection Report 50-382/96-24. Section E2.1 of the report ; | |||
is provided as Attachment 2 to this report. To obtain resolution of this issue, Task ' | |||
interface Agreement (TIA) 96TIA017, "Waterford 3 - Requirements for the Capability of ' | |||
Containment isolation Valves to Close to Maintain Containment Integrity," was issued by- | |||
the NRC's Office of Nuclear Reactor Regulation (NRR) to provide the requirements that l | |||
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specifically apply to Waterford 3. The TIA is provided as Attachment 3 to this report. ; | |||
Enoineeri_n_g [ | |||
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The licensee failed to provide a closed capability for the containment spray header | |||
and component cooling water to containment fan cooler containment isolation | |||
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valves. The failure to maintain containment isolation valves in an operable status is | |||
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an apparent violation of Technical Specification 3.6.3 (Section E8.1). : | |||
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The Updated Final Safety Analysis Report stated that containment isolation valves | |||
have the capability to be closed from the control room to isolate a faulted I | |||
engineered safety feature system. However, the containment spray header and | |||
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component cooling water to containment fan cooler containment isolation valves i | |||
could not be closed with a safety injection actuation signal present. The failure to | |||
perform a safety evaluation is an apparent violation of 10 CFR 50.59 ; | |||
ISection E8.1). | |||
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; Report Details | |||
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E8 Miscellaneous Engineering issues | |||
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E.8.1 IClosed) Unresolved item 50-382/9624-03: Requirement for a closed safety ! | |||
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function for containment isolation valves. Previously, the inspectors identified that ' | |||
the licensee designated certain engineered safety features containment isolation | |||
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valves as not having a closed safety function and, as a result, the valves were not | |||
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provided with the capability to be closed. During the inspection, the inspectors | |||
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concluded that the valves were required to have a closed safety function and were | |||
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required to be capable of being closed under all conditions in case of a line or | |||
system malfunction. The licensee expressed the position that the plant was ; | |||
licensed without requiring the closed capability for the valves and, therefore, the | |||
containment isolation valve design was acceptable. Based on the licensee's | |||
contention, this issue was identified as unresolved pending a response to | |||
TIA 96TIA017 by NRR. See Attachment 2 for the details provided in NRC | |||
inspection Report 50-382/96-24. | |||
The response to TIA 96TIA017 stated, in part, that containment isolation is always | |||
considered a safety function and all containment isolation valves are required to ; | |||
have a closed safety function (refer to Attachment 3 for the complete i | |||
TIA response). The NRR technical staff acknowledged in the TIA that the system i | |||
safety function (e.g., containment spray) takes priority over the containment ; | |||
isolation function; however, when the system is no longer able to perform its | |||
primary safety function, then containment isolation takes priority. | |||
Technical Requirements Manual Table 3.6.2 lists Valves CS-125A(B), CC-807A(B), | |||
CC-808A(B), CC-822A(B), and CC-823A(B) as containment isolation valves | |||
. | |||
applicable to Technical Specification 3.6.3. Based on previous inspections and ! | |||
discussions with licensee personnel, it was established that these valves could not | |||
perform their containment isolation safety function because: (1) procedures were | |||
not provided that allowed the installation of electricaljumpers to permit closure of | |||
the valves with a safety injection actuation signal present, and (2) the air | |||
accumulator assemblies for Valves CC-807A(B), CC 808A(B), CC-822A(B), and CC- | |||
823A(B) were not capable of supplying the air required to shut the valves. The | |||
failure to have operable containment isolation valves capable of providing | |||
containment isolation is an apparent violation of Technical Specification 3.6.3 | |||
(50-382/9713-01). l | |||
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Updated Final Safety Analysis Report Section 6.2.4.1.2, " Criteria for Isolation of ! | |||
Fluid Systems Penetrating the Containment," stated that each penetration line shall ' | |||
contain one isolation valve outside containment that shall be capable of either j | |||
cutomatic or remote manual operation or locked closed. Further, Section 6.2.4.1.2 ' | |||
stated that remote manual valves have the capability to be shut to isolate a faulted | |||
engineered safety feature system and that, " Valves isolating penetrating lines j | |||
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serving engineered safety feature systems are not closed automatically by the CIAS | |||
Icontainment isolation actuation signal], but have the ability to be closed by remote | |||
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manual operation from the main control room, thereby, isolating any engineered | |||
safety feature system which malfunctions." However, the licensee operated the | |||
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plant, since construct;on, without the capability to shut the above listed | |||
containment isolation valves when required. The failure to perform a written safety | |||
evaluation that provides the basis for the determination that the change does not | |||
involve an unreviewed safety question is an apparent violation of | |||
10 CFR 50.59(b)(1) (50-302/9713-02). | |||
V. Manaaement Meetinos | |||
. X1 Exit Meeting Summary | |||
' The senior resident inspector presented the inspection results to members of | |||
licensee management on June 5, i997. The licensee acknowledged the findings | |||
< presented. | |||
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The inspector asked the licensee whether any materials examined during the | |||
inspection should be considered proprietary. No proprietary information was | |||
identified. | |||
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, _ . . . _ . . . _ _ . _ . _ . _ . . _ _ _ _ . _ . _ _ _ _ _ . . . _ _ _ _ _ _ . _ . _ _ _ _ _ _ . - _ _ _ _ . . _ . _ . . _ | |||
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ATTACHMENT 1 | |||
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< SUPPLEMENTAL INFORMATION | |||
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t PARTIAL LIST OF PERSONS CONTACTED | |||
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Licensee | |||
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INSPECTION PROCEDURES USED | |||
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j IP 92903 Followup - Engineering | |||
ITEMS OPENED AND CLOSED | |||
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Open i | |||
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50-382/9713-01 eel An apparent violation of Technical Specification 3.6.3 for | |||
failure to maintain containment isolation valves operable | |||
50-382/9713-02 eel An apparent violation of 10 CFR 50.59 for failure to | |||
perform a safety evaluation associated with a lack of | |||
closure capablity for numerous containment isolation | |||
valves. | |||
Closed | |||
50-382/9624-03 URI Requirement of a closed safety function for containment | |||
isolation valves | |||
LIST OF ACRONYMS USED | |||
eel escalated enforcement item | |||
ESF engineered safety feature | |||
TIA task interface agreement | |||
URI unresolved item | |||
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ATTACHMENT 2 | |||
Excerpt from inspection Report 50-382/96 24 | |||
E2.1 | |||
Containment Sorav Header and CCW to Containment Fan Cooler Containment | |||
isolation Valves | |||
a. Inspection Scone (37551) | |||
The inspectors reviewed licensee correspondence with the NRC, licensee internal | |||
