IR 05000382/1984005
Text
i
%
,t u,
k*
/d
.
MAR 011934
.
Docket No. 50-382 MEMORANDUM FOR:
George W. Knighton, Chief, Licensing Branch No. 3, NRR FROM:
Richard L. Bangart, Director, Division of Technical Programs, Region IV SUBJECT:
INSPECTION OF THE POSTACCIDENT SAMPLING SYSTEM FOR WATERFORD STEAM ELECTRIC STATION, UNIT 3 During a recent inspection (January 1984) by this office of the postaccident sampling system (PASS) at Waterford Unit No. 3 (WF-3), several concerns regarding the system design and operability were identified by the inspector.
These concerns were discussed with Mr. J. Wilson of your staff and Mr. F. Witt, CHEB/NRR, during telephone conversations with the inspector on January 30, 1984 This memorandum is being provided for your information on the concerns raised by the inspector.
Following is a discussion of those concerns preceded by a short description of the physical layout of the PASS.
WF-3 PASS Layout The system, as found, is described in Section 9.3 3.3 and Figure 9.3-11 of the FSAR (Ammendment No. 28). The following clarification of actual component location is provided:
Skid No. 2, " Sample Station," is actually a valving and depressurization
station located within a metal cabinet in a shielded cubicle. This is separated from the sample stations for undiluted reactor coolant, diluted reactor coolant, and reactor coolant gas samples which are located in a separate but adjacent shielded cubicle. The aforementioned components are located in a wing area of the reactor iuxiliary building (RAB) at elevation +21' 0" along with the PASS control panels (Skid No. 4) which are located adjacent to the two open top shielded cubicles.
Both the valving /depressurization and diluted reactor coolant sample
cabinets are equipped with liquid drains to the No. 4 sump of the RAB.
A ventilation manifold is located over the shielded cubicle housing the
sample panels, including the containment atmosphere grab sample panel, and provides exhaust ventilation to the valving /depressurization cabinet, h
FRPS TPB DT fl RPSB /
RPB1 FRPS DChar.ey BMurray RH 11 RB M
WCrossman EJohnson 02/M/84 02/g/84 02/ W 84 02/; /84 02/96/84 03/ t /84 85100103s4 eso227 h M -/V' M PDR FOIA bf BERNABE84-206 PDR
.
-
-
.
,i
!
Y George W. Knighton-2-
.
diluted reactor coolant sample cabinet, and the reactor coolant gas sample cabinet. This manifold is connected to ventilation ducting that is then tied into the RAB H&V system.
The containment atmosphere sampling system, which-is not discussed in the
FSAR, is tied into the plants hydrogen monitoring system (two redundant systems A&B). Hydrogen monitor B is the motive force for the reactor containment atmosphere sampling system and is located in the same wing area of the RAS at elevation -4' 0" as some of the PASS system components (Skids No. 1 & 3). Sample lines for containment atmosphere sampling are routed from the -4' -0" elevation to the same shielded cubicle housing the liquid and gas sample cabinets on the +21' -0" elevation.
Discussion of Concerns
,
1.
The liquid and gas sampling portion of PASS uses mechanical couplings (Swagelok) for component connections located on the -4' -0" and +21' -0" elevations of the RAB. Some of these connections are located outside of containments (cabinets), and resultant leakage would be vented directly to the adjacent area. This is a potential problem in regard to the wing area of the RAB at the +21' -0" elevation which must be accessible for postaccident samplings. The PASS was not discussed in the FSAR, Section 1.9.37, as requiring system integrity verification. Since this system will carry radioactivity with accident condition concentrations, there should be no leakage allowed, which is not probable with so many mechanical joints.
2.
The exhaust ventilation system provided for the PASS cabinets on the
+21' -0" elevation of the RAB is ducted to a common manifold located imediately above the cubicle containing the grab sample panels.
If a leak were to occur in the valving /depressurization cabinet, high level radioactivity would be drawn from the cabinet into the ventilation system.
There could not be found any evaluation as to the effect this would have on accessibility of the area and the PASS control panel (Skid No. 4) which is located adjacent to the exhaust ventilation duct outside of the shielded cubicle. This matter was not addressed in the shielding review conducted by the licensee to satisfy NUREG 0737, Item II.B.2.
3.
The sample valving /depressurization and the diluted reactor coolant cabinets both are provided with a drain system for system leakage that utilizes
"S" type traps and check valves near the bottom of the cabinets.
The traps and check valves have socket welded couplings, 90' elbows, and valves.
Since the traps are located near.the cabinets, and in the case of the diluted reactor sample cabinet at waist height, there is concern
,
that unnecessary radiation exposur!. will be received by personnel both during routine maintenance / testing and actual accident operation. Also, there is the possibility of a significant radiation hot spot being created in the traps due to the build up of radioactivity that will resist removal
.
,
-
- - -
,-
,~,
YI George W. Knighton-3-by flushing due to the system design. This is basically a poor design practice and does not reflect proper ALARA considerations.
,
4.
The containment atmosphere sampling system does not satisfy the recommendations of ANSI N13.1-1969 for an air sampling system.
It is possible that the system will not provide accurate samples of iodines or particles during use. The licensee has also questioned the design con-cerning the ability of the system to draw representative samples (see WF-3 construction CIWA 83E507, dated December 21,1983). The design contractor had submitted a theoretical study / evaluation of sampling line losses during system operation. The contractor used the guidelines provided in ANSI N13.1-1969, Appendix B and a TMI source term to arrive at sample line losses. The study used a simplified sampling line geometry that included vertical and horizontal sample line runs and 22, 90* bends. A walk down of the one sampling line (one of eight available and considered the worst case) revealed that the study greatly underestimated the number of restrictions in the system. The following restrictions were noted:
,
approximately 30, 90* bends
approximately 12, socket welded "T" joints
approximately 10, socket welded valves
approximately 5, socket welded couplings
The licensee also had not developed a proper preoperational testing program to verify that representative samples can be obtained. There also exists the possibility that due to the numerous restrictions in the system, that representative sampling may be impossible. This aspect of the containment atmosphere sample system may be a generic concern throughout the nuclear industry.
5.
The containment atmosphere grab sample panel on the +21' -0" elevation of the RAB (same location as the liquid anc gas sample panels) had not been
!
evaluated per Item II.B.2. of NUREG 0737 based on drawing undiluted containment atmosphere samples and the resultant source term created in the sampling cubicle due to filter and cartridge radioactivity loading.
..
--
'
/
-4 George W. Knighton
,
The above noted concerns are addressed as o;:en items in NRC Inspection Report 50-382/84-05. Since most of the initial evaluation of the PASS has been between NRR and the licensee, we request that you review our concerns and suggest possible resolutions of these problem areas.
Original Signed By
, R. L. Bangart, D.irector Division of Technical Programs
.
cc:
J. Collins R. Denise E. Johnson W. Crossman B. Murray T. Martin, RI R. Stohr, RII J. Hind, RIII R. Scarano, RV J. Wilson, LB3 F. Witt, CHEB 5. Block, RAB R. DeYoung, IE bec:
D. Chaney TPB RIV Files L. Constable
.
n