correspondence, the Safety Evaluation Report, the Standard Review Plan, the | |||
UFSAR, General Design Criteria (GDC) 56 and 57, and numerous regulatory | |||
guidance documents to determine the applicability of a closed safety function for | |||
the containment isolation valves, associated with containment spray and CCW | |||
systems. | |||
b. Observations and Findinos | |||
b.1 Containment Spray isolation Valves CS-125A(B) - | |||
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Containment spray lines penetrate containment through Penetrations 34 and 35. | |||
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Technical Requirements Manual Table 3.6-2, "Contenment isolation Valves," lists I | |||
containment isolation vahres that are applicable to Technical Specification 3.6.3, i | |||
" Containment isolation Valves." For Penetration 34, Valves CS-125A and CS-128A | |||
were listed as containment isolation valves. For Penetration 35, Valves CS-1258 , | |||
and CS-1288 were listed as containment isolation valves, in addition, UFSAR Table 1 | |||
6.2-32, " Containment Penetrations and Isolation Valves," list Valves CS-125A(B) as I | |||
one of the two containment penetration isolation valves. | |||
Valves CS-125A(B) are air-operated gate valves that fail open on loss of IA. | |||
Nonsafety-related IA is the normal air supply with backup air supplied by | |||
safety-related air accumulators. Valves CS-125A(B) receive an open signal on a ! | |||
containment spray actuation signal. | |||
The containment spray system is classified as an open system ';3ide containment. | |||
GDC 56 specifies acceptable means to meet the required containment isolation | |||
provisions for systems open to containment atmosphere. The inspectors | |||
determined that the containment isolation provisions for containment spray headers | |||
were satisfied in accordance with GDC 56 by having one automatic valve (Check | |||
Valves CS-128A(B)) inside containment and one remote manual isolation valve | |||
(Valves CS-125A(B)) located outside containment. Remote manual valves located | |||
outside containment are allowed by American National Standard (ANSI) N271-1976, | |||
" Containment isolation Provision for Fluid Systems," Section 3.6, "Other Defined | |||
Basis," Subsection 3.6.3, " Remote Manual Valves," provided provisions are made | |||
to detect possible failure of the fluid lines inside and outside containment and the | |||
capability is maintained to remote manually isolate these lines. | |||
For Valves CS-125A(B), the control circuitry was designed in such a manner that, | |||
once a containment spray actuation signal exists, the valves cannot be shut until | |||
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the containment spray actuation signal clears; however, the circuitry could be | |||
jumpered to allow closure of the valve in the malfunctioning containment system | |||
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train. This is significant since an alternate isolation valve cannot be closed until 6 | |||
hours after a LOCA because of high radiation levels in the minus t' foot valve | |||
enclosure bay area of the reactor auxil!ary building. | |||
b.2 CCW to Containment Fan Cooler Containment Isolation Valves | |||
CCW to the containment fan cooler lines penetrate containment through | |||
Penetrations 15 through 22. Technical Requirements Manual Table 3.6-2 lists the | |||
CCW to containment fan cooler valves as containment isolation valves applicable to | |||
Technical Specification 3.6.3 Further, UFSAR Table 6.2.32 listed Valves | |||
CC-807A(B), -808,A(B), -822A(B), and -823A(B) as containment isolation valves. | |||
The CCW air-operated, betterfly CCW to containment fan cooler isolation valves fail | |||
open on loss of IA. Nonsafety-related IA is the normal air supply with backup air | |||
being supplied by safety-related air accumulators. | |||
The CCW to containment fan cooler lines form closed systems inside containment. | |||
GDC 57 specifies that for closed systems that penetrate containment, the lines shall | |||
have at least one containment isolation valve which is either automatic, or locked | |||
closed, or capable of remote manual operation that is located outside containment. | |||
The inspectors determined that the containment isolation provisions were satisfied | |||
for the CCW to containment fan cooler penetration lines by having a closed CCW | |||
system inside containment and remote manual valves located outside containment. | |||
Once a safety injection actuation signal exists, the control circuitry for the | |||
containment fan cooler isolation valves does not allow the CCW to containment fan | |||
cooler isolation valves to be shut until the safety injection actuation signal clears; ; | |||
however, the circuitry could be jumpered around to allow closure of the valve in the ' | |||
malfunctioning CCW system train. | |||
b.3 Common Containment isolation Requirements | |||
Regulatory Guide 1.141, " Containment isolation Provisions for Fluid Systems," April | |||
1978, endorsed the use of ANSI N271-1976, with some exceptions not applicable | |||
to the affected valves. ANSI N-271 approved containment configurations required | |||
to meet GDC 56 and 57. Safety Evaluation Report, Section 6.2.4, " Containment | |||
Isolation System," stated, in part, that the containment isolation provisions met the | |||
requirements of GDC 54,55,56, and 57, and satisfied the guidance of Regulatory | |||
Guide 1.141. | |||
UFSAR Section 6.2.4.1.2, " Criteria for Isolation of Fluid Systems Penetrating the | |||
Containment," required that each penetration line contain one isolation valve outside ) | |||
; | |||
containment that shall be capable of either automatic or remote manual operation or J | |||
locked closed. Further, Section 6.2.4.1.2 required that remote manual valves have ' | |||
the capability to be shut to isolate a faulted ESF system and that " Valves isolating | |||
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penetrating lines serving engineered safety feature systems are not closed | |||
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automatically by the CIAS [ containment isolation actuation signal], but have the ' | |||
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ability to be closed by remote manual operatior, f,om the main control room, thereby ' | |||
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isolating any engineered safety feature system which malfunctions." The inspectors | |||
' determined that UFSAR Section 6.2.4.1.2 was consistent with regulatory | |||
requirements. | |||
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j b.4 Licensee Position for ESF System Containment isolation Valves ' | |||
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Throughout the inspection and during the exit meeting, licensee management | |||
j maintained the following positions: | |||
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Based on the original design and licensing of the plant, the subject | |||
valves were considered containment isolation valves. | |||
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All regulatory requirements for containment isolation were satisfied. | |||
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The subject valves did not have a closed safety function. | |||
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' The NRC's preliminary position that the valves have a closed safety ; | |||
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function is a backfit. | |||
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No testing was required to demonstrate the ability of the | |||
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accu-ulators to provide backup air to stroke the subject valves in the | |||
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closed direction and to maintain the a closed since the valves did not | |||
i have a closed safety function. | |||
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The licensee maintained that Valves CS-125A(B) never had a closed safety function | |||
} as discussed in various letters between the utility and the NRC. The licensee | |||
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contended that Letter W3P84-0577, dated March 16,1984, informed the NRC that | |||
a water barrier would be maintained in the containment spray system piping. , | |||
j Discussions with various licensing personnel indicated that, based upon this letter, | |||
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the licensee determined that Valves CS-125A(B) did not have a closed safety | |||
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function and that containment integrity would be maintained with the water barrier , | |||
" in the containment spray system because it formed a closed system outside ' | |||
containment. | |||
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{ The inspectors noted that Letter W3P84-0577 was used to justify relief from | |||
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performing Appendix J leak rate testing on various containment isolation valves, i | |||
p including Valves CS-125A(B). Enclosure 1, of the letter, indicated that a water | |||
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barrier could be maintained in the containment spray system piping for 30 days ! | |||
assuming Valves CS-125A(B) remained closed. However, the valves fail open on l | |||
} loss of IA and cannot be closed without using some type of backup air. | |||
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From 1989 to 1994, internal licensee correspondence documented the safety | |||
function (both open and closed) for valves CS-125A(B). In 1994, the licensee ' | |||
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concluded the valves had no closed safety function and discontinued accumulator | |||
testing in August 1994 (last test completed March 8,1994 under Work | |||
Authorization 01121332). This was documented in a 10 CFR 50.59 screening | |||
titled " Revision 1 to STA-001-005, Leakage Testing of Air and Nitrogen | |||
Accumulators Safety-Related Valve." The licensee justified not testing CS-125A(B) | |||
because, " credit may be taken for containment spray train isolation using CS- | |||
117A(B) [stop check valve located outside containment] and CS-118A(B) (normally | |||
closed manual recirculation valve to tha RWSP]. The CS-125A(B) accumulator tests | |||
are therefore not required." | |||
The licensee also maintained that the CCW to containment fan cooler isolation | |||
valves did not have a closed safety function. Various licensee documents justified | |||
this position by stating that the CCW system is classified as a Seismic Category 1, | |||
Safety Class 3, closed system whose failure does not have to be postulated during | |||
a loss of coolant accident. Therefore, the containment isolation barrier would be | |||
the CCW piping system inside containment. | |||
During the inspection and at the exit, licensee management stated that they | |||
believed the original design was consistent with regulatory requirements. Licensee | |||
management contended that the NRC knew that the containment spray header and | |||
CCW to containment fan cooler containment isolation valves could not be shut once | |||
a containment . spray actuation signal or safety injection actuation signal existed and, | |||
therefore, licensed the plant with an approved containment penetration design. | |||
Further, management indicated that the requirement for these valves to have a | |||
closed safety function was a change in previous NRC position, thereby constituting | |||
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a backfit. | |||
b.5 Licensee and NRC Management Conference Call | |||
On October 25,1996, Region IV and NRR personnel, including NRC management, | |||
held a conference call with the licensee to understand the licensee's position. | |||
During this call, NRC agreed to allow the licensee time to submit a letter detailing | |||
the licensing basis for the subject containment isolation valves. In the interim, the | |||
Vice President, Operations, committed to performing actions to ensure the isolation | |||
capacity of the associated penetrations while NRC evaluated the licensee's position. | |||
The commitment involved testing of each containment isolation valve accumulator | |||
and establishing procedural guidance to enable closure of the valves from the | |||
control room for a line or system fault during accident conditions. | |||
The ten containment isolation valve accumulators and actuating systems were leak | |||
tested satisfactorily by November 8,1996. Valves CS-125A(B) passed without any | |||
rework. All of the CCW to containment fan cooler isolation valves required | |||
extensive rework. Numerous leaks were repaired on fittings, solenoid valves, and | |||
actuating mechanistas. The leakage would have prevented the ability to maintain | |||
the valves closed, if containment isolation was required. | |||
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Independent of the licensee submittal, Region IV submitted Task interface | |||
Agreement 96TIA017, dated November 13,1996, requesting NRR to review the | |||
regulatory requirements for isolation and closure capability for the containment | |||
isolation valves. Pending NRR's review of Task Interface Agreement 96TIA017, the | |||
operability requirements of the containment spray and CCW to containment fan | |||
cooler isolation valves are identified as an unresolved item (382/9624-03). | |||
c. Conclusions | |||
From review of regulatory requirements and discussions with NRR Containment | |||
System Branch personnel, it appeared that Valves CS-125A(B) and the CCW to | |||
containment fan cooler containment isolation valves have a closed safety function. | |||
Specifically, the valves are required to have the capability to close in case of a line , | |||
or system malfunction in order to maintain containment integrity under all I | |||
conditions. However, because of the position expressed by the licensee, Region IV | |||
has requested a formal review of the regulatory requirements from NRR. | |||
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; ATTACHMENT 3 | |||
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April 22,1997 | |||
MEMORANDUM TO: Thomas P. Gwynn, Director , | |||
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Division of Reactor Projects, RIV i | |||
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4 FROM: William D. Beckner, Director /S/ ORlG SIGNED BY: JHall for | |||
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Project Directorate IV-1 | |||
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Division of Reactor Projects lil/IV 4 | |||
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! SUBJECT: | |||
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TASK INTERFACE AGREEMENT (TIA)- WATERFORD 3 - REQUIREMENTS i | |||
' FOR THE CAPABILITY OF CONTAINMENT ISOLATION VALVES TO CLOSE I | |||
i TO MAINTAIN CONTAINMENT INTEGRITY (TAC NO. M97234) | |||
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in a memorandum dated November 13,1996, from J. E. D ,.. to W. D. Beckner, Region IV | |||
3 | |||
requested the Office of Nuclear Reactor Regulation (NRR) to review the licensee's position | |||
j on compliance with the general design criteria for dual function (i.e., open safety function | |||
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on a safety injection actuation signal and/or containment function to isolate the | |||
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containment) air-operated containment penetration valves. On March 18,1997, the NRR | |||
{ and Region IV staff met with the licensee to discuss containment isolation design and | |||
: licensing basis for Waterford Steam Electric Station, Unit 3. While some more discussion | |||
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with the licensee regarding the long term resolution of the detailed design issues is | |||
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required, the NRR has determined that the staff position is clear as discussed below. | |||
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Before addressing the specific designs, one needs to understand the roles of a system | |||
} safety function and containment isolation function. In general, a system which penetrates | |||
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containment has an important role to play in the overall operation of the plant. Some | |||
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perform a safety function in a pre / post loss of coolant accident (LOCA) manner while | |||
; | |||
others are important to the overall operation of the plant. In either case, however, the | |||
i | |||
requirement to perform a containment isolation function is the same. Containment | |||
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isolation is always considered to be a safety function. The only remaining question is | |||
{ when the isolation function needs to be performed. | |||
i | |||
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i Let us reverse the order and first discuss the role of the containment isolation valves for a i | |||
nonsafety system. For this system class, it is normally assumed that the need for the l | |||
; | |||
system function ceases when the need for containment isolation is identified. Receipt of a ) | |||
j | |||
containment isolation signal will cause the containment isolation valves to automatically | |||
1 l | |||
actuate. This satisfies (na containment function while at the same time ending the normal | |||
j functioning of the system. | |||
1 | |||
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The safety system containment isolation philosophy is quite similar. The difference relates ! | |||
to the priority of the function. Unlike for a nonsafety system, the safety system function | |||
; | |||
does not cease when the need for containment isolation is identified. The safety function l | |||
i | |||
simply takes priority over containment isolation. As long as the system is able to provide | |||
its safety function, containment isolation should not be implemented. However, if the | |||
t ; | |||
system is not able to perform its safety function, then containment isolation becomes its I | |||
: number one priority. | |||
'2 | |||
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By having the safety system function take first priority eliminates the need for automatic | |||
containment isolation. Remote isolation is the accepted mode for this type of system. | |||
With remote isolation capability, however, comes the need to know when isolation is | |||
needed. This generally means leak detection and some means to determine system | |||
operability. | |||
Once it is determined that the safety function is not operable, containment isolation | |||
! | |||
becomes the number one priority. The operators are trained to properly isolate the system i | |||
which means closing both containment isolation valves. l | |||
1 | |||
Now, let us look at the requirements to isolate. The function must be fully safety grade. ] | |||
This means that the instrumentation, motive power, actuator, and valve must be all safety I | |||
grade, if the valve is motor operated, it should be Class ?E powered. For air power, the ' | |||
valve should either close upon loss of air supply or the supply should be considered l | |||
essential which generally implies an adequately sized accumulator that will assure valve | |||
closure for 30 days. | |||
I | |||
Therefore, for systems with a dual requirement, the valves can and probably will have a ; | |||
two position criteria. To satisfy the safety system function, the valve position should be | |||
! | |||
open. However, to satisfy the containment isolation function, valve position should be | |||
closed. To simply look at the safety system function to establish valve position meets only | |||
half of the valve requirements. Additionally, to power the valve actuator with a nonsafety | |||
air supply is unacceptable when the failure position is open since the containment isolation | |||
l | |||
function cannot be satisfied. | |||
With this brief background, one can now discuss the specific questions contained with the | |||
TIA request. _Specifically, Region IV has identified the following questions: | |||
QUESTION 1 | |||
Does the licensee comply with the requirements of Criterion 57 (i.e., do the | |||
containment spray and component cooling water containment penetration valves | |||
have a closed safety function?). In particular, are the air-operated valve | |||
accumulators required to maintain the valves closed on a loss of nonsafety related | |||
instrument air? | |||
RESPONSE | |||
The valves in question have dual requirements. For the system safety function, the | |||
valves have an open function to assure the operability of the system when needed. | |||
However, the valves also have a containment isolation function when called upon. | |||
Under this sequence, the valves have a closed function. As discussed above, the | |||
system safety function has first priority. Therefore, the fail open design is | |||
appropriate. But, the containment isolation function is equally important when the | |||
situation calls for isolation. This means that the air supply should be safety grade | |||
to minimize the times when one loses the air supply to the valvs which also loses | |||
the containment isolation function. The design needs safety accumulators to assure | |||
, | |||
. | |||
, | |||
W | |||
3- | |||
an air supply in the event of loss of nonsafety instrume it air. For this reason, it is | |||
unacceptable to have nonsafety instrument air without s safety backup system. | |||
Q UESTION 2 | |||
_ | |||
Would similar valves for containment penetrations subjr et to the requirements of | |||
Criteria 55 and 56 also have a closed safety function fc containment isolation, i | |||
even if, the position of greater safety of the valve is to open? | |||
{ | |||
i | |||
RESPONSE | |||
1 | |||
All containment isolation valves subject to the requirem nts of i | |||
1 | |||
Criteria 55 and 56 have a closed safety function. Howi ver, it is quite | |||
misleading to state that the position of greater safety ol' the valve is to | |||
open. These valves under discussion have a dual requii iment; performance of | |||
the system safety function and the containment isolatic'i function. Each function is | |||
a separate responsibility. Therefore, for the system safe ty function, the position of | |||
greater safety is open. But for the containment isolation function, the position of | |||
greater safety is closed. Since the system function has tPst priority, the valve | |||
should f ail open upon loss of air. However, since the containment isolation position | |||
of greater safety is closed, the air supply should be as reable as possible to | |||
minimize the probability of the loss of air. This is translatul to mean safety grade. | |||
QUESTION 3 | |||
{ | |||
is the licensee required to have the capability of remote manual closure of the | |||
containment penetration valves with a safety injection actustion signal and/or | |||
containment spray actuation signal present? | |||
RESPONSE | |||
The simple response is yes. The licensee is required to be able to remotely close | |||
the valve at any time during the transient. This is om'icularly irr,portant if the safety ! | |||
system has a burned in signal to stay open to mai.nai n the safety system function. | |||
The solution is to design the logic such that a switch in the control room can be | |||
actuated to override this open signal. An example of such a design can be found on | |||
the containment isolation valves connected to an external recombiner. Normally the | |||
valves are in a closed position. To allow the recombiner to become operational, | |||
these valves must be opened even though there exists a containment isolation | |||
signal. This override logic eliminates the need to jumper the connections within the | |||
control cabinet which would be necessary without this control logic. | |||
Equally important to the ability to change valve position is knowing when to initiate | |||
containment isolation. Sufficient instrumentation should be available to the operator | |||
for this purpose. This would include leak detection as well as sufficient | |||
; | |||
discrimination to determine which system is leaking. | |||
e | |||
9 | |||
._ . _ . . . . _ . | |||
, | |||
' | |||
. | |||
-4- | |||
QUESTION 4 | |||
If the answer to Question 3 is yes, are manual actions an acceptable means of | |||
meeting this requirement? | |||
RESPONSE | |||
, | |||
Manual action is an acceptable means for meeting this requirement. But, it should | |||
be remote manual and normally from the control room. | |||
With respect to the acceptability of the accumulators that exist at Waterford 3, we are | |||
, | |||
planning to discuss this issue with the licensee. We willinclude Region IV staff in all of i | |||
our future interactions with licensee on this issue. | |||
cc: C. Hehl, Ri | |||
J. Johnson, Ril | |||
J. Caldwell, Rill | |||
. | |||
! | |||
! | |||
l | |||
! | |||
l | |||
l | |||
l | |||
! i | |||
i | |||
! | |||
i | |||
i | |||
d | |||
l | |||
l | |||
}} |
Latest revision as of 15:51, 27 October 2020
ML20141A247 | |
Person / Time | |
---|---|
Site: | Waterford ![]() |
Issue date: | 06/13/1997 |
From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
To: | |
Shared Package | |
ML20141A226 | List: |
References | |
50-382-97-13, NUDOCS 9706200191 | |
Download: ML20141A247 (14) | |
See also: IR 05000382/1997013
Text
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ENCLOSURE !
U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
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Docket No.: 50-382
License No.: NPF-38
Report No.: 50 382/97-13 ;
Licensee: Entergy Operations, Inc.
Facility: Waterford Steam Electric Station, Unit 3
{
- Location: Hwy.18
Killona, Louisiana ;
Dates: June 2 6,1997 !
Inspector: G. E. Werner, Project Engineer, Project Branch D
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Approved By: P. H. Harrell, Chief, Project Branch D I
ATTACHMENTS:
Attachment 1: Supplemental Information i
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Attachment 2: Section E2.1 from NRC Inspection Report 50-382/96-24 ;
Attachment 3: Task Interface Agreement (TIA) "Waterford 3 - Requirements for
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the Capability of Containment isolation Valves' to Close to Maintain !
Containment Integrity" (TAC M97234) '
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9706200191 97061
PDR ADOCK 05000302
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EXECUTIVE SUMMARY
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Waterford Steam Electric Station, Unit 3 i
NRC Inspection Report 50-382/97-13
. This special inspection was conducted to review the ability of containment isolation valves
3
to perform their intended safety function. This issue was identified as Unresolved '
Item 50-382/9624-03 in NRC Inspection Report 50-382/96-24. Section E2.1 of the report ;
is provided as Attachment 2 to this report. To obtain resolution of this issue, Task '
interface Agreement (TIA) 96TIA017, "Waterford 3 - Requirements for the Capability of '
Containment isolation Valves to Close to Maintain Containment Integrity," was issued by-
the NRC's Office of Nuclear Reactor Regulation (NRR) to provide the requirements that l
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specifically apply to Waterford 3. The TIA is provided as Attachment 3 to this report. ;
Enoineeri_n_g [
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The licensee failed to provide a closed capability for the containment spray header
and component cooling water to containment fan cooler containment isolation
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valves. The failure to maintain containment isolation valves in an operable status is
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an apparent violation of Technical Specification 3.6.3 (Section E8.1). :
The Updated Final Safety Analysis Report stated that containment isolation valves
have the capability to be closed from the control room to isolate a faulted I
engineered safety feature system. However, the containment spray header and
component cooling water to containment fan cooler containment isolation valves i
could not be closed with a safety injection actuation signal present. The failure to
perform a safety evaluation is an apparent violation of 10 CFR 50.59 ;
ISection E8.1).
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- Report Details
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E8 Miscellaneous Engineering issues
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E.8.1 IClosed) Unresolved item 50-382/9624-03: Requirement for a closed safety !
function for containment isolation valves. Previously, the inspectors identified that '
the licensee designated certain engineered safety features containment isolation
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valves as not having a closed safety function and, as a result, the valves were not
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provided with the capability to be closed. During the inspection, the inspectors
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concluded that the valves were required to have a closed safety function and were
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required to be capable of being closed under all conditions in case of a line or
system malfunction. The licensee expressed the position that the plant was ;
licensed without requiring the closed capability for the valves and, therefore, the
containment isolation valve design was acceptable. Based on the licensee's
contention, this issue was identified as unresolved pending a response to
TIA 96TIA017 by NRR. See Attachment 2 for the details provided in NRC
inspection Report 50-382/96-24.
The response to TIA 96TIA017 stated, in part, that containment isolation is always
considered a safety function and all containment isolation valves are required to ;
have a closed safety function (refer to Attachment 3 for the complete i
TIA response). The NRR technical staff acknowledged in the TIA that the system i
safety function (e.g., containment spray) takes priority over the containment ;
isolation function; however, when the system is no longer able to perform its
primary safety function, then containment isolation takes priority.
Technical Requirements Manual Table 3.6.2 lists Valves CS-125A(B), CC-807A(B),
CC-808A(B), CC-822A(B), and CC-823A(B) as containment isolation valves
.
applicable to Technical Specification 3.6.3. Based on previous inspections and !
discussions with licensee personnel, it was established that these valves could not
perform their containment isolation safety function because: (1) procedures were
not provided that allowed the installation of electricaljumpers to permit closure of
the valves with a safety injection actuation signal present, and (2) the air
accumulator assemblies for Valves CC-807A(B), CC 808A(B), CC-822A(B), and CC-
823A(B) were not capable of supplying the air required to shut the valves. The
failure to have operable containment isolation valves capable of providing
containment isolation is an apparent violation of Technical Specification 3.6.3
(50-382/9713-01). l
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Updated Final Safety Analysis Report Section 6.2.4.1.2, " Criteria for Isolation of !
Fluid Systems Penetrating the Containment," stated that each penetration line shall '
contain one isolation valve outside containment that shall be capable of either j
cutomatic or remote manual operation or locked closed. Further, Section 6.2.4.1.2 '
stated that remote manual valves have the capability to be shut to isolate a faulted
engineered safety feature system and that, " Valves isolating penetrating lines j
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serving engineered safety feature systems are not closed automatically by the CIAS
Icontainment isolation actuation signal], but have the ability to be closed by remote
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manual operation from the main control room, thereby, isolating any engineered
safety feature system which malfunctions." However, the licensee operated the
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plant, since construct;on, without the capability to shut the above listed
containment isolation valves when required. The failure to perform a written safety
evaluation that provides the basis for the determination that the change does not
involve an unreviewed safety question is an apparent violation of
10 CFR 50.59(b)(1) (50-302/9713-02).
V. Manaaement Meetinos
. X1 Exit Meeting Summary
' The senior resident inspector presented the inspection results to members of
licensee management on June 5, i997. The licensee acknowledged the findings
< presented.
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The inspector asked the licensee whether any materials examined during the
inspection should be considered proprietary. No proprietary information was
identified.
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ATTACHMENT 1
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< SUPPLEMENTAL INFORMATION
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t PARTIAL LIST OF PERSONS CONTACTED
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Licensee
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INSPECTION PROCEDURES USED
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j IP 92903 Followup - Engineering
ITEMS OPENED AND CLOSED
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50-382/9713-01 eel An apparent violation of Technical Specification 3.6.3 for
failure to maintain containment isolation valves operable
50-382/9713-02 eel An apparent violation of 10 CFR 50.59 for failure to
perform a safety evaluation associated with a lack of
closure capablity for numerous containment isolation
valves.
Closed
50-382/9624-03 URI Requirement of a closed safety function for containment
isolation valves
LIST OF ACRONYMS USED
eel escalated enforcement item
ESF engineered safety feature
TIA task interface agreement
URI unresolved item
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ATTACHMENT 2
Excerpt from inspection Report 50-382/96 24
E2.1
Containment Sorav Header and CCW to Containment Fan Cooler Containment
isolation Valves
a. Inspection Scone (37551)
The inspectors reviewed licensee correspondence with the NRC, licensee internal
correspondence, the Safety Evaluation Report, the Standard Review Plan, the
UFSAR, General Design Criteria (GDC) 56 and 57, and numerous regulatory
guidance documents to determine the applicability of a closed safety function for
the containment isolation valves, associated with containment spray and CCW
systems.
b. Observations and Findinos
b.1 Containment Spray isolation Valves CS-125A(B) -
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Containment spray lines penetrate containment through Penetrations 34 and 35.
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Technical Requirements Manual Table 3.6-2, "Contenment isolation Valves," lists I
containment isolation vahres that are applicable to Technical Specification 3.6.3, i
" Containment isolation Valves." For Penetration 34, Valves CS-125A and CS-128A
were listed as containment isolation valves. For Penetration 35, Valves CS-1258 ,
and CS-1288 were listed as containment isolation valves, in addition, UFSAR Table 1
6.2-32, " Containment Penetrations and Isolation Valves," list Valves CS-125A(B) as I
one of the two containment penetration isolation valves.
Valves CS-125A(B) are air-operated gate valves that fail open on loss of IA.
Nonsafety-related IA is the normal air supply with backup air supplied by
safety-related air accumulators. Valves CS-125A(B) receive an open signal on a !
containment spray actuation signal.
The containment spray system is classified as an open system ';3ide containment.
GDC 56 specifies acceptable means to meet the required containment isolation
provisions for systems open to containment atmosphere. The inspectors
determined that the containment isolation provisions for containment spray headers
were satisfied in accordance with GDC 56 by having one automatic valve (Check
Valves CS-128A(B)) inside containment and one remote manual isolation valve
(Valves CS-125A(B)) located outside containment. Remote manual valves located
outside containment are allowed by American National Standard (ANSI) N271-1976,
" Containment isolation Provision for Fluid Systems," Section 3.6, "Other Defined
Basis," Subsection 3.6.3, " Remote Manual Valves," provided provisions are made
to detect possible failure of the fluid lines inside and outside containment and the
capability is maintained to remote manually isolate these lines.
For Valves CS-125A(B), the control circuitry was designed in such a manner that,
once a containment spray actuation signal exists, the valves cannot be shut until
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the containment spray actuation signal clears; however, the circuitry could be
jumpered to allow closure of the valve in the malfunctioning containment system
train. This is significant since an alternate isolation valve cannot be closed until 6
hours after a LOCA because of high radiation levels in the minus t' foot valve
enclosure bay area of the reactor auxil!ary building.
b.2 CCW to Containment Fan Cooler Containment Isolation Valves
CCW to the containment fan cooler lines penetrate containment through
Penetrations 15 through 22. Technical Requirements Manual Table 3.6-2 lists the
CCW to containment fan cooler valves as containment isolation valves applicable to
Technical Specification 3.6.3 Further, UFSAR Table 6.2.32 listed Valves
CC-807A(B), -808,A(B), -822A(B), and -823A(B) as containment isolation valves.
The CCW air-operated, betterfly CCW to containment fan cooler isolation valves fail
open on loss of IA. Nonsafety-related IA is the normal air supply with backup air
being supplied by safety-related air accumulators.
The CCW to containment fan cooler lines form closed systems inside containment.
GDC 57 specifies that for closed systems that penetrate containment, the lines shall
have at least one containment isolation valve which is either automatic, or locked
closed, or capable of remote manual operation that is located outside containment.
The inspectors determined that the containment isolation provisions were satisfied
for the CCW to containment fan cooler penetration lines by having a closed CCW
system inside containment and remote manual valves located outside containment.
Once a safety injection actuation signal exists, the control circuitry for the
containment fan cooler isolation valves does not allow the CCW to containment fan
cooler isolation valves to be shut until the safety injection actuation signal clears; ;
however, the circuitry could be jumpered around to allow closure of the valve in the '
malfunctioning CCW system train.
b.3 Common Containment isolation Requirements
Regulatory Guide 1.141, " Containment isolation Provisions for Fluid Systems," April
1978, endorsed the use of ANSI N271-1976, with some exceptions not applicable
to the affected valves. ANSI N-271 approved containment configurations required
to meet GDC 56 and 57. Safety Evaluation Report, Section 6.2.4, " Containment
Isolation System," stated, in part, that the containment isolation provisions met the
requirements of GDC 54,55,56, and 57, and satisfied the guidance of Regulatory
Guide 1.141.
UFSAR Section 6.2.4.1.2, " Criteria for Isolation of Fluid Systems Penetrating the
Containment," required that each penetration line contain one isolation valve outside )
containment that shall be capable of either automatic or remote manual operation or J
locked closed. Further, Section 6.2.4.1.2 required that remote manual valves have '
the capability to be shut to isolate a faulted ESF system and that " Valves isolating
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penetrating lines serving engineered safety feature systems are not closed
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automatically by the CIAS [ containment isolation actuation signal], but have the '
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ability to be closed by remote manual operatior, f,om the main control room, thereby '
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isolating any engineered safety feature system which malfunctions." The inspectors
' determined that UFSAR Section 6.2.4.1.2 was consistent with regulatory
requirements.
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j b.4 Licensee Position for ESF System Containment isolation Valves '
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Throughout the inspection and during the exit meeting, licensee management
j maintained the following positions:
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Based on the original design and licensing of the plant, the subject
valves were considered containment isolation valves.
All regulatory requirements for containment isolation were satisfied.
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The subject valves did not have a closed safety function.
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' The NRC's preliminary position that the valves have a closed safety ;
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function is a backfit.
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No testing was required to demonstrate the ability of the
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accu-ulators to provide backup air to stroke the subject valves in the
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closed direction and to maintain the a closed since the valves did not
i have a closed safety function.
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The licensee maintained that Valves CS-125A(B) never had a closed safety function
} as discussed in various letters between the utility and the NRC. The licensee
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contended that Letter W3P84-0577, dated March 16,1984, informed the NRC that
a water barrier would be maintained in the containment spray system piping. ,
j Discussions with various licensing personnel indicated that, based upon this letter,
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the licensee determined that Valves CS-125A(B) did not have a closed safety
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function and that containment integrity would be maintained with the water barrier ,
" in the containment spray system because it formed a closed system outside '
containment.
1
{ The inspectors noted that Letter W3P84-0577 was used to justify relief from
performing Appendix J leak rate testing on various containment isolation valves, i
p including Valves CS-125A(B). Enclosure 1, of the letter, indicated that a water
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barrier could be maintained in the containment spray system piping for 30 days !
assuming Valves CS-125A(B) remained closed. However, the valves fail open on l
} loss of IA and cannot be closed without using some type of backup air.
.
From 1989 to 1994, internal licensee correspondence documented the safety
function (both open and closed) for valves CS-125A(B). In 1994, the licensee '
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concluded the valves had no closed safety function and discontinued accumulator
testing in August 1994 (last test completed March 8,1994 under Work
Authorization 01121332). This was documented in a 10 CFR 50.59 screening
titled " Revision 1 to STA-001-005, Leakage Testing of Air and Nitrogen
Accumulators Safety-Related Valve." The licensee justified not testing CS-125A(B)
because, " credit may be taken for containment spray train isolation using CS-
117A(B) [stop check valve located outside containment] and CS-118A(B) (normally
closed manual recirculation valve to tha RWSP]. The CS-125A(B) accumulator tests
are therefore not required."
The licensee also maintained that the CCW to containment fan cooler isolation
valves did not have a closed safety function. Various licensee documents justified
this position by stating that the CCW system is classified as a Seismic Category 1,
Safety Class 3, closed system whose failure does not have to be postulated during
a loss of coolant accident. Therefore, the containment isolation barrier would be
the CCW piping system inside containment.
During the inspection and at the exit, licensee management stated that they
believed the original design was consistent with regulatory requirements. Licensee
management contended that the NRC knew that the containment spray header and
CCW to containment fan cooler containment isolation valves could not be shut once
a containment . spray actuation signal or safety injection actuation signal existed and,
therefore, licensed the plant with an approved containment penetration design.
Further, management indicated that the requirement for these valves to have a
closed safety function was a change in previous NRC position, thereby constituting
.
a backfit.
b.5 Licensee and NRC Management Conference Call
On October 25,1996, Region IV and NRR personnel, including NRC management,
held a conference call with the licensee to understand the licensee's position.
During this call, NRC agreed to allow the licensee time to submit a letter detailing
the licensing basis for the subject containment isolation valves. In the interim, the
Vice President, Operations, committed to performing actions to ensure the isolation
capacity of the associated penetrations while NRC evaluated the licensee's position.
The commitment involved testing of each containment isolation valve accumulator
and establishing procedural guidance to enable closure of the valves from the
control room for a line or system fault during accident conditions.
The ten containment isolation valve accumulators and actuating systems were leak
tested satisfactorily by November 8,1996. Valves CS-125A(B) passed without any
rework. All of the CCW to containment fan cooler isolation valves required
extensive rework. Numerous leaks were repaired on fittings, solenoid valves, and
actuating mechanistas. The leakage would have prevented the ability to maintain
the valves closed, if containment isolation was required.
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Independent of the licensee submittal, Region IV submitted Task interface
Agreement 96TIA017, dated November 13,1996, requesting NRR to review the
regulatory requirements for isolation and closure capability for the containment
isolation valves. Pending NRR's review of Task Interface Agreement 96TIA017, the
operability requirements of the containment spray and CCW to containment fan
cooler isolation valves are identified as an unresolved item (382/9624-03).
c. Conclusions
From review of regulatory requirements and discussions with NRR Containment
System Branch personnel, it appeared that Valves CS-125A(B) and the CCW to
containment fan cooler containment isolation valves have a closed safety function.
Specifically, the valves are required to have the capability to close in case of a line ,
or system malfunction in order to maintain containment integrity under all I
conditions. However, because of the position expressed by the licensee, Region IV
has requested a formal review of the regulatory requirements from NRR.
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- ATTACHMENT 3
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April 22,1997
MEMORANDUM TO: Thomas P. Gwynn, Director ,
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Division of Reactor Projects, RIV i
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4 FROM: William D. Beckner, Director /S/ ORlG SIGNED BY: JHall for
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Project Directorate IV-1
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Division of Reactor Projects lil/IV 4
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TASK INTERFACE AGREEMENT (TIA)- WATERFORD 3 - REQUIREMENTS i
' FOR THE CAPABILITY OF CONTAINMENT ISOLATION VALVES TO CLOSE I
i TO MAINTAIN CONTAINMENT INTEGRITY (TAC NO. M97234)
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in a memorandum dated November 13,1996, from J. E. D ,.. to W. D. Beckner, Region IV
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requested the Office of Nuclear Reactor Regulation (NRR) to review the licensee's position
j on compliance with the general design criteria for dual function (i.e., open safety function
on a safety injection actuation signal and/or containment function to isolate the
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containment) air-operated containment penetration valves. On March 18,1997, the NRR
{ and Region IV staff met with the licensee to discuss containment isolation design and
- licensing basis for Waterford Steam Electric Station, Unit 3. While some more discussion
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with the licensee regarding the long term resolution of the detailed design issues is
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required, the NRR has determined that the staff position is clear as discussed below.
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Before addressing the specific designs, one needs to understand the roles of a system
} safety function and containment isolation function. In general, a system which penetrates
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containment has an important role to play in the overall operation of the plant. Some
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perform a safety function in a pre / post loss of coolant accident (LOCA) manner while
others are important to the overall operation of the plant. In either case, however, the
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requirement to perform a containment isolation function is the same. Containment
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isolation is always considered to be a safety function. The only remaining question is
{ when the isolation function needs to be performed.
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i Let us reverse the order and first discuss the role of the containment isolation valves for a i
nonsafety system. For this system class, it is normally assumed that the need for the l
system function ceases when the need for containment isolation is identified. Receipt of a )
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containment isolation signal will cause the containment isolation valves to automatically
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actuate. This satisfies (na containment function while at the same time ending the normal
j functioning of the system.
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The safety system containment isolation philosophy is quite similar. The difference relates !
to the priority of the function. Unlike for a nonsafety system, the safety system function
does not cease when the need for containment isolation is identified. The safety function l
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simply takes priority over containment isolation. As long as the system is able to provide
its safety function, containment isolation should not be implemented. However, if the
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system is not able to perform its safety function, then containment isolation becomes its I
- number one priority.
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By having the safety system function take first priority eliminates the need for automatic
containment isolation. Remote isolation is the accepted mode for this type of system.
With remote isolation capability, however, comes the need to know when isolation is
needed. This generally means leak detection and some means to determine system
operability.
Once it is determined that the safety function is not operable, containment isolation
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becomes the number one priority. The operators are trained to properly isolate the system i
which means closing both containment isolation valves. l
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Now, let us look at the requirements to isolate. The function must be fully safety grade. ]
This means that the instrumentation, motive power, actuator, and valve must be all safety I
grade, if the valve is motor operated, it should be Class ?E powered. For air power, the '
valve should either close upon loss of air supply or the supply should be considered l
essential which generally implies an adequately sized accumulator that will assure valve
closure for 30 days.
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Therefore, for systems with a dual requirement, the valves can and probably will have a ;
two position criteria. To satisfy the safety system function, the valve position should be
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open. However, to satisfy the containment isolation function, valve position should be
closed. To simply look at the safety system function to establish valve position meets only
half of the valve requirements. Additionally, to power the valve actuator with a nonsafety
air supply is unacceptable when the failure position is open since the containment isolation
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function cannot be satisfied.
With this brief background, one can now discuss the specific questions contained with the
TIA request. _Specifically, Region IV has identified the following questions:
QUESTION 1
Does the licensee comply with the requirements of Criterion 57 (i.e., do the
containment spray and component cooling water containment penetration valves
have a closed safety function?). In particular, are the air-operated valve
accumulators required to maintain the valves closed on a loss of nonsafety related
instrument air?
RESPONSE
The valves in question have dual requirements. For the system safety function, the
valves have an open function to assure the operability of the system when needed.
However, the valves also have a containment isolation function when called upon.
Under this sequence, the valves have a closed function. As discussed above, the
system safety function has first priority. Therefore, the fail open design is
appropriate. But, the containment isolation function is equally important when the
situation calls for isolation. This means that the air supply should be safety grade
to minimize the times when one loses the air supply to the valvs which also loses
the containment isolation function. The design needs safety accumulators to assure
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an air supply in the event of loss of nonsafety instrume it air. For this reason, it is
unacceptable to have nonsafety instrument air without s safety backup system.
Q UESTION 2
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Would similar valves for containment penetrations subjr et to the requirements of
Criteria 55 and 56 also have a closed safety function fc containment isolation, i
even if, the position of greater safety of the valve is to open?
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RESPONSE
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All containment isolation valves subject to the requirem nts of i
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Criteria 55 and 56 have a closed safety function. Howi ver, it is quite
misleading to state that the position of greater safety ol' the valve is to
open. These valves under discussion have a dual requii iment; performance of
the system safety function and the containment isolatic'i function. Each function is
a separate responsibility. Therefore, for the system safe ty function, the position of
greater safety is open. But for the containment isolation function, the position of
greater safety is closed. Since the system function has tPst priority, the valve
should f ail open upon loss of air. However, since the containment isolation position
of greater safety is closed, the air supply should be as reable as possible to
minimize the probability of the loss of air. This is translatul to mean safety grade.
QUESTION 3
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is the licensee required to have the capability of remote manual closure of the
containment penetration valves with a safety injection actustion signal and/or
containment spray actuation signal present?
RESPONSE
The simple response is yes. The licensee is required to be able to remotely close
the valve at any time during the transient. This is om'icularly irr,portant if the safety !
system has a burned in signal to stay open to mai.nai n the safety system function.
The solution is to design the logic such that a switch in the control room can be
actuated to override this open signal. An example of such a design can be found on
the containment isolation valves connected to an external recombiner. Normally the
valves are in a closed position. To allow the recombiner to become operational,
these valves must be opened even though there exists a containment isolation
signal. This override logic eliminates the need to jumper the connections within the
control cabinet which would be necessary without this control logic.
Equally important to the ability to change valve position is knowing when to initiate
containment isolation. Sufficient instrumentation should be available to the operator
for this purpose. This would include leak detection as well as sufficient
discrimination to determine which system is leaking.
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QUESTION 4
If the answer to Question 3 is yes, are manual actions an acceptable means of
meeting this requirement?
RESPONSE
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Manual action is an acceptable means for meeting this requirement. But, it should
be remote manual and normally from the control room.
With respect to the acceptability of the accumulators that exist at Waterford 3, we are
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planning to discuss this issue with the licensee. We willinclude Region IV staff in all of i
our future interactions with licensee on this issue.
cc: C. Hehl, Ri
J. Johnson, Ril
J. Caldwell, Rill
